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![Al Viro](/assets/img/avatar_default.png)
All other callers already hold either ->mmap_sem (exclusive) or ->page_table_lock. And we need it because some page table flushing instanced do work explicitly with ge tables. See e.g. arch/powerpc/mm/tlb_hash32.c, flush_tlb_range() and flush_range() in there. The same goes for uml, with a lot more extensive playing with page tables. Almost all callers are actually fine - flush_tlb_range() may have no need to bother playing with page tables, but it can do so safely; again, this caller is the sole exception - everything else either has exclusive ->mmap_sem on the mm in question, or mm->page_table_lock is held. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2983 lines
77 KiB
C
2983 lines
77 KiB
C
/*
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* Generic hugetlb support.
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* (C) William Irwin, April 2004
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*/
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#include <linux/list.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/seq_file.h>
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#include <linux/sysctl.h>
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#include <linux/highmem.h>
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#include <linux/mmu_notifier.h>
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#include <linux/nodemask.h>
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#include <linux/pagemap.h>
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#include <linux/mempolicy.h>
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#include <linux/cpuset.h>
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#include <linux/mutex.h>
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#include <linux/bootmem.h>
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#include <linux/sysfs.h>
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#include <linux/slab.h>
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#include <linux/rmap.h>
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#include <linux/swap.h>
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#include <linux/swapops.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <linux/io.h>
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#include <linux/hugetlb.h>
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#include <linux/node.h>
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#include "internal.h"
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const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL;
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static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
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unsigned long hugepages_treat_as_movable;
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static int max_hstate;
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unsigned int default_hstate_idx;
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struct hstate hstates[HUGE_MAX_HSTATE];
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__initdata LIST_HEAD(huge_boot_pages);
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/* for command line parsing */
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static struct hstate * __initdata parsed_hstate;
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static unsigned long __initdata default_hstate_max_huge_pages;
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static unsigned long __initdata default_hstate_size;
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#define for_each_hstate(h) \
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for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++)
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/*
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* Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
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*/
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static DEFINE_SPINLOCK(hugetlb_lock);
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/*
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* Region tracking -- allows tracking of reservations and instantiated pages
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* across the pages in a mapping.
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*
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* The region data structures are protected by a combination of the mmap_sem
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* and the hugetlb_instantion_mutex. To access or modify a region the caller
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* must either hold the mmap_sem for write, or the mmap_sem for read and
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* the hugetlb_instantiation mutex:
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*
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* down_write(&mm->mmap_sem);
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* or
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* down_read(&mm->mmap_sem);
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* mutex_lock(&hugetlb_instantiation_mutex);
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*/
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struct file_region {
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struct list_head link;
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long from;
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long to;
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};
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static long region_add(struct list_head *head, long f, long t)
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{
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struct file_region *rg, *nrg, *trg;
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/* Locate the region we are either in or before. */
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list_for_each_entry(rg, head, link)
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if (f <= rg->to)
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break;
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/* Round our left edge to the current segment if it encloses us. */
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if (f > rg->from)
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f = rg->from;
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/* Check for and consume any regions we now overlap with. */
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nrg = rg;
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list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
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if (&rg->link == head)
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break;
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if (rg->from > t)
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break;
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/* If this area reaches higher then extend our area to
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* include it completely. If this is not the first area
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* which we intend to reuse, free it. */
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if (rg->to > t)
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t = rg->to;
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if (rg != nrg) {
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list_del(&rg->link);
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kfree(rg);
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}
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}
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nrg->from = f;
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nrg->to = t;
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return 0;
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}
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static long region_chg(struct list_head *head, long f, long t)
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{
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struct file_region *rg, *nrg;
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long chg = 0;
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/* Locate the region we are before or in. */
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list_for_each_entry(rg, head, link)
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if (f <= rg->to)
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break;
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/* If we are below the current region then a new region is required.
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* Subtle, allocate a new region at the position but make it zero
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* size such that we can guarantee to record the reservation. */
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if (&rg->link == head || t < rg->from) {
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nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
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if (!nrg)
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return -ENOMEM;
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nrg->from = f;
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nrg->to = f;
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INIT_LIST_HEAD(&nrg->link);
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list_add(&nrg->link, rg->link.prev);
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return t - f;
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}
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/* Round our left edge to the current segment if it encloses us. */
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if (f > rg->from)
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f = rg->from;
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chg = t - f;
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/* Check for and consume any regions we now overlap with. */
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list_for_each_entry(rg, rg->link.prev, link) {
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if (&rg->link == head)
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break;
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if (rg->from > t)
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return chg;
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/* We overlap with this area, if it extends further than
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* us then we must extend ourselves. Account for its
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* existing reservation. */
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if (rg->to > t) {
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chg += rg->to - t;
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t = rg->to;
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}
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chg -= rg->to - rg->from;
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}
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return chg;
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}
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static long region_truncate(struct list_head *head, long end)
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{
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struct file_region *rg, *trg;
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long chg = 0;
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/* Locate the region we are either in or before. */
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list_for_each_entry(rg, head, link)
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if (end <= rg->to)
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break;
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if (&rg->link == head)
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return 0;
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/* If we are in the middle of a region then adjust it. */
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if (end > rg->from) {
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chg = rg->to - end;
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rg->to = end;
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rg = list_entry(rg->link.next, typeof(*rg), link);
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}
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/* Drop any remaining regions. */
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list_for_each_entry_safe(rg, trg, rg->link.prev, link) {
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if (&rg->link == head)
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break;
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chg += rg->to - rg->from;
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list_del(&rg->link);
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kfree(rg);
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}
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return chg;
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}
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static long region_count(struct list_head *head, long f, long t)
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{
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struct file_region *rg;
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long chg = 0;
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/* Locate each segment we overlap with, and count that overlap. */
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list_for_each_entry(rg, head, link) {
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int seg_from;
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int seg_to;
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if (rg->to <= f)
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continue;
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if (rg->from >= t)
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break;
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seg_from = max(rg->from, f);
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seg_to = min(rg->to, t);
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chg += seg_to - seg_from;
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}
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return chg;
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}
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/*
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* Convert the address within this vma to the page offset within
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* the mapping, in pagecache page units; huge pages here.
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*/
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static pgoff_t vma_hugecache_offset(struct hstate *h,
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struct vm_area_struct *vma, unsigned long address)
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{
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return ((address - vma->vm_start) >> huge_page_shift(h)) +
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(vma->vm_pgoff >> huge_page_order(h));
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}
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pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
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unsigned long address)
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{
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return vma_hugecache_offset(hstate_vma(vma), vma, address);
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}
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/*
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* Return the size of the pages allocated when backing a VMA. In the majority
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* cases this will be same size as used by the page table entries.
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*/
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unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
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{
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struct hstate *hstate;
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if (!is_vm_hugetlb_page(vma))
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return PAGE_SIZE;
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hstate = hstate_vma(vma);
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return 1UL << (hstate->order + PAGE_SHIFT);
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}
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EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
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/*
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* Return the page size being used by the MMU to back a VMA. In the majority
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* of cases, the page size used by the kernel matches the MMU size. On
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* architectures where it differs, an architecture-specific version of this
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* function is required.
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*/
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#ifndef vma_mmu_pagesize
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unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
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{
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return vma_kernel_pagesize(vma);
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}
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#endif
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/*
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* Flags for MAP_PRIVATE reservations. These are stored in the bottom
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* bits of the reservation map pointer, which are always clear due to
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* alignment.
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*/
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#define HPAGE_RESV_OWNER (1UL << 0)
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#define HPAGE_RESV_UNMAPPED (1UL << 1)
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#define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
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/*
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* These helpers are used to track how many pages are reserved for
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* faults in a MAP_PRIVATE mapping. Only the process that called mmap()
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* is guaranteed to have their future faults succeed.
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*
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* With the exception of reset_vma_resv_huge_pages() which is called at fork(),
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* the reserve counters are updated with the hugetlb_lock held. It is safe
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* to reset the VMA at fork() time as it is not in use yet and there is no
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* chance of the global counters getting corrupted as a result of the values.
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*
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* The private mapping reservation is represented in a subtly different
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* manner to a shared mapping. A shared mapping has a region map associated
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* with the underlying file, this region map represents the backing file
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* pages which have ever had a reservation assigned which this persists even
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* after the page is instantiated. A private mapping has a region map
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* associated with the original mmap which is attached to all VMAs which
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* reference it, this region map represents those offsets which have consumed
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* reservation ie. where pages have been instantiated.
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*/
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static unsigned long get_vma_private_data(struct vm_area_struct *vma)
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{
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return (unsigned long)vma->vm_private_data;
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}
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static void set_vma_private_data(struct vm_area_struct *vma,
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unsigned long value)
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{
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vma->vm_private_data = (void *)value;
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}
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struct resv_map {
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struct kref refs;
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struct list_head regions;
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};
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static struct resv_map *resv_map_alloc(void)
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{
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struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
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if (!resv_map)
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return NULL;
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kref_init(&resv_map->refs);
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INIT_LIST_HEAD(&resv_map->regions);
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return resv_map;
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}
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static void resv_map_release(struct kref *ref)
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{
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struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
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/* Clear out any active regions before we release the map. */
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region_truncate(&resv_map->regions, 0);
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kfree(resv_map);
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}
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static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
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{
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VM_BUG_ON(!is_vm_hugetlb_page(vma));
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if (!(vma->vm_flags & VM_MAYSHARE))
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return (struct resv_map *)(get_vma_private_data(vma) &
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~HPAGE_RESV_MASK);
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return NULL;
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}
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static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
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{
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VM_BUG_ON(!is_vm_hugetlb_page(vma));
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VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
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set_vma_private_data(vma, (get_vma_private_data(vma) &
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HPAGE_RESV_MASK) | (unsigned long)map);
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}
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static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
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{
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VM_BUG_ON(!is_vm_hugetlb_page(vma));
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VM_BUG_ON(vma->vm_flags & VM_MAYSHARE);
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set_vma_private_data(vma, get_vma_private_data(vma) | flags);
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}
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static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
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{
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VM_BUG_ON(!is_vm_hugetlb_page(vma));
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return (get_vma_private_data(vma) & flag) != 0;
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}
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/* Decrement the reserved pages in the hugepage pool by one */
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static void decrement_hugepage_resv_vma(struct hstate *h,
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struct vm_area_struct *vma)
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{
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if (vma->vm_flags & VM_NORESERVE)
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return;
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if (vma->vm_flags & VM_MAYSHARE) {
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/* Shared mappings always use reserves */
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h->resv_huge_pages--;
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} else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
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/*
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* Only the process that called mmap() has reserves for
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* private mappings.
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*/
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h->resv_huge_pages--;
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}
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}
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/* Reset counters to 0 and clear all HPAGE_RESV_* flags */
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void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
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{
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VM_BUG_ON(!is_vm_hugetlb_page(vma));
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if (!(vma->vm_flags & VM_MAYSHARE))
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vma->vm_private_data = (void *)0;
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}
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/* Returns true if the VMA has associated reserve pages */
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static int vma_has_reserves(struct vm_area_struct *vma)
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{
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if (vma->vm_flags & VM_MAYSHARE)
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return 1;
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if (is_vma_resv_set(vma, HPAGE_RESV_OWNER))
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return 1;
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return 0;
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}
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static void copy_gigantic_page(struct page *dst, struct page *src)
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{
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int i;
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struct hstate *h = page_hstate(src);
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struct page *dst_base = dst;
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struct page *src_base = src;
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for (i = 0; i < pages_per_huge_page(h); ) {
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cond_resched();
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copy_highpage(dst, src);
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i++;
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dst = mem_map_next(dst, dst_base, i);
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src = mem_map_next(src, src_base, i);
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}
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}
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void copy_huge_page(struct page *dst, struct page *src)
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{
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int i;
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struct hstate *h = page_hstate(src);
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if (unlikely(pages_per_huge_page(h) > MAX_ORDER_NR_PAGES)) {
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copy_gigantic_page(dst, src);
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return;
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}
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might_sleep();
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for (i = 0; i < pages_per_huge_page(h); i++) {
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cond_resched();
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copy_highpage(dst + i, src + i);
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}
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}
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static void enqueue_huge_page(struct hstate *h, struct page *page)
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{
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int nid = page_to_nid(page);
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list_add(&page->lru, &h->hugepage_freelists[nid]);
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h->free_huge_pages++;
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h->free_huge_pages_node[nid]++;
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}
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static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
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{
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struct page *page;
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if (list_empty(&h->hugepage_freelists[nid]))
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return NULL;
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page = list_entry(h->hugepage_freelists[nid].next, struct page, lru);
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list_del(&page->lru);
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set_page_refcounted(page);
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h->free_huge_pages--;
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h->free_huge_pages_node[nid]--;
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return page;
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}
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|
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static struct page *dequeue_huge_page_vma(struct hstate *h,
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struct vm_area_struct *vma,
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unsigned long address, int avoid_reserve)
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{
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struct page *page = NULL;
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struct mempolicy *mpol;
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nodemask_t *nodemask;
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struct zonelist *zonelist;
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struct zone *zone;
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struct zoneref *z;
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get_mems_allowed();
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zonelist = huge_zonelist(vma, address,
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htlb_alloc_mask, &mpol, &nodemask);
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/*
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* A child process with MAP_PRIVATE mappings created by their parent
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* have no page reserves. This check ensures that reservations are
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* not "stolen". The child may still get SIGKILLed
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*/
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if (!vma_has_reserves(vma) &&
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h->free_huge_pages - h->resv_huge_pages == 0)
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goto err;
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/* If reserves cannot be used, ensure enough pages are in the pool */
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if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
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goto err;
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|
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for_each_zone_zonelist_nodemask(zone, z, zonelist,
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MAX_NR_ZONES - 1, nodemask) {
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if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) {
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page = dequeue_huge_page_node(h, zone_to_nid(zone));
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if (page) {
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if (!avoid_reserve)
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decrement_hugepage_resv_vma(h, vma);
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break;
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}
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}
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}
|
|
err:
|
|
mpol_cond_put(mpol);
|
|
put_mems_allowed();
|
|
return page;
|
|
}
|
|
|
|
static void update_and_free_page(struct hstate *h, struct page *page)
|
|
{
|
|
int i;
|
|
|
|
VM_BUG_ON(h->order >= MAX_ORDER);
|
|
|
|
h->nr_huge_pages--;
|
|
h->nr_huge_pages_node[page_to_nid(page)]--;
|
|
for (i = 0; i < pages_per_huge_page(h); i++) {
|
|
page[i].flags &= ~(1 << PG_locked | 1 << PG_error |
|
|
1 << PG_referenced | 1 << PG_dirty |
|
|
1 << PG_active | 1 << PG_reserved |
|
|
1 << PG_private | 1 << PG_writeback);
|
|
}
|
|
set_compound_page_dtor(page, NULL);
|
|
set_page_refcounted(page);
|
|
arch_release_hugepage(page);
|
|
__free_pages(page, huge_page_order(h));
|
|
}
|
|
|
|
struct hstate *size_to_hstate(unsigned long size)
|
|
{
|
|
struct hstate *h;
|
|
|
|
for_each_hstate(h) {
|
|
if (huge_page_size(h) == size)
|
|
return h;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static void free_huge_page(struct page *page)
|
|
{
|
|
/*
|
|
* Can't pass hstate in here because it is called from the
|
|
* compound page destructor.
|
|
*/
|
|
struct hstate *h = page_hstate(page);
|
|
int nid = page_to_nid(page);
|
|
struct address_space *mapping;
|
|
|
|
mapping = (struct address_space *) page_private(page);
|
|
set_page_private(page, 0);
|
|
page->mapping = NULL;
|
|
BUG_ON(page_count(page));
|
|
BUG_ON(page_mapcount(page));
|
|
INIT_LIST_HEAD(&page->lru);
|
|
|
|
spin_lock(&hugetlb_lock);
|
|
if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
|
|
update_and_free_page(h, page);
|
|
h->surplus_huge_pages--;
|
|
h->surplus_huge_pages_node[nid]--;
|
|
} else {
|
|
enqueue_huge_page(h, page);
|
|
}
|
|
spin_unlock(&hugetlb_lock);
|
|
if (mapping)
|
|
hugetlb_put_quota(mapping, 1);
|
|
}
|
|
|
|
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
|
|
{
|
|
set_compound_page_dtor(page, free_huge_page);
|
|
spin_lock(&hugetlb_lock);
|
|
h->nr_huge_pages++;
|
|
h->nr_huge_pages_node[nid]++;
|
|
spin_unlock(&hugetlb_lock);
|
|
put_page(page); /* free it into the hugepage allocator */
|
|
}
|
|
|
|
static void prep_compound_gigantic_page(struct page *page, unsigned long order)
|
|
{
|
|
int i;
|
|
int nr_pages = 1 << order;
|
|
struct page *p = page + 1;
|
|
|
|
/* we rely on prep_new_huge_page to set the destructor */
|
|
set_compound_order(page, order);
|
|
__SetPageHead(page);
|
|
for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
|
|
__SetPageTail(p);
|
|
set_page_count(p, 0);
|
|
p->first_page = page;
|
|
}
|
|
}
|
|
|
|
int PageHuge(struct page *page)
|
|
{
|
|
compound_page_dtor *dtor;
|
|
|
|
if (!PageCompound(page))
|
|
return 0;
|
|
|
|
page = compound_head(page);
|
|
dtor = get_compound_page_dtor(page);
|
|
|
|
return dtor == free_huge_page;
|
|
}
|
|
EXPORT_SYMBOL_GPL(PageHuge);
|
|
|
|
static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
|
|
{
|
|
struct page *page;
|
|
|
|
if (h->order >= MAX_ORDER)
|
|
return NULL;
|
|
|
|
page = alloc_pages_exact_node(nid,
|
|
htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
|
|
__GFP_REPEAT|__GFP_NOWARN,
|
|
huge_page_order(h));
|
|
if (page) {
|
|
if (arch_prepare_hugepage(page)) {
|
|
__free_pages(page, huge_page_order(h));
|
|
return NULL;
|
|
}
|
|
prep_new_huge_page(h, page, nid);
|
|
}
|
|
|
|
return page;
|
|
}
|
|
|
|
/*
|
|
* common helper functions for hstate_next_node_to_{alloc|free}.
|
|
* We may have allocated or freed a huge page based on a different
|
|
* nodes_allowed previously, so h->next_node_to_{alloc|free} might
|
|
* be outside of *nodes_allowed. Ensure that we use an allowed
|
|
* node for alloc or free.
|
|
*/
|
|
static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
|
|
{
|
|
nid = next_node(nid, *nodes_allowed);
|
|
if (nid == MAX_NUMNODES)
|
|
nid = first_node(*nodes_allowed);
|
|
VM_BUG_ON(nid >= MAX_NUMNODES);
|
|
|
|
return nid;
|
|
}
|
|
|
|
static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
|
|
{
|
|
if (!node_isset(nid, *nodes_allowed))
|
|
nid = next_node_allowed(nid, nodes_allowed);
|
|
return nid;
|
|
}
|
|
|
|
/*
|
|
* returns the previously saved node ["this node"] from which to
|
|
* allocate a persistent huge page for the pool and advance the
|
|
* next node from which to allocate, handling wrap at end of node
|
|
* mask.
|
|
*/
|
|
static int hstate_next_node_to_alloc(struct hstate *h,
|
|
nodemask_t *nodes_allowed)
|
|
{
|
|
int nid;
|
|
|
|
VM_BUG_ON(!nodes_allowed);
|
|
|
|
nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
|
|
h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
|
|
|
|
return nid;
|
|
}
|
|
|
|
static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed)
|
|
{
|
|
struct page *page;
|
|
int start_nid;
|
|
int next_nid;
|
|
int ret = 0;
|
|
|
|
start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
|
|
next_nid = start_nid;
|
|
|
|
do {
|
|
page = alloc_fresh_huge_page_node(h, next_nid);
|
|
if (page) {
|
|
ret = 1;
|
|
break;
|
|
}
|
|
next_nid = hstate_next_node_to_alloc(h, nodes_allowed);
|
|
} while (next_nid != start_nid);
|
|
|
|
if (ret)
|
|
count_vm_event(HTLB_BUDDY_PGALLOC);
|
|
else
|
|
count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* helper for free_pool_huge_page() - return the previously saved
|
|
* node ["this node"] from which to free a huge page. Advance the
|
|
* next node id whether or not we find a free huge page to free so
|
|
* that the next attempt to free addresses the next node.
|
|
*/
|
|
static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
|
|
{
|
|
int nid;
|
|
|
|
VM_BUG_ON(!nodes_allowed);
|
|
|
|
nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
|
|
h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
|
|
|
|
return nid;
|
|
}
|
|
|
|
/*
|
|
* Free huge page from pool from next node to free.
|
|
* Attempt to keep persistent huge pages more or less
|
|
* balanced over allowed nodes.
|
|
* Called with hugetlb_lock locked.
|
|
*/
|
|
static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
|
|
bool acct_surplus)
|
|
{
|
|
int start_nid;
|
|
int next_nid;
|
|
int ret = 0;
|
|
|
|
start_nid = hstate_next_node_to_free(h, nodes_allowed);
|
|
next_nid = start_nid;
|
|
|
|
do {
|
|
/*
|
|
* If we're returning unused surplus pages, only examine
|
|
* nodes with surplus pages.
|
|
*/
|
|
if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) &&
|
|
!list_empty(&h->hugepage_freelists[next_nid])) {
|
|
struct page *page =
|
|
list_entry(h->hugepage_freelists[next_nid].next,
|
|
struct page, lru);
|
|
list_del(&page->lru);
|
|
h->free_huge_pages--;
|
|
h->free_huge_pages_node[next_nid]--;
|
|
if (acct_surplus) {
|
|
h->surplus_huge_pages--;
|
|
h->surplus_huge_pages_node[next_nid]--;
|
|
}
|
|
update_and_free_page(h, page);
|
|
ret = 1;
|
|
break;
|
|
}
|
|
next_nid = hstate_next_node_to_free(h, nodes_allowed);
|
|
} while (next_nid != start_nid);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
|
|
{
|
|
struct page *page;
|
|
unsigned int r_nid;
|
|
|
|
if (h->order >= MAX_ORDER)
|
|
return NULL;
|
|
|
|
/*
|
|
* Assume we will successfully allocate the surplus page to
|
|
* prevent racing processes from causing the surplus to exceed
|
|
* overcommit
|
|
*
|
|
* This however introduces a different race, where a process B
|
|
* tries to grow the static hugepage pool while alloc_pages() is
|
|
* called by process A. B will only examine the per-node
|
|
* counters in determining if surplus huge pages can be
|
|
* converted to normal huge pages in adjust_pool_surplus(). A
|
|
* won't be able to increment the per-node counter, until the
|
|
* lock is dropped by B, but B doesn't drop hugetlb_lock until
|
|
* no more huge pages can be converted from surplus to normal
|
|
* state (and doesn't try to convert again). Thus, we have a
|
|
* case where a surplus huge page exists, the pool is grown, and
|
|
* the surplus huge page still exists after, even though it
|
|
* should just have been converted to a normal huge page. This
|
|
* does not leak memory, though, as the hugepage will be freed
|
|
* once it is out of use. It also does not allow the counters to
|
|
* go out of whack in adjust_pool_surplus() as we don't modify
|
|
* the node values until we've gotten the hugepage and only the
|
|
* per-node value is checked there.
|
|
*/
|
|
spin_lock(&hugetlb_lock);
|
|
if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
|
|
spin_unlock(&hugetlb_lock);
|
|
return NULL;
|
|
} else {
|
|
h->nr_huge_pages++;
|
|
h->surplus_huge_pages++;
|
|
}
|
|
spin_unlock(&hugetlb_lock);
|
|
|
|
if (nid == NUMA_NO_NODE)
|
|
page = alloc_pages(htlb_alloc_mask|__GFP_COMP|
|
|
__GFP_REPEAT|__GFP_NOWARN,
|
|
huge_page_order(h));
|
|
else
|
|
page = alloc_pages_exact_node(nid,
|
|
htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE|
|
|
__GFP_REPEAT|__GFP_NOWARN, huge_page_order(h));
|
|
|
|
if (page && arch_prepare_hugepage(page)) {
|
|
__free_pages(page, huge_page_order(h));
|
|
page = NULL;
|
|
}
|
|
|
|
spin_lock(&hugetlb_lock);
|
|
if (page) {
|
|
r_nid = page_to_nid(page);
|
|
set_compound_page_dtor(page, free_huge_page);
|
|
/*
|
|
* We incremented the global counters already
|
|
*/
|
|
h->nr_huge_pages_node[r_nid]++;
|
|
h->surplus_huge_pages_node[r_nid]++;
|
|
__count_vm_event(HTLB_BUDDY_PGALLOC);
|
|
} else {
|
|
h->nr_huge_pages--;
|
|
h->surplus_huge_pages--;
|
|
__count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
|
|
}
|
|
spin_unlock(&hugetlb_lock);
|
|
|
|
return page;
|
|
}
|
|
|
|
/*
|
|
* This allocation function is useful in the context where vma is irrelevant.
|
|
* E.g. soft-offlining uses this function because it only cares physical
|
|
* address of error page.
|
|
*/
|
|
struct page *alloc_huge_page_node(struct hstate *h, int nid)
|
|
{
|
|
struct page *page;
|
|
|
|
spin_lock(&hugetlb_lock);
|
|
page = dequeue_huge_page_node(h, nid);
|
|
spin_unlock(&hugetlb_lock);
|
|
|
|
if (!page)
|
|
page = alloc_buddy_huge_page(h, nid);
|
|
|
|
return page;
|
|
}
|
|
|
|
/*
|
|
* Increase the hugetlb pool such that it can accommodate a reservation
|
|
* of size 'delta'.
|
|
*/
|
|
static int gather_surplus_pages(struct hstate *h, int delta)
|
|
{
|
|
struct list_head surplus_list;
|
|
struct page *page, *tmp;
|
|
int ret, i;
|
|
int needed, allocated;
|
|
|
|
needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
|
|
if (needed <= 0) {
|
|
h->resv_huge_pages += delta;
|
|
return 0;
|
|
}
|
|
|
|
allocated = 0;
|
|
INIT_LIST_HEAD(&surplus_list);
|
|
|
|
ret = -ENOMEM;
|
|
retry:
|
|
spin_unlock(&hugetlb_lock);
|
|
for (i = 0; i < needed; i++) {
|
|
page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
|
|
if (!page)
|
|
/*
|
|
* We were not able to allocate enough pages to
|
|
* satisfy the entire reservation so we free what
|
|
* we've allocated so far.
|
|
*/
|
|
goto free;
|
|
|
|
list_add(&page->lru, &surplus_list);
|
|
}
|
|
allocated += needed;
|
|
|
|
/*
|
|
* After retaking hugetlb_lock, we need to recalculate 'needed'
|
|
* because either resv_huge_pages or free_huge_pages may have changed.
|
|
*/
|
|
spin_lock(&hugetlb_lock);
|
|
needed = (h->resv_huge_pages + delta) -
|
|
(h->free_huge_pages + allocated);
|
|
if (needed > 0)
|
|
goto retry;
|
|
|
|
/*
|
|
* The surplus_list now contains _at_least_ the number of extra pages
|
|
* needed to accommodate the reservation. Add the appropriate number
|
|
* of pages to the hugetlb pool and free the extras back to the buddy
|
|
* allocator. Commit the entire reservation here to prevent another
|
|
* process from stealing the pages as they are added to the pool but
|
|
* before they are reserved.
|
|
*/
|
|
needed += allocated;
|
|
h->resv_huge_pages += delta;
|
|
ret = 0;
|
|
|
|
/* Free the needed pages to the hugetlb pool */
|
|
list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
|
|
if ((--needed) < 0)
|
|
break;
|
|
list_del(&page->lru);
|
|
/*
|
|
* This page is now managed by the hugetlb allocator and has
|
|
* no users -- drop the buddy allocator's reference.
|
|
*/
|
|
put_page_testzero(page);
|
|
VM_BUG_ON(page_count(page));
|
|
enqueue_huge_page(h, page);
|
|
}
|
|
spin_unlock(&hugetlb_lock);
|
|
|
|
/* Free unnecessary surplus pages to the buddy allocator */
|
|
free:
|
|
if (!list_empty(&surplus_list)) {
|
|
list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
|
|
list_del(&page->lru);
|
|
put_page(page);
|
|
}
|
|
}
|
|
spin_lock(&hugetlb_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* When releasing a hugetlb pool reservation, any surplus pages that were
|
|
* allocated to satisfy the reservation must be explicitly freed if they were
|
|
* never used.
|
|
* Called with hugetlb_lock held.
|
|
*/
|
|
static void return_unused_surplus_pages(struct hstate *h,
|
|
unsigned long unused_resv_pages)
|
|
{
|
|
unsigned long nr_pages;
|
|
|
|
/* Uncommit the reservation */
|
|
h->resv_huge_pages -= unused_resv_pages;
|
|
|
|
/* Cannot return gigantic pages currently */
|
|
if (h->order >= MAX_ORDER)
|
|
return;
|
|
|
|
nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
|
|
|
|
/*
|
|
* We want to release as many surplus pages as possible, spread
|
|
* evenly across all nodes with memory. Iterate across these nodes
|
|
* until we can no longer free unreserved surplus pages. This occurs
|
|
* when the nodes with surplus pages have no free pages.
|
|
* free_pool_huge_page() will balance the the freed pages across the
|
|
* on-line nodes with memory and will handle the hstate accounting.
|
|
*/
|
|
while (nr_pages--) {
|
|
if (!free_pool_huge_page(h, &node_states[N_HIGH_MEMORY], 1))
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Determine if the huge page at addr within the vma has an associated
|
|
* reservation. Where it does not we will need to logically increase
|
|
* reservation and actually increase quota before an allocation can occur.
|
|
* Where any new reservation would be required the reservation change is
|
|
* prepared, but not committed. Once the page has been quota'd allocated
|
|
* an instantiated the change should be committed via vma_commit_reservation.
|
|
* No action is required on failure.
|
|
*/
|
|
static long vma_needs_reservation(struct hstate *h,
|
|
struct vm_area_struct *vma, unsigned long addr)
|
|
{
|
|
struct address_space *mapping = vma->vm_file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
|
|
if (vma->vm_flags & VM_MAYSHARE) {
|
|
pgoff_t idx = vma_hugecache_offset(h, vma, addr);
|
|
return region_chg(&inode->i_mapping->private_list,
|
|
idx, idx + 1);
|
|
|
|
} else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
|
|
return 1;
|
|
|
|
} else {
|
|
long err;
|
|
pgoff_t idx = vma_hugecache_offset(h, vma, addr);
|
|
struct resv_map *reservations = vma_resv_map(vma);
|
|
|
|
err = region_chg(&reservations->regions, idx, idx + 1);
|
|
if (err < 0)
|
|
return err;
|
|
return 0;
|
|
}
|
|
}
|
|
static void vma_commit_reservation(struct hstate *h,
|
|
struct vm_area_struct *vma, unsigned long addr)
|
|
{
|
|
struct address_space *mapping = vma->vm_file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
|
|
if (vma->vm_flags & VM_MAYSHARE) {
|
|
pgoff_t idx = vma_hugecache_offset(h, vma, addr);
|
|
region_add(&inode->i_mapping->private_list, idx, idx + 1);
|
|
|
|
} else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
|
|
pgoff_t idx = vma_hugecache_offset(h, vma, addr);
|
|
struct resv_map *reservations = vma_resv_map(vma);
|
|
|
|
/* Mark this page used in the map. */
|
|
region_add(&reservations->regions, idx, idx + 1);
|
|
}
|
|
}
|
|
|
|
static struct page *alloc_huge_page(struct vm_area_struct *vma,
|
|
unsigned long addr, int avoid_reserve)
|
|
{
|
|
struct hstate *h = hstate_vma(vma);
|
|
struct page *page;
|
|
struct address_space *mapping = vma->vm_file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
long chg;
|
|
|
|
/*
|
|
* Processes that did not create the mapping will have no reserves and
|
|
* will not have accounted against quota. Check that the quota can be
|
|
* made before satisfying the allocation
|
|
* MAP_NORESERVE mappings may also need pages and quota allocated
|
|
* if no reserve mapping overlaps.
|
|
*/
|
|
chg = vma_needs_reservation(h, vma, addr);
|
|
if (chg < 0)
|
|
return ERR_PTR(-VM_FAULT_OOM);
|
|
if (chg)
|
|
if (hugetlb_get_quota(inode->i_mapping, chg))
|
|
return ERR_PTR(-VM_FAULT_SIGBUS);
|
|
|
|
spin_lock(&hugetlb_lock);
|
|
page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve);
|
|
spin_unlock(&hugetlb_lock);
|
|
|
|
if (!page) {
|
|
page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
|
|
if (!page) {
|
|
hugetlb_put_quota(inode->i_mapping, chg);
|
|
return ERR_PTR(-VM_FAULT_SIGBUS);
|
|
}
|
|
}
|
|
|
|
set_page_private(page, (unsigned long) mapping);
|
|
|
|
vma_commit_reservation(h, vma, addr);
|
|
|
|
return page;
|
|
}
|
|
|
|
int __weak alloc_bootmem_huge_page(struct hstate *h)
|
|
{
|
|
struct huge_bootmem_page *m;
|
|
int nr_nodes = nodes_weight(node_states[N_HIGH_MEMORY]);
|
|
|
|
while (nr_nodes) {
|
|
void *addr;
|
|
|
|
addr = __alloc_bootmem_node_nopanic(
|
|
NODE_DATA(hstate_next_node_to_alloc(h,
|
|
&node_states[N_HIGH_MEMORY])),
|
|
huge_page_size(h), huge_page_size(h), 0);
|
|
|
|
if (addr) {
|
|
/*
|
|
* Use the beginning of the huge page to store the
|
|
* huge_bootmem_page struct (until gather_bootmem
|
|
* puts them into the mem_map).
|
|
*/
|
|
m = addr;
|
|
goto found;
|
|
}
|
|
nr_nodes--;
|
|
}
|
|
return 0;
|
|
|
|
found:
|
|
BUG_ON((unsigned long)virt_to_phys(m) & (huge_page_size(h) - 1));
|
|
/* Put them into a private list first because mem_map is not up yet */
|
|
list_add(&m->list, &huge_boot_pages);
|
|
m->hstate = h;
|
|
return 1;
|
|
}
|
|
|
|
static void prep_compound_huge_page(struct page *page, int order)
|
|
{
|
|
if (unlikely(order > (MAX_ORDER - 1)))
|
|
prep_compound_gigantic_page(page, order);
|
|
else
|
|
prep_compound_page(page, order);
|
|
}
|
|
|
|
/* Put bootmem huge pages into the standard lists after mem_map is up */
|
|
static void __init gather_bootmem_prealloc(void)
|
|
{
|
|
struct huge_bootmem_page *m;
|
|
|
|
list_for_each_entry(m, &huge_boot_pages, list) {
|
|
struct hstate *h = m->hstate;
|
|
struct page *page;
|
|
|
|
#ifdef CONFIG_HIGHMEM
|
|
page = pfn_to_page(m->phys >> PAGE_SHIFT);
|
|
free_bootmem_late((unsigned long)m,
|
|
sizeof(struct huge_bootmem_page));
|
|
#else
|
|
page = virt_to_page(m);
|
|
#endif
|
|
__ClearPageReserved(page);
|
|
WARN_ON(page_count(page) != 1);
|
|
prep_compound_huge_page(page, h->order);
|
|
prep_new_huge_page(h, page, page_to_nid(page));
|
|
/*
|
|
* If we had gigantic hugepages allocated at boot time, we need
|
|
* to restore the 'stolen' pages to totalram_pages in order to
|
|
* fix confusing memory reports from free(1) and another
|
|
* side-effects, like CommitLimit going negative.
|
|
*/
|
|
if (h->order > (MAX_ORDER - 1))
|
|
totalram_pages += 1 << h->order;
|
|
}
|
|
}
|
|
|
|
static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
|
|
{
|
|
unsigned long i;
|
|
|
|
for (i = 0; i < h->max_huge_pages; ++i) {
|
|
if (h->order >= MAX_ORDER) {
|
|
if (!alloc_bootmem_huge_page(h))
|
|
break;
|
|
} else if (!alloc_fresh_huge_page(h,
|
|
&node_states[N_HIGH_MEMORY]))
|
|
break;
|
|
}
|
|
h->max_huge_pages = i;
|
|
}
|
|
|
|
static void __init hugetlb_init_hstates(void)
|
|
{
|
|
struct hstate *h;
|
|
|
|
for_each_hstate(h) {
|
|
/* oversize hugepages were init'ed in early boot */
|
|
if (h->order < MAX_ORDER)
|
|
hugetlb_hstate_alloc_pages(h);
|
|
}
|
|
}
|
|
|
|
static char * __init memfmt(char *buf, unsigned long n)
|
|
{
|
|
if (n >= (1UL << 30))
|
|
sprintf(buf, "%lu GB", n >> 30);
|
|
else if (n >= (1UL << 20))
|
|
sprintf(buf, "%lu MB", n >> 20);
|
|
else
|
|
sprintf(buf, "%lu KB", n >> 10);
|
|
return buf;
|
|
}
|
|
|
|
static void __init report_hugepages(void)
|
|
{
|
|
struct hstate *h;
|
|
|
|
for_each_hstate(h) {
|
|
char buf[32];
|
|
printk(KERN_INFO "HugeTLB registered %s page size, "
|
|
"pre-allocated %ld pages\n",
|
|
memfmt(buf, huge_page_size(h)),
|
|
h->free_huge_pages);
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_HIGHMEM
|
|
static void try_to_free_low(struct hstate *h, unsigned long count,
|
|
nodemask_t *nodes_allowed)
|
|
{
|
|
int i;
|
|
|
|
if (h->order >= MAX_ORDER)
|
|
return;
|
|
|
|
for_each_node_mask(i, *nodes_allowed) {
|
|
struct page *page, *next;
|
|
struct list_head *freel = &h->hugepage_freelists[i];
|
|
list_for_each_entry_safe(page, next, freel, lru) {
|
|
if (count >= h->nr_huge_pages)
|
|
return;
|
|
if (PageHighMem(page))
|
|
continue;
|
|
list_del(&page->lru);
|
|
update_and_free_page(h, page);
|
|
h->free_huge_pages--;
|
|
h->free_huge_pages_node[page_to_nid(page)]--;
|
|
}
|
|
}
|
|
}
|
|
#else
|
|
static inline void try_to_free_low(struct hstate *h, unsigned long count,
|
|
nodemask_t *nodes_allowed)
|
|
{
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Increment or decrement surplus_huge_pages. Keep node-specific counters
|
|
* balanced by operating on them in a round-robin fashion.
|
|
* Returns 1 if an adjustment was made.
|
|
*/
|
|
static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
|
|
int delta)
|
|
{
|
|
int start_nid, next_nid;
|
|
int ret = 0;
|
|
|
|
VM_BUG_ON(delta != -1 && delta != 1);
|
|
|
|
if (delta < 0)
|
|
start_nid = hstate_next_node_to_alloc(h, nodes_allowed);
|
|
else
|
|
start_nid = hstate_next_node_to_free(h, nodes_allowed);
|
|
next_nid = start_nid;
|
|
|
|
do {
|
|
int nid = next_nid;
|
|
if (delta < 0) {
|
|
/*
|
|
* To shrink on this node, there must be a surplus page
|
|
*/
|
|
if (!h->surplus_huge_pages_node[nid]) {
|
|
next_nid = hstate_next_node_to_alloc(h,
|
|
nodes_allowed);
|
|
continue;
|
|
}
|
|
}
|
|
if (delta > 0) {
|
|
/*
|
|
* Surplus cannot exceed the total number of pages
|
|
*/
|
|
if (h->surplus_huge_pages_node[nid] >=
|
|
h->nr_huge_pages_node[nid]) {
|
|
next_nid = hstate_next_node_to_free(h,
|
|
nodes_allowed);
|
|
continue;
|
|
}
|
|
}
|
|
|
|
h->surplus_huge_pages += delta;
|
|
h->surplus_huge_pages_node[nid] += delta;
|
|
ret = 1;
|
|
break;
|
|
} while (next_nid != start_nid);
|
|
|
|
return ret;
|
|
}
|
|
|
|
#define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
|
|
static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count,
|
|
nodemask_t *nodes_allowed)
|
|
{
|
|
unsigned long min_count, ret;
|
|
|
|
if (h->order >= MAX_ORDER)
|
|
return h->max_huge_pages;
|
|
|
|
/*
|
|
* Increase the pool size
|
|
* First take pages out of surplus state. Then make up the
|
|
* remaining difference by allocating fresh huge pages.
|
|
*
|
|
* We might race with alloc_buddy_huge_page() here and be unable
|
|
* to convert a surplus huge page to a normal huge page. That is
|
|
* not critical, though, it just means the overall size of the
|
|
* pool might be one hugepage larger than it needs to be, but
|
|
* within all the constraints specified by the sysctls.
|
|
*/
|
|
spin_lock(&hugetlb_lock);
|
|
while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
|
|
if (!adjust_pool_surplus(h, nodes_allowed, -1))
|
|
break;
|
|
}
|
|
|
|
while (count > persistent_huge_pages(h)) {
|
|
/*
|
|
* If this allocation races such that we no longer need the
|
|
* page, free_huge_page will handle it by freeing the page
|
|
* and reducing the surplus.
|
|
*/
|
|
spin_unlock(&hugetlb_lock);
|
|
ret = alloc_fresh_huge_page(h, nodes_allowed);
|
|
spin_lock(&hugetlb_lock);
|
|
if (!ret)
|
|
goto out;
|
|
|
|
/* Bail for signals. Probably ctrl-c from user */
|
|
if (signal_pending(current))
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Decrease the pool size
|
|
* First return free pages to the buddy allocator (being careful
|
|
* to keep enough around to satisfy reservations). Then place
|
|
* pages into surplus state as needed so the pool will shrink
|
|
* to the desired size as pages become free.
|
|
*
|
|
* By placing pages into the surplus state independent of the
|
|
* overcommit value, we are allowing the surplus pool size to
|
|
* exceed overcommit. There are few sane options here. Since
|
|
* alloc_buddy_huge_page() is checking the global counter,
|
|
* though, we'll note that we're not allowed to exceed surplus
|
|
* and won't grow the pool anywhere else. Not until one of the
|
|
* sysctls are changed, or the surplus pages go out of use.
|
|
*/
|
|
min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
|
|
min_count = max(count, min_count);
|
|
try_to_free_low(h, min_count, nodes_allowed);
|
|
while (min_count < persistent_huge_pages(h)) {
|
|
if (!free_pool_huge_page(h, nodes_allowed, 0))
|
|
break;
|
|
}
|
|
while (count < persistent_huge_pages(h)) {
|
|
if (!adjust_pool_surplus(h, nodes_allowed, 1))
|
|
break;
|
|
}
|
|
out:
|
|
ret = persistent_huge_pages(h);
|
|
spin_unlock(&hugetlb_lock);
|
|
return ret;
|
|
}
|
|
|
|
#define HSTATE_ATTR_RO(_name) \
|
|
static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
|
|
|
|
#define HSTATE_ATTR(_name) \
|
|
static struct kobj_attribute _name##_attr = \
|
|
__ATTR(_name, 0644, _name##_show, _name##_store)
|
|
|
|
static struct kobject *hugepages_kobj;
|
|
static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
|
|
|
|
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
|
|
|
|
static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < HUGE_MAX_HSTATE; i++)
|
|
if (hstate_kobjs[i] == kobj) {
|
|
if (nidp)
|
|
*nidp = NUMA_NO_NODE;
|
|
return &hstates[i];
|
|
}
|
|
|
|
return kobj_to_node_hstate(kobj, nidp);
|
|
}
|
|
|
|
static ssize_t nr_hugepages_show_common(struct kobject *kobj,
|
|
struct kobj_attribute *attr, char *buf)
|
|
{
|
|
struct hstate *h;
|
|
unsigned long nr_huge_pages;
|
|
int nid;
|
|
|
|
h = kobj_to_hstate(kobj, &nid);
|
|
if (nid == NUMA_NO_NODE)
|
|
nr_huge_pages = h->nr_huge_pages;
|
|
else
|
|
nr_huge_pages = h->nr_huge_pages_node[nid];
|
|
|
|
return sprintf(buf, "%lu\n", nr_huge_pages);
|
|
}
|
|
|
|
static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
|
|
struct kobject *kobj, struct kobj_attribute *attr,
|
|
const char *buf, size_t len)
|
|
{
|
|
int err;
|
|
int nid;
|
|
unsigned long count;
|
|
struct hstate *h;
|
|
NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY);
|
|
|
|
err = strict_strtoul(buf, 10, &count);
|
|
if (err)
|
|
goto out;
|
|
|
|
h = kobj_to_hstate(kobj, &nid);
|
|
if (h->order >= MAX_ORDER) {
|
|
err = -EINVAL;
|
|
goto out;
|
|
}
|
|
|
|
if (nid == NUMA_NO_NODE) {
|
|
/*
|
|
* global hstate attribute
|
|
*/
|
|
if (!(obey_mempolicy &&
|
|
init_nodemask_of_mempolicy(nodes_allowed))) {
|
|
NODEMASK_FREE(nodes_allowed);
|
|
nodes_allowed = &node_states[N_HIGH_MEMORY];
|
|
}
|
|
} else if (nodes_allowed) {
|
|
/*
|
|
* per node hstate attribute: adjust count to global,
|
|
* but restrict alloc/free to the specified node.
|
|
*/
|
|
count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
|
|
init_nodemask_of_node(nodes_allowed, nid);
|
|
} else
|
|
nodes_allowed = &node_states[N_HIGH_MEMORY];
|
|
|
|
h->max_huge_pages = set_max_huge_pages(h, count, nodes_allowed);
|
|
|
|
if (nodes_allowed != &node_states[N_HIGH_MEMORY])
|
|
NODEMASK_FREE(nodes_allowed);
|
|
|
|
return len;
|
|
out:
|
|
NODEMASK_FREE(nodes_allowed);
|
|
return err;
|
|
}
|
|
|
|
static ssize_t nr_hugepages_show(struct kobject *kobj,
|
|
struct kobj_attribute *attr, char *buf)
|
|
{
|
|
return nr_hugepages_show_common(kobj, attr, buf);
|
|
}
|
|
|
|
static ssize_t nr_hugepages_store(struct kobject *kobj,
|
|
struct kobj_attribute *attr, const char *buf, size_t len)
|
|
{
|
|
return nr_hugepages_store_common(false, kobj, attr, buf, len);
|
|
}
|
|
HSTATE_ATTR(nr_hugepages);
|
|
|
|
#ifdef CONFIG_NUMA
|
|
|
|
/*
|
|
* hstate attribute for optionally mempolicy-based constraint on persistent
|
|
* huge page alloc/free.
|
|
*/
|
|
static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
|
|
struct kobj_attribute *attr, char *buf)
|
|
{
|
|
return nr_hugepages_show_common(kobj, attr, buf);
|
|
}
|
|
|
|
static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
|
|
struct kobj_attribute *attr, const char *buf, size_t len)
|
|
{
|
|
return nr_hugepages_store_common(true, kobj, attr, buf, len);
|
|
}
|
|
HSTATE_ATTR(nr_hugepages_mempolicy);
|
|
#endif
|
|
|
|
|
|
static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
|
|
struct kobj_attribute *attr, char *buf)
|
|
{
|
|
struct hstate *h = kobj_to_hstate(kobj, NULL);
|
|
return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
|
|
}
|
|
|
|
static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
|
|
struct kobj_attribute *attr, const char *buf, size_t count)
|
|
{
|
|
int err;
|
|
unsigned long input;
|
|
struct hstate *h = kobj_to_hstate(kobj, NULL);
|
|
|
|
if (h->order >= MAX_ORDER)
|
|
return -EINVAL;
|
|
|
|
err = strict_strtoul(buf, 10, &input);
|
|
if (err)
|
|
return err;
|
|
|
|
spin_lock(&hugetlb_lock);
|
|
h->nr_overcommit_huge_pages = input;
|
|
spin_unlock(&hugetlb_lock);
|
|
|
|
return count;
|
|
}
|
|
HSTATE_ATTR(nr_overcommit_hugepages);
|
|
|
|
static ssize_t free_hugepages_show(struct kobject *kobj,
|
|
struct kobj_attribute *attr, char *buf)
|
|
{
|
|
struct hstate *h;
|
|
unsigned long free_huge_pages;
|
|
int nid;
|
|
|
|
h = kobj_to_hstate(kobj, &nid);
|
|
if (nid == NUMA_NO_NODE)
|
|
free_huge_pages = h->free_huge_pages;
|
|
else
|
|
free_huge_pages = h->free_huge_pages_node[nid];
|
|
|
|
return sprintf(buf, "%lu\n", free_huge_pages);
|
|
}
|
|
HSTATE_ATTR_RO(free_hugepages);
|
|
|
|
static ssize_t resv_hugepages_show(struct kobject *kobj,
|
|
struct kobj_attribute *attr, char *buf)
|
|
{
|
|
struct hstate *h = kobj_to_hstate(kobj, NULL);
|
|
return sprintf(buf, "%lu\n", h->resv_huge_pages);
|
|
}
|
|
HSTATE_ATTR_RO(resv_hugepages);
|
|
|
|
static ssize_t surplus_hugepages_show(struct kobject *kobj,
|
|
struct kobj_attribute *attr, char *buf)
|
|
{
|
|
struct hstate *h;
|
|
unsigned long surplus_huge_pages;
|
|
int nid;
|
|
|
|
h = kobj_to_hstate(kobj, &nid);
|
|
if (nid == NUMA_NO_NODE)
|
|
surplus_huge_pages = h->surplus_huge_pages;
|
|
else
|
|
surplus_huge_pages = h->surplus_huge_pages_node[nid];
|
|
|
|
return sprintf(buf, "%lu\n", surplus_huge_pages);
|
|
}
|
|
HSTATE_ATTR_RO(surplus_hugepages);
|
|
|
|
static struct attribute *hstate_attrs[] = {
|
|
&nr_hugepages_attr.attr,
|
|
&nr_overcommit_hugepages_attr.attr,
|
|
&free_hugepages_attr.attr,
|
|
&resv_hugepages_attr.attr,
|
|
&surplus_hugepages_attr.attr,
|
|
#ifdef CONFIG_NUMA
|
|
&nr_hugepages_mempolicy_attr.attr,
|
|
#endif
|
|
NULL,
|
|
};
|
|
|
|
static struct attribute_group hstate_attr_group = {
|
|
.attrs = hstate_attrs,
|
|
};
|
|
|
|
static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
|
|
struct kobject **hstate_kobjs,
|
|
struct attribute_group *hstate_attr_group)
|
|
{
|
|
int retval;
|
|
int hi = h - hstates;
|
|
|
|
hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
|
|
if (!hstate_kobjs[hi])
|
|
return -ENOMEM;
|
|
|
|
retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
|
|
if (retval)
|
|
kobject_put(hstate_kobjs[hi]);
|
|
|
|
return retval;
|
|
}
|
|
|
|
static void __init hugetlb_sysfs_init(void)
|
|
{
|
|
struct hstate *h;
|
|
int err;
|
|
|
|
hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
|
|
if (!hugepages_kobj)
|
|
return;
|
|
|
|
for_each_hstate(h) {
|
|
err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
|
|
hstate_kobjs, &hstate_attr_group);
|
|
if (err)
|
|
printk(KERN_ERR "Hugetlb: Unable to add hstate %s",
|
|
h->name);
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_NUMA
|
|
|
|
/*
|
|
* node_hstate/s - associate per node hstate attributes, via their kobjects,
|
|
* with node devices in node_devices[] using a parallel array. The array
|
|
* index of a node device or _hstate == node id.
|
|
* This is here to avoid any static dependency of the node device driver, in
|
|
* the base kernel, on the hugetlb module.
|
|
*/
|
|
struct node_hstate {
|
|
struct kobject *hugepages_kobj;
|
|
struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
|
|
};
|
|
struct node_hstate node_hstates[MAX_NUMNODES];
|
|
|
|
/*
|
|
* A subset of global hstate attributes for node devices
|
|
*/
|
|
static struct attribute *per_node_hstate_attrs[] = {
|
|
&nr_hugepages_attr.attr,
|
|
&free_hugepages_attr.attr,
|
|
&surplus_hugepages_attr.attr,
|
|
NULL,
|
|
};
|
|
|
|
static struct attribute_group per_node_hstate_attr_group = {
|
|
.attrs = per_node_hstate_attrs,
|
|
};
|
|
|
|
/*
|
|
* kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
|
|
* Returns node id via non-NULL nidp.
|
|
*/
|
|
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
|
|
{
|
|
int nid;
|
|
|
|
for (nid = 0; nid < nr_node_ids; nid++) {
|
|
struct node_hstate *nhs = &node_hstates[nid];
|
|
int i;
|
|
for (i = 0; i < HUGE_MAX_HSTATE; i++)
|
|
if (nhs->hstate_kobjs[i] == kobj) {
|
|
if (nidp)
|
|
*nidp = nid;
|
|
return &hstates[i];
|
|
}
|
|
}
|
|
|
|
BUG();
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Unregister hstate attributes from a single node device.
|
|
* No-op if no hstate attributes attached.
|
|
*/
|
|
void hugetlb_unregister_node(struct node *node)
|
|
{
|
|
struct hstate *h;
|
|
struct node_hstate *nhs = &node_hstates[node->dev.id];
|
|
|
|
if (!nhs->hugepages_kobj)
|
|
return; /* no hstate attributes */
|
|
|
|
for_each_hstate(h)
|
|
if (nhs->hstate_kobjs[h - hstates]) {
|
|
kobject_put(nhs->hstate_kobjs[h - hstates]);
|
|
nhs->hstate_kobjs[h - hstates] = NULL;
|
|
}
|
|
|
|
kobject_put(nhs->hugepages_kobj);
|
|
nhs->hugepages_kobj = NULL;
|
|
}
|
|
|
|
/*
|
|
* hugetlb module exit: unregister hstate attributes from node devices
|
|
* that have them.
|
|
*/
|
|
static void hugetlb_unregister_all_nodes(void)
|
|
{
|
|
int nid;
|
|
|
|
/*
|
|
* disable node device registrations.
|
|
*/
|
|
register_hugetlbfs_with_node(NULL, NULL);
|
|
|
|
/*
|
|
* remove hstate attributes from any nodes that have them.
|
|
*/
|
|
for (nid = 0; nid < nr_node_ids; nid++)
|
|
hugetlb_unregister_node(&node_devices[nid]);
|
|
}
|
|
|
|
/*
|
|
* Register hstate attributes for a single node device.
|
|
* No-op if attributes already registered.
|
|
*/
|
|
void hugetlb_register_node(struct node *node)
|
|
{
|
|
struct hstate *h;
|
|
struct node_hstate *nhs = &node_hstates[node->dev.id];
|
|
int err;
|
|
|
|
if (nhs->hugepages_kobj)
|
|
return; /* already allocated */
|
|
|
|
nhs->hugepages_kobj = kobject_create_and_add("hugepages",
|
|
&node->dev.kobj);
|
|
if (!nhs->hugepages_kobj)
|
|
return;
|
|
|
|
for_each_hstate(h) {
|
|
err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
|
|
nhs->hstate_kobjs,
|
|
&per_node_hstate_attr_group);
|
|
if (err) {
|
|
printk(KERN_ERR "Hugetlb: Unable to add hstate %s"
|
|
" for node %d\n",
|
|
h->name, node->dev.id);
|
|
hugetlb_unregister_node(node);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* hugetlb init time: register hstate attributes for all registered node
|
|
* devices of nodes that have memory. All on-line nodes should have
|
|
* registered their associated device by this time.
|
|
*/
|
|
static void hugetlb_register_all_nodes(void)
|
|
{
|
|
int nid;
|
|
|
|
for_each_node_state(nid, N_HIGH_MEMORY) {
|
|
struct node *node = &node_devices[nid];
|
|
if (node->dev.id == nid)
|
|
hugetlb_register_node(node);
|
|
}
|
|
|
|
/*
|
|
* Let the node device driver know we're here so it can
|
|
* [un]register hstate attributes on node hotplug.
|
|
*/
|
|
register_hugetlbfs_with_node(hugetlb_register_node,
|
|
hugetlb_unregister_node);
|
|
}
|
|
#else /* !CONFIG_NUMA */
|
|
|
|
static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
|
|
{
|
|
BUG();
|
|
if (nidp)
|
|
*nidp = -1;
|
|
return NULL;
|
|
}
|
|
|
|
static void hugetlb_unregister_all_nodes(void) { }
|
|
|
|
static void hugetlb_register_all_nodes(void) { }
|
|
|
|
#endif
|
|
|
|
static void __exit hugetlb_exit(void)
|
|
{
|
|
struct hstate *h;
|
|
|
|
hugetlb_unregister_all_nodes();
|
|
|
|
for_each_hstate(h) {
|
|
kobject_put(hstate_kobjs[h - hstates]);
|
|
}
|
|
|
|
kobject_put(hugepages_kobj);
|
|
}
|
|
module_exit(hugetlb_exit);
|
|
|
|
static int __init hugetlb_init(void)
|
|
{
|
|
/* Some platform decide whether they support huge pages at boot
|
|
* time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
|
|
* there is no such support
|
|
*/
|
|
if (HPAGE_SHIFT == 0)
|
|
return 0;
|
|
|
|
if (!size_to_hstate(default_hstate_size)) {
|
|
default_hstate_size = HPAGE_SIZE;
|
|
if (!size_to_hstate(default_hstate_size))
|
|
hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
|
|
}
|
|
default_hstate_idx = size_to_hstate(default_hstate_size) - hstates;
|
|
if (default_hstate_max_huge_pages)
|
|
default_hstate.max_huge_pages = default_hstate_max_huge_pages;
|
|
|
|
hugetlb_init_hstates();
|
|
|
|
gather_bootmem_prealloc();
|
|
|
|
report_hugepages();
|
|
|
|
hugetlb_sysfs_init();
|
|
|
|
hugetlb_register_all_nodes();
|
|
|
|
return 0;
|
|
}
|
|
module_init(hugetlb_init);
|
|
|
|
/* Should be called on processing a hugepagesz=... option */
|
|
void __init hugetlb_add_hstate(unsigned order)
|
|
{
|
|
struct hstate *h;
|
|
unsigned long i;
|
|
|
|
if (size_to_hstate(PAGE_SIZE << order)) {
|
|
printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n");
|
|
return;
|
|
}
|
|
BUG_ON(max_hstate >= HUGE_MAX_HSTATE);
|
|
BUG_ON(order == 0);
|
|
h = &hstates[max_hstate++];
|
|
h->order = order;
|
|
h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
|
|
h->nr_huge_pages = 0;
|
|
h->free_huge_pages = 0;
|
|
for (i = 0; i < MAX_NUMNODES; ++i)
|
|
INIT_LIST_HEAD(&h->hugepage_freelists[i]);
|
|
h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]);
|
|
h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]);
|
|
snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
|
|
huge_page_size(h)/1024);
|
|
|
|
parsed_hstate = h;
|
|
}
|
|
|
|
static int __init hugetlb_nrpages_setup(char *s)
|
|
{
|
|
unsigned long *mhp;
|
|
static unsigned long *last_mhp;
|
|
|
|
/*
|
|
* !max_hstate means we haven't parsed a hugepagesz= parameter yet,
|
|
* so this hugepages= parameter goes to the "default hstate".
|
|
*/
|
|
if (!max_hstate)
|
|
mhp = &default_hstate_max_huge_pages;
|
|
else
|
|
mhp = &parsed_hstate->max_huge_pages;
|
|
|
|
if (mhp == last_mhp) {
|
|
printk(KERN_WARNING "hugepages= specified twice without "
|
|
"interleaving hugepagesz=, ignoring\n");
|
|
return 1;
|
|
}
|
|
|
|
if (sscanf(s, "%lu", mhp) <= 0)
|
|
*mhp = 0;
|
|
|
|
/*
|
|
* Global state is always initialized later in hugetlb_init.
|
|
* But we need to allocate >= MAX_ORDER hstates here early to still
|
|
* use the bootmem allocator.
|
|
*/
|
|
if (max_hstate && parsed_hstate->order >= MAX_ORDER)
|
|
hugetlb_hstate_alloc_pages(parsed_hstate);
|
|
|
|
last_mhp = mhp;
|
|
|
|
return 1;
|
|
}
|
|
__setup("hugepages=", hugetlb_nrpages_setup);
|
|
|
|
static int __init hugetlb_default_setup(char *s)
|
|
{
|
|
default_hstate_size = memparse(s, &s);
|
|
return 1;
|
|
}
|
|
__setup("default_hugepagesz=", hugetlb_default_setup);
|
|
|
|
static unsigned int cpuset_mems_nr(unsigned int *array)
|
|
{
|
|
int node;
|
|
unsigned int nr = 0;
|
|
|
|
for_each_node_mask(node, cpuset_current_mems_allowed)
|
|
nr += array[node];
|
|
|
|
return nr;
|
|
}
|
|
|
|
#ifdef CONFIG_SYSCTL
|
|
static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
|
|
struct ctl_table *table, int write,
|
|
void __user *buffer, size_t *length, loff_t *ppos)
|
|
{
|
|
struct hstate *h = &default_hstate;
|
|
unsigned long tmp;
|
|
int ret;
|
|
|
|
tmp = h->max_huge_pages;
|
|
|
|
if (write && h->order >= MAX_ORDER)
|
|
return -EINVAL;
|
|
|
|
table->data = &tmp;
|
|
table->maxlen = sizeof(unsigned long);
|
|
ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
|
|
if (ret)
|
|
goto out;
|
|
|
|
if (write) {
|
|
NODEMASK_ALLOC(nodemask_t, nodes_allowed,
|
|
GFP_KERNEL | __GFP_NORETRY);
|
|
if (!(obey_mempolicy &&
|
|
init_nodemask_of_mempolicy(nodes_allowed))) {
|
|
NODEMASK_FREE(nodes_allowed);
|
|
nodes_allowed = &node_states[N_HIGH_MEMORY];
|
|
}
|
|
h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed);
|
|
|
|
if (nodes_allowed != &node_states[N_HIGH_MEMORY])
|
|
NODEMASK_FREE(nodes_allowed);
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
|
|
void __user *buffer, size_t *length, loff_t *ppos)
|
|
{
|
|
|
|
return hugetlb_sysctl_handler_common(false, table, write,
|
|
buffer, length, ppos);
|
|
}
|
|
|
|
#ifdef CONFIG_NUMA
|
|
int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
|
|
void __user *buffer, size_t *length, loff_t *ppos)
|
|
{
|
|
return hugetlb_sysctl_handler_common(true, table, write,
|
|
buffer, length, ppos);
|
|
}
|
|
#endif /* CONFIG_NUMA */
|
|
|
|
int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
|
|
void __user *buffer,
|
|
size_t *length, loff_t *ppos)
|
|
{
|
|
proc_dointvec(table, write, buffer, length, ppos);
|
|
if (hugepages_treat_as_movable)
|
|
htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
|
|
else
|
|
htlb_alloc_mask = GFP_HIGHUSER;
|
|
return 0;
|
|
}
|
|
|
|
int hugetlb_overcommit_handler(struct ctl_table *table, int write,
|
|
void __user *buffer,
|
|
size_t *length, loff_t *ppos)
|
|
{
|
|
struct hstate *h = &default_hstate;
|
|
unsigned long tmp;
|
|
int ret;
|
|
|
|
tmp = h->nr_overcommit_huge_pages;
|
|
|
|
if (write && h->order >= MAX_ORDER)
|
|
return -EINVAL;
|
|
|
|
table->data = &tmp;
|
|
table->maxlen = sizeof(unsigned long);
|
|
ret = proc_doulongvec_minmax(table, write, buffer, length, ppos);
|
|
if (ret)
|
|
goto out;
|
|
|
|
if (write) {
|
|
spin_lock(&hugetlb_lock);
|
|
h->nr_overcommit_huge_pages = tmp;
|
|
spin_unlock(&hugetlb_lock);
|
|
}
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
#endif /* CONFIG_SYSCTL */
|
|
|
|
void hugetlb_report_meminfo(struct seq_file *m)
|
|
{
|
|
struct hstate *h = &default_hstate;
|
|
seq_printf(m,
|
|
"HugePages_Total: %5lu\n"
|
|
"HugePages_Free: %5lu\n"
|
|
"HugePages_Rsvd: %5lu\n"
|
|
"HugePages_Surp: %5lu\n"
|
|
"Hugepagesize: %8lu kB\n",
|
|
h->nr_huge_pages,
|
|
h->free_huge_pages,
|
|
h->resv_huge_pages,
|
|
h->surplus_huge_pages,
|
|
1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
|
|
}
|
|
|
|
int hugetlb_report_node_meminfo(int nid, char *buf)
|
|
{
|
|
struct hstate *h = &default_hstate;
|
|
return sprintf(buf,
|
|
"Node %d HugePages_Total: %5u\n"
|
|
"Node %d HugePages_Free: %5u\n"
|
|
"Node %d HugePages_Surp: %5u\n",
|
|
nid, h->nr_huge_pages_node[nid],
|
|
nid, h->free_huge_pages_node[nid],
|
|
nid, h->surplus_huge_pages_node[nid]);
|
|
}
|
|
|
|
/* Return the number pages of memory we physically have, in PAGE_SIZE units. */
|
|
unsigned long hugetlb_total_pages(void)
|
|
{
|
|
struct hstate *h = &default_hstate;
|
|
return h->nr_huge_pages * pages_per_huge_page(h);
|
|
}
|
|
|
|
static int hugetlb_acct_memory(struct hstate *h, long delta)
|
|
{
|
|
int ret = -ENOMEM;
|
|
|
|
spin_lock(&hugetlb_lock);
|
|
/*
|
|
* When cpuset is configured, it breaks the strict hugetlb page
|
|
* reservation as the accounting is done on a global variable. Such
|
|
* reservation is completely rubbish in the presence of cpuset because
|
|
* the reservation is not checked against page availability for the
|
|
* current cpuset. Application can still potentially OOM'ed by kernel
|
|
* with lack of free htlb page in cpuset that the task is in.
|
|
* Attempt to enforce strict accounting with cpuset is almost
|
|
* impossible (or too ugly) because cpuset is too fluid that
|
|
* task or memory node can be dynamically moved between cpusets.
|
|
*
|
|
* The change of semantics for shared hugetlb mapping with cpuset is
|
|
* undesirable. However, in order to preserve some of the semantics,
|
|
* we fall back to check against current free page availability as
|
|
* a best attempt and hopefully to minimize the impact of changing
|
|
* semantics that cpuset has.
|
|
*/
|
|
if (delta > 0) {
|
|
if (gather_surplus_pages(h, delta) < 0)
|
|
goto out;
|
|
|
|
if (delta > cpuset_mems_nr(h->free_huge_pages_node)) {
|
|
return_unused_surplus_pages(h, delta);
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
ret = 0;
|
|
if (delta < 0)
|
|
return_unused_surplus_pages(h, (unsigned long) -delta);
|
|
|
|
out:
|
|
spin_unlock(&hugetlb_lock);
|
|
return ret;
|
|
}
|
|
|
|
static void hugetlb_vm_op_open(struct vm_area_struct *vma)
|
|
{
|
|
struct resv_map *reservations = vma_resv_map(vma);
|
|
|
|
/*
|
|
* This new VMA should share its siblings reservation map if present.
|
|
* The VMA will only ever have a valid reservation map pointer where
|
|
* it is being copied for another still existing VMA. As that VMA
|
|
* has a reference to the reservation map it cannot disappear until
|
|
* after this open call completes. It is therefore safe to take a
|
|
* new reference here without additional locking.
|
|
*/
|
|
if (reservations)
|
|
kref_get(&reservations->refs);
|
|
}
|
|
|
|
static void hugetlb_vm_op_close(struct vm_area_struct *vma)
|
|
{
|
|
struct hstate *h = hstate_vma(vma);
|
|
struct resv_map *reservations = vma_resv_map(vma);
|
|
unsigned long reserve;
|
|
unsigned long start;
|
|
unsigned long end;
|
|
|
|
if (reservations) {
|
|
start = vma_hugecache_offset(h, vma, vma->vm_start);
|
|
end = vma_hugecache_offset(h, vma, vma->vm_end);
|
|
|
|
reserve = (end - start) -
|
|
region_count(&reservations->regions, start, end);
|
|
|
|
kref_put(&reservations->refs, resv_map_release);
|
|
|
|
if (reserve) {
|
|
hugetlb_acct_memory(h, -reserve);
|
|
hugetlb_put_quota(vma->vm_file->f_mapping, reserve);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We cannot handle pagefaults against hugetlb pages at all. They cause
|
|
* handle_mm_fault() to try to instantiate regular-sized pages in the
|
|
* hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
|
|
* this far.
|
|
*/
|
|
static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
{
|
|
BUG();
|
|
return 0;
|
|
}
|
|
|
|
const struct vm_operations_struct hugetlb_vm_ops = {
|
|
.fault = hugetlb_vm_op_fault,
|
|
.open = hugetlb_vm_op_open,
|
|
.close = hugetlb_vm_op_close,
|
|
};
|
|
|
|
static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
|
|
int writable)
|
|
{
|
|
pte_t entry;
|
|
|
|
if (writable) {
|
|
entry =
|
|
pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot)));
|
|
} else {
|
|
entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot));
|
|
}
|
|
entry = pte_mkyoung(entry);
|
|
entry = pte_mkhuge(entry);
|
|
|
|
return entry;
|
|
}
|
|
|
|
static void set_huge_ptep_writable(struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *ptep)
|
|
{
|
|
pte_t entry;
|
|
|
|
entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep)));
|
|
if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
|
|
update_mmu_cache(vma, address, ptep);
|
|
}
|
|
|
|
|
|
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
|
|
struct vm_area_struct *vma)
|
|
{
|
|
pte_t *src_pte, *dst_pte, entry;
|
|
struct page *ptepage;
|
|
unsigned long addr;
|
|
int cow;
|
|
struct hstate *h = hstate_vma(vma);
|
|
unsigned long sz = huge_page_size(h);
|
|
|
|
cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
|
|
|
|
for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
|
|
src_pte = huge_pte_offset(src, addr);
|
|
if (!src_pte)
|
|
continue;
|
|
dst_pte = huge_pte_alloc(dst, addr, sz);
|
|
if (!dst_pte)
|
|
goto nomem;
|
|
|
|
/* If the pagetables are shared don't copy or take references */
|
|
if (dst_pte == src_pte)
|
|
continue;
|
|
|
|
spin_lock(&dst->page_table_lock);
|
|
spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING);
|
|
if (!huge_pte_none(huge_ptep_get(src_pte))) {
|
|
if (cow)
|
|
huge_ptep_set_wrprotect(src, addr, src_pte);
|
|
entry = huge_ptep_get(src_pte);
|
|
ptepage = pte_page(entry);
|
|
get_page(ptepage);
|
|
page_dup_rmap(ptepage);
|
|
set_huge_pte_at(dst, addr, dst_pte, entry);
|
|
}
|
|
spin_unlock(&src->page_table_lock);
|
|
spin_unlock(&dst->page_table_lock);
|
|
}
|
|
return 0;
|
|
|
|
nomem:
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static int is_hugetlb_entry_migration(pte_t pte)
|
|
{
|
|
swp_entry_t swp;
|
|
|
|
if (huge_pte_none(pte) || pte_present(pte))
|
|
return 0;
|
|
swp = pte_to_swp_entry(pte);
|
|
if (non_swap_entry(swp) && is_migration_entry(swp))
|
|
return 1;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
static int is_hugetlb_entry_hwpoisoned(pte_t pte)
|
|
{
|
|
swp_entry_t swp;
|
|
|
|
if (huge_pte_none(pte) || pte_present(pte))
|
|
return 0;
|
|
swp = pte_to_swp_entry(pte);
|
|
if (non_swap_entry(swp) && is_hwpoison_entry(swp))
|
|
return 1;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
|
|
unsigned long end, struct page *ref_page)
|
|
{
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
unsigned long address;
|
|
pte_t *ptep;
|
|
pte_t pte;
|
|
struct page *page;
|
|
struct page *tmp;
|
|
struct hstate *h = hstate_vma(vma);
|
|
unsigned long sz = huge_page_size(h);
|
|
|
|
/*
|
|
* A page gathering list, protected by per file i_mmap_mutex. The
|
|
* lock is used to avoid list corruption from multiple unmapping
|
|
* of the same page since we are using page->lru.
|
|
*/
|
|
LIST_HEAD(page_list);
|
|
|
|
WARN_ON(!is_vm_hugetlb_page(vma));
|
|
BUG_ON(start & ~huge_page_mask(h));
|
|
BUG_ON(end & ~huge_page_mask(h));
|
|
|
|
mmu_notifier_invalidate_range_start(mm, start, end);
|
|
spin_lock(&mm->page_table_lock);
|
|
for (address = start; address < end; address += sz) {
|
|
ptep = huge_pte_offset(mm, address);
|
|
if (!ptep)
|
|
continue;
|
|
|
|
if (huge_pmd_unshare(mm, &address, ptep))
|
|
continue;
|
|
|
|
/*
|
|
* If a reference page is supplied, it is because a specific
|
|
* page is being unmapped, not a range. Ensure the page we
|
|
* are about to unmap is the actual page of interest.
|
|
*/
|
|
if (ref_page) {
|
|
pte = huge_ptep_get(ptep);
|
|
if (huge_pte_none(pte))
|
|
continue;
|
|
page = pte_page(pte);
|
|
if (page != ref_page)
|
|
continue;
|
|
|
|
/*
|
|
* Mark the VMA as having unmapped its page so that
|
|
* future faults in this VMA will fail rather than
|
|
* looking like data was lost
|
|
*/
|
|
set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
|
|
}
|
|
|
|
pte = huge_ptep_get_and_clear(mm, address, ptep);
|
|
if (huge_pte_none(pte))
|
|
continue;
|
|
|
|
/*
|
|
* HWPoisoned hugepage is already unmapped and dropped reference
|
|
*/
|
|
if (unlikely(is_hugetlb_entry_hwpoisoned(pte)))
|
|
continue;
|
|
|
|
page = pte_page(pte);
|
|
if (pte_dirty(pte))
|
|
set_page_dirty(page);
|
|
list_add(&page->lru, &page_list);
|
|
}
|
|
flush_tlb_range(vma, start, end);
|
|
spin_unlock(&mm->page_table_lock);
|
|
mmu_notifier_invalidate_range_end(mm, start, end);
|
|
list_for_each_entry_safe(page, tmp, &page_list, lru) {
|
|
page_remove_rmap(page);
|
|
list_del(&page->lru);
|
|
put_page(page);
|
|
}
|
|
}
|
|
|
|
void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
|
|
unsigned long end, struct page *ref_page)
|
|
{
|
|
mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
|
|
__unmap_hugepage_range(vma, start, end, ref_page);
|
|
mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
|
|
}
|
|
|
|
/*
|
|
* This is called when the original mapper is failing to COW a MAP_PRIVATE
|
|
* mappping it owns the reserve page for. The intention is to unmap the page
|
|
* from other VMAs and let the children be SIGKILLed if they are faulting the
|
|
* same region.
|
|
*/
|
|
static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
struct page *page, unsigned long address)
|
|
{
|
|
struct hstate *h = hstate_vma(vma);
|
|
struct vm_area_struct *iter_vma;
|
|
struct address_space *mapping;
|
|
struct prio_tree_iter iter;
|
|
pgoff_t pgoff;
|
|
|
|
/*
|
|
* vm_pgoff is in PAGE_SIZE units, hence the different calculation
|
|
* from page cache lookup which is in HPAGE_SIZE units.
|
|
*/
|
|
address = address & huge_page_mask(h);
|
|
pgoff = vma_hugecache_offset(h, vma, address);
|
|
mapping = (struct address_space *)page_private(page);
|
|
|
|
/*
|
|
* Take the mapping lock for the duration of the table walk. As
|
|
* this mapping should be shared between all the VMAs,
|
|
* __unmap_hugepage_range() is called as the lock is already held
|
|
*/
|
|
mutex_lock(&mapping->i_mmap_mutex);
|
|
vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
|
|
/* Do not unmap the current VMA */
|
|
if (iter_vma == vma)
|
|
continue;
|
|
|
|
/*
|
|
* Unmap the page from other VMAs without their own reserves.
|
|
* They get marked to be SIGKILLed if they fault in these
|
|
* areas. This is because a future no-page fault on this VMA
|
|
* could insert a zeroed page instead of the data existing
|
|
* from the time of fork. This would look like data corruption
|
|
*/
|
|
if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
|
|
__unmap_hugepage_range(iter_vma,
|
|
address, address + huge_page_size(h),
|
|
page);
|
|
}
|
|
mutex_unlock(&mapping->i_mmap_mutex);
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Hugetlb_cow() should be called with page lock of the original hugepage held.
|
|
* Called with hugetlb_instantiation_mutex held and pte_page locked so we
|
|
* cannot race with other handlers or page migration.
|
|
* Keep the pte_same checks anyway to make transition from the mutex easier.
|
|
*/
|
|
static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *ptep, pte_t pte,
|
|
struct page *pagecache_page)
|
|
{
|
|
struct hstate *h = hstate_vma(vma);
|
|
struct page *old_page, *new_page;
|
|
int avoidcopy;
|
|
int outside_reserve = 0;
|
|
|
|
old_page = pte_page(pte);
|
|
|
|
retry_avoidcopy:
|
|
/* If no-one else is actually using this page, avoid the copy
|
|
* and just make the page writable */
|
|
avoidcopy = (page_mapcount(old_page) == 1);
|
|
if (avoidcopy) {
|
|
if (PageAnon(old_page))
|
|
page_move_anon_rmap(old_page, vma, address);
|
|
set_huge_ptep_writable(vma, address, ptep);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* If the process that created a MAP_PRIVATE mapping is about to
|
|
* perform a COW due to a shared page count, attempt to satisfy
|
|
* the allocation without using the existing reserves. The pagecache
|
|
* page is used to determine if the reserve at this address was
|
|
* consumed or not. If reserves were used, a partial faulted mapping
|
|
* at the time of fork() could consume its reserves on COW instead
|
|
* of the full address range.
|
|
*/
|
|
if (!(vma->vm_flags & VM_MAYSHARE) &&
|
|
is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
|
|
old_page != pagecache_page)
|
|
outside_reserve = 1;
|
|
|
|
page_cache_get(old_page);
|
|
|
|
/* Drop page_table_lock as buddy allocator may be called */
|
|
spin_unlock(&mm->page_table_lock);
|
|
new_page = alloc_huge_page(vma, address, outside_reserve);
|
|
|
|
if (IS_ERR(new_page)) {
|
|
page_cache_release(old_page);
|
|
|
|
/*
|
|
* If a process owning a MAP_PRIVATE mapping fails to COW,
|
|
* it is due to references held by a child and an insufficient
|
|
* huge page pool. To guarantee the original mappers
|
|
* reliability, unmap the page from child processes. The child
|
|
* may get SIGKILLed if it later faults.
|
|
*/
|
|
if (outside_reserve) {
|
|
BUG_ON(huge_pte_none(pte));
|
|
if (unmap_ref_private(mm, vma, old_page, address)) {
|
|
BUG_ON(page_count(old_page) != 1);
|
|
BUG_ON(huge_pte_none(pte));
|
|
spin_lock(&mm->page_table_lock);
|
|
ptep = huge_pte_offset(mm, address & huge_page_mask(h));
|
|
if (likely(pte_same(huge_ptep_get(ptep), pte)))
|
|
goto retry_avoidcopy;
|
|
/*
|
|
* race occurs while re-acquiring page_table_lock, and
|
|
* our job is done.
|
|
*/
|
|
return 0;
|
|
}
|
|
WARN_ON_ONCE(1);
|
|
}
|
|
|
|
/* Caller expects lock to be held */
|
|
spin_lock(&mm->page_table_lock);
|
|
return -PTR_ERR(new_page);
|
|
}
|
|
|
|
/*
|
|
* When the original hugepage is shared one, it does not have
|
|
* anon_vma prepared.
|
|
*/
|
|
if (unlikely(anon_vma_prepare(vma))) {
|
|
page_cache_release(new_page);
|
|
page_cache_release(old_page);
|
|
/* Caller expects lock to be held */
|
|
spin_lock(&mm->page_table_lock);
|
|
return VM_FAULT_OOM;
|
|
}
|
|
|
|
copy_user_huge_page(new_page, old_page, address, vma,
|
|
pages_per_huge_page(h));
|
|
__SetPageUptodate(new_page);
|
|
|
|
/*
|
|
* Retake the page_table_lock to check for racing updates
|
|
* before the page tables are altered
|
|
*/
|
|
spin_lock(&mm->page_table_lock);
|
|
ptep = huge_pte_offset(mm, address & huge_page_mask(h));
|
|
if (likely(pte_same(huge_ptep_get(ptep), pte))) {
|
|
/* Break COW */
|
|
mmu_notifier_invalidate_range_start(mm,
|
|
address & huge_page_mask(h),
|
|
(address & huge_page_mask(h)) + huge_page_size(h));
|
|
huge_ptep_clear_flush(vma, address, ptep);
|
|
set_huge_pte_at(mm, address, ptep,
|
|
make_huge_pte(vma, new_page, 1));
|
|
page_remove_rmap(old_page);
|
|
hugepage_add_new_anon_rmap(new_page, vma, address);
|
|
/* Make the old page be freed below */
|
|
new_page = old_page;
|
|
mmu_notifier_invalidate_range_end(mm,
|
|
address & huge_page_mask(h),
|
|
(address & huge_page_mask(h)) + huge_page_size(h));
|
|
}
|
|
page_cache_release(new_page);
|
|
page_cache_release(old_page);
|
|
return 0;
|
|
}
|
|
|
|
/* Return the pagecache page at a given address within a VMA */
|
|
static struct page *hugetlbfs_pagecache_page(struct hstate *h,
|
|
struct vm_area_struct *vma, unsigned long address)
|
|
{
|
|
struct address_space *mapping;
|
|
pgoff_t idx;
|
|
|
|
mapping = vma->vm_file->f_mapping;
|
|
idx = vma_hugecache_offset(h, vma, address);
|
|
|
|
return find_lock_page(mapping, idx);
|
|
}
|
|
|
|
/*
|
|
* Return whether there is a pagecache page to back given address within VMA.
|
|
* Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
|
|
*/
|
|
static bool hugetlbfs_pagecache_present(struct hstate *h,
|
|
struct vm_area_struct *vma, unsigned long address)
|
|
{
|
|
struct address_space *mapping;
|
|
pgoff_t idx;
|
|
struct page *page;
|
|
|
|
mapping = vma->vm_file->f_mapping;
|
|
idx = vma_hugecache_offset(h, vma, address);
|
|
|
|
page = find_get_page(mapping, idx);
|
|
if (page)
|
|
put_page(page);
|
|
return page != NULL;
|
|
}
|
|
|
|
static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *ptep, unsigned int flags)
|
|
{
|
|
struct hstate *h = hstate_vma(vma);
|
|
int ret = VM_FAULT_SIGBUS;
|
|
int anon_rmap = 0;
|
|
pgoff_t idx;
|
|
unsigned long size;
|
|
struct page *page;
|
|
struct address_space *mapping;
|
|
pte_t new_pte;
|
|
|
|
/*
|
|
* Currently, we are forced to kill the process in the event the
|
|
* original mapper has unmapped pages from the child due to a failed
|
|
* COW. Warn that such a situation has occurred as it may not be obvious
|
|
*/
|
|
if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
|
|
printk(KERN_WARNING
|
|
"PID %d killed due to inadequate hugepage pool\n",
|
|
current->pid);
|
|
return ret;
|
|
}
|
|
|
|
mapping = vma->vm_file->f_mapping;
|
|
idx = vma_hugecache_offset(h, vma, address);
|
|
|
|
/*
|
|
* Use page lock to guard against racing truncation
|
|
* before we get page_table_lock.
|
|
*/
|
|
retry:
|
|
page = find_lock_page(mapping, idx);
|
|
if (!page) {
|
|
size = i_size_read(mapping->host) >> huge_page_shift(h);
|
|
if (idx >= size)
|
|
goto out;
|
|
page = alloc_huge_page(vma, address, 0);
|
|
if (IS_ERR(page)) {
|
|
ret = -PTR_ERR(page);
|
|
goto out;
|
|
}
|
|
clear_huge_page(page, address, pages_per_huge_page(h));
|
|
__SetPageUptodate(page);
|
|
|
|
if (vma->vm_flags & VM_MAYSHARE) {
|
|
int err;
|
|
struct inode *inode = mapping->host;
|
|
|
|
err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
|
|
if (err) {
|
|
put_page(page);
|
|
if (err == -EEXIST)
|
|
goto retry;
|
|
goto out;
|
|
}
|
|
|
|
spin_lock(&inode->i_lock);
|
|
inode->i_blocks += blocks_per_huge_page(h);
|
|
spin_unlock(&inode->i_lock);
|
|
} else {
|
|
lock_page(page);
|
|
if (unlikely(anon_vma_prepare(vma))) {
|
|
ret = VM_FAULT_OOM;
|
|
goto backout_unlocked;
|
|
}
|
|
anon_rmap = 1;
|
|
}
|
|
} else {
|
|
/*
|
|
* If memory error occurs between mmap() and fault, some process
|
|
* don't have hwpoisoned swap entry for errored virtual address.
|
|
* So we need to block hugepage fault by PG_hwpoison bit check.
|
|
*/
|
|
if (unlikely(PageHWPoison(page))) {
|
|
ret = VM_FAULT_HWPOISON |
|
|
VM_FAULT_SET_HINDEX(h - hstates);
|
|
goto backout_unlocked;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* If we are going to COW a private mapping later, we examine the
|
|
* pending reservations for this page now. This will ensure that
|
|
* any allocations necessary to record that reservation occur outside
|
|
* the spinlock.
|
|
*/
|
|
if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED))
|
|
if (vma_needs_reservation(h, vma, address) < 0) {
|
|
ret = VM_FAULT_OOM;
|
|
goto backout_unlocked;
|
|
}
|
|
|
|
spin_lock(&mm->page_table_lock);
|
|
size = i_size_read(mapping->host) >> huge_page_shift(h);
|
|
if (idx >= size)
|
|
goto backout;
|
|
|
|
ret = 0;
|
|
if (!huge_pte_none(huge_ptep_get(ptep)))
|
|
goto backout;
|
|
|
|
if (anon_rmap)
|
|
hugepage_add_new_anon_rmap(page, vma, address);
|
|
else
|
|
page_dup_rmap(page);
|
|
new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
|
|
&& (vma->vm_flags & VM_SHARED)));
|
|
set_huge_pte_at(mm, address, ptep, new_pte);
|
|
|
|
if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
|
|
/* Optimization, do the COW without a second fault */
|
|
ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page);
|
|
}
|
|
|
|
spin_unlock(&mm->page_table_lock);
|
|
unlock_page(page);
|
|
out:
|
|
return ret;
|
|
|
|
backout:
|
|
spin_unlock(&mm->page_table_lock);
|
|
backout_unlocked:
|
|
unlock_page(page);
|
|
put_page(page);
|
|
goto out;
|
|
}
|
|
|
|
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
unsigned long address, unsigned int flags)
|
|
{
|
|
pte_t *ptep;
|
|
pte_t entry;
|
|
int ret;
|
|
struct page *page = NULL;
|
|
struct page *pagecache_page = NULL;
|
|
static DEFINE_MUTEX(hugetlb_instantiation_mutex);
|
|
struct hstate *h = hstate_vma(vma);
|
|
|
|
address &= huge_page_mask(h);
|
|
|
|
ptep = huge_pte_offset(mm, address);
|
|
if (ptep) {
|
|
entry = huge_ptep_get(ptep);
|
|
if (unlikely(is_hugetlb_entry_migration(entry))) {
|
|
migration_entry_wait(mm, (pmd_t *)ptep, address);
|
|
return 0;
|
|
} else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
|
|
return VM_FAULT_HWPOISON_LARGE |
|
|
VM_FAULT_SET_HINDEX(h - hstates);
|
|
}
|
|
|
|
ptep = huge_pte_alloc(mm, address, huge_page_size(h));
|
|
if (!ptep)
|
|
return VM_FAULT_OOM;
|
|
|
|
/*
|
|
* Serialize hugepage allocation and instantiation, so that we don't
|
|
* get spurious allocation failures if two CPUs race to instantiate
|
|
* the same page in the page cache.
|
|
*/
|
|
mutex_lock(&hugetlb_instantiation_mutex);
|
|
entry = huge_ptep_get(ptep);
|
|
if (huge_pte_none(entry)) {
|
|
ret = hugetlb_no_page(mm, vma, address, ptep, flags);
|
|
goto out_mutex;
|
|
}
|
|
|
|
ret = 0;
|
|
|
|
/*
|
|
* If we are going to COW the mapping later, we examine the pending
|
|
* reservations for this page now. This will ensure that any
|
|
* allocations necessary to record that reservation occur outside the
|
|
* spinlock. For private mappings, we also lookup the pagecache
|
|
* page now as it is used to determine if a reservation has been
|
|
* consumed.
|
|
*/
|
|
if ((flags & FAULT_FLAG_WRITE) && !pte_write(entry)) {
|
|
if (vma_needs_reservation(h, vma, address) < 0) {
|
|
ret = VM_FAULT_OOM;
|
|
goto out_mutex;
|
|
}
|
|
|
|
if (!(vma->vm_flags & VM_MAYSHARE))
|
|
pagecache_page = hugetlbfs_pagecache_page(h,
|
|
vma, address);
|
|
}
|
|
|
|
/*
|
|
* hugetlb_cow() requires page locks of pte_page(entry) and
|
|
* pagecache_page, so here we need take the former one
|
|
* when page != pagecache_page or !pagecache_page.
|
|
* Note that locking order is always pagecache_page -> page,
|
|
* so no worry about deadlock.
|
|
*/
|
|
page = pte_page(entry);
|
|
if (page != pagecache_page)
|
|
lock_page(page);
|
|
|
|
spin_lock(&mm->page_table_lock);
|
|
/* Check for a racing update before calling hugetlb_cow */
|
|
if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
|
|
goto out_page_table_lock;
|
|
|
|
|
|
if (flags & FAULT_FLAG_WRITE) {
|
|
if (!pte_write(entry)) {
|
|
ret = hugetlb_cow(mm, vma, address, ptep, entry,
|
|
pagecache_page);
|
|
goto out_page_table_lock;
|
|
}
|
|
entry = pte_mkdirty(entry);
|
|
}
|
|
entry = pte_mkyoung(entry);
|
|
if (huge_ptep_set_access_flags(vma, address, ptep, entry,
|
|
flags & FAULT_FLAG_WRITE))
|
|
update_mmu_cache(vma, address, ptep);
|
|
|
|
out_page_table_lock:
|
|
spin_unlock(&mm->page_table_lock);
|
|
|
|
if (pagecache_page) {
|
|
unlock_page(pagecache_page);
|
|
put_page(pagecache_page);
|
|
}
|
|
if (page != pagecache_page)
|
|
unlock_page(page);
|
|
|
|
out_mutex:
|
|
mutex_unlock(&hugetlb_instantiation_mutex);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* Can be overriden by architectures */
|
|
__attribute__((weak)) struct page *
|
|
follow_huge_pud(struct mm_struct *mm, unsigned long address,
|
|
pud_t *pud, int write)
|
|
{
|
|
BUG();
|
|
return NULL;
|
|
}
|
|
|
|
int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
|
|
struct page **pages, struct vm_area_struct **vmas,
|
|
unsigned long *position, int *length, int i,
|
|
unsigned int flags)
|
|
{
|
|
unsigned long pfn_offset;
|
|
unsigned long vaddr = *position;
|
|
int remainder = *length;
|
|
struct hstate *h = hstate_vma(vma);
|
|
|
|
spin_lock(&mm->page_table_lock);
|
|
while (vaddr < vma->vm_end && remainder) {
|
|
pte_t *pte;
|
|
int absent;
|
|
struct page *page;
|
|
|
|
/*
|
|
* Some archs (sparc64, sh*) have multiple pte_ts to
|
|
* each hugepage. We have to make sure we get the
|
|
* first, for the page indexing below to work.
|
|
*/
|
|
pte = huge_pte_offset(mm, vaddr & huge_page_mask(h));
|
|
absent = !pte || huge_pte_none(huge_ptep_get(pte));
|
|
|
|
/*
|
|
* When coredumping, it suits get_dump_page if we just return
|
|
* an error where there's an empty slot with no huge pagecache
|
|
* to back it. This way, we avoid allocating a hugepage, and
|
|
* the sparse dumpfile avoids allocating disk blocks, but its
|
|
* huge holes still show up with zeroes where they need to be.
|
|
*/
|
|
if (absent && (flags & FOLL_DUMP) &&
|
|
!hugetlbfs_pagecache_present(h, vma, vaddr)) {
|
|
remainder = 0;
|
|
break;
|
|
}
|
|
|
|
if (absent ||
|
|
((flags & FOLL_WRITE) && !pte_write(huge_ptep_get(pte)))) {
|
|
int ret;
|
|
|
|
spin_unlock(&mm->page_table_lock);
|
|
ret = hugetlb_fault(mm, vma, vaddr,
|
|
(flags & FOLL_WRITE) ? FAULT_FLAG_WRITE : 0);
|
|
spin_lock(&mm->page_table_lock);
|
|
if (!(ret & VM_FAULT_ERROR))
|
|
continue;
|
|
|
|
remainder = 0;
|
|
break;
|
|
}
|
|
|
|
pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
|
|
page = pte_page(huge_ptep_get(pte));
|
|
same_page:
|
|
if (pages) {
|
|
pages[i] = mem_map_offset(page, pfn_offset);
|
|
get_page(pages[i]);
|
|
}
|
|
|
|
if (vmas)
|
|
vmas[i] = vma;
|
|
|
|
vaddr += PAGE_SIZE;
|
|
++pfn_offset;
|
|
--remainder;
|
|
++i;
|
|
if (vaddr < vma->vm_end && remainder &&
|
|
pfn_offset < pages_per_huge_page(h)) {
|
|
/*
|
|
* We use pfn_offset to avoid touching the pageframes
|
|
* of this compound page.
|
|
*/
|
|
goto same_page;
|
|
}
|
|
}
|
|
spin_unlock(&mm->page_table_lock);
|
|
*length = remainder;
|
|
*position = vaddr;
|
|
|
|
return i ? i : -EFAULT;
|
|
}
|
|
|
|
void hugetlb_change_protection(struct vm_area_struct *vma,
|
|
unsigned long address, unsigned long end, pgprot_t newprot)
|
|
{
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
unsigned long start = address;
|
|
pte_t *ptep;
|
|
pte_t pte;
|
|
struct hstate *h = hstate_vma(vma);
|
|
|
|
BUG_ON(address >= end);
|
|
flush_cache_range(vma, address, end);
|
|
|
|
mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
|
|
spin_lock(&mm->page_table_lock);
|
|
for (; address < end; address += huge_page_size(h)) {
|
|
ptep = huge_pte_offset(mm, address);
|
|
if (!ptep)
|
|
continue;
|
|
if (huge_pmd_unshare(mm, &address, ptep))
|
|
continue;
|
|
if (!huge_pte_none(huge_ptep_get(ptep))) {
|
|
pte = huge_ptep_get_and_clear(mm, address, ptep);
|
|
pte = pte_mkhuge(pte_modify(pte, newprot));
|
|
set_huge_pte_at(mm, address, ptep, pte);
|
|
}
|
|
}
|
|
spin_unlock(&mm->page_table_lock);
|
|
mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
|
|
|
|
flush_tlb_range(vma, start, end);
|
|
}
|
|
|
|
int hugetlb_reserve_pages(struct inode *inode,
|
|
long from, long to,
|
|
struct vm_area_struct *vma,
|
|
vm_flags_t vm_flags)
|
|
{
|
|
long ret, chg;
|
|
struct hstate *h = hstate_inode(inode);
|
|
|
|
/*
|
|
* Only apply hugepage reservation if asked. At fault time, an
|
|
* attempt will be made for VM_NORESERVE to allocate a page
|
|
* and filesystem quota without using reserves
|
|
*/
|
|
if (vm_flags & VM_NORESERVE)
|
|
return 0;
|
|
|
|
/*
|
|
* Shared mappings base their reservation on the number of pages that
|
|
* are already allocated on behalf of the file. Private mappings need
|
|
* to reserve the full area even if read-only as mprotect() may be
|
|
* called to make the mapping read-write. Assume !vma is a shm mapping
|
|
*/
|
|
if (!vma || vma->vm_flags & VM_MAYSHARE)
|
|
chg = region_chg(&inode->i_mapping->private_list, from, to);
|
|
else {
|
|
struct resv_map *resv_map = resv_map_alloc();
|
|
if (!resv_map)
|
|
return -ENOMEM;
|
|
|
|
chg = to - from;
|
|
|
|
set_vma_resv_map(vma, resv_map);
|
|
set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
|
|
}
|
|
|
|
if (chg < 0)
|
|
return chg;
|
|
|
|
/* There must be enough filesystem quota for the mapping */
|
|
if (hugetlb_get_quota(inode->i_mapping, chg))
|
|
return -ENOSPC;
|
|
|
|
/*
|
|
* Check enough hugepages are available for the reservation.
|
|
* Hand back the quota if there are not
|
|
*/
|
|
ret = hugetlb_acct_memory(h, chg);
|
|
if (ret < 0) {
|
|
hugetlb_put_quota(inode->i_mapping, chg);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Account for the reservations made. Shared mappings record regions
|
|
* that have reservations as they are shared by multiple VMAs.
|
|
* When the last VMA disappears, the region map says how much
|
|
* the reservation was and the page cache tells how much of
|
|
* the reservation was consumed. Private mappings are per-VMA and
|
|
* only the consumed reservations are tracked. When the VMA
|
|
* disappears, the original reservation is the VMA size and the
|
|
* consumed reservations are stored in the map. Hence, nothing
|
|
* else has to be done for private mappings here
|
|
*/
|
|
if (!vma || vma->vm_flags & VM_MAYSHARE)
|
|
region_add(&inode->i_mapping->private_list, from, to);
|
|
return 0;
|
|
}
|
|
|
|
void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
|
|
{
|
|
struct hstate *h = hstate_inode(inode);
|
|
long chg = region_truncate(&inode->i_mapping->private_list, offset);
|
|
|
|
spin_lock(&inode->i_lock);
|
|
inode->i_blocks -= (blocks_per_huge_page(h) * freed);
|
|
spin_unlock(&inode->i_lock);
|
|
|
|
hugetlb_put_quota(inode->i_mapping, (chg - freed));
|
|
hugetlb_acct_memory(h, -(chg - freed));
|
|
}
|
|
|
|
#ifdef CONFIG_MEMORY_FAILURE
|
|
|
|
/* Should be called in hugetlb_lock */
|
|
static int is_hugepage_on_freelist(struct page *hpage)
|
|
{
|
|
struct page *page;
|
|
struct page *tmp;
|
|
struct hstate *h = page_hstate(hpage);
|
|
int nid = page_to_nid(hpage);
|
|
|
|
list_for_each_entry_safe(page, tmp, &h->hugepage_freelists[nid], lru)
|
|
if (page == hpage)
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* This function is called from memory failure code.
|
|
* Assume the caller holds page lock of the head page.
|
|
*/
|
|
int dequeue_hwpoisoned_huge_page(struct page *hpage)
|
|
{
|
|
struct hstate *h = page_hstate(hpage);
|
|
int nid = page_to_nid(hpage);
|
|
int ret = -EBUSY;
|
|
|
|
spin_lock(&hugetlb_lock);
|
|
if (is_hugepage_on_freelist(hpage)) {
|
|
list_del(&hpage->lru);
|
|
set_page_refcounted(hpage);
|
|
h->free_huge_pages--;
|
|
h->free_huge_pages_node[nid]--;
|
|
ret = 0;
|
|
}
|
|
spin_unlock(&hugetlb_lock);
|
|
return ret;
|
|
}
|
|
#endif
|