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![Aneesh Kumar K.V](/assets/img/avatar_default.png)
Architectures like powerpc will like to use different page table allocators and mapping mechanisms to implement vmemmap optimization. Similar to vmemmap_populate allow architectures to implement vmemap_populate_compound_pages Link: https://lkml.kernel.org/r/20230724190759.483013-5-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Joao Martins <joao.m.martins@oracle.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
473 lines
12 KiB
C
473 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Virtual Memory Map support
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*
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* (C) 2007 sgi. Christoph Lameter.
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*
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* Virtual memory maps allow VM primitives pfn_to_page, page_to_pfn,
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* virt_to_page, page_address() to be implemented as a base offset
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* calculation without memory access.
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*
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* However, virtual mappings need a page table and TLBs. Many Linux
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* architectures already map their physical space using 1-1 mappings
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* via TLBs. For those arches the virtual memory map is essentially
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* for free if we use the same page size as the 1-1 mappings. In that
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* case the overhead consists of a few additional pages that are
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* allocated to create a view of memory for vmemmap.
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*
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* The architecture is expected to provide a vmemmap_populate() function
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* to instantiate the mapping.
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*/
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/memblock.h>
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#include <linux/memremap.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/vmalloc.h>
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#include <linux/sched.h>
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#include <asm/dma.h>
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#include <asm/pgalloc.h>
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/*
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* Allocate a block of memory to be used to back the virtual memory map
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* or to back the page tables that are used to create the mapping.
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* Uses the main allocators if they are available, else bootmem.
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*/
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static void * __ref __earlyonly_bootmem_alloc(int node,
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unsigned long size,
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unsigned long align,
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unsigned long goal)
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{
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return memblock_alloc_try_nid_raw(size, align, goal,
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MEMBLOCK_ALLOC_ACCESSIBLE, node);
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}
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void * __meminit vmemmap_alloc_block(unsigned long size, int node)
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{
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/* If the main allocator is up use that, fallback to bootmem. */
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if (slab_is_available()) {
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gfp_t gfp_mask = GFP_KERNEL|__GFP_RETRY_MAYFAIL|__GFP_NOWARN;
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int order = get_order(size);
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static bool warned;
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struct page *page;
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page = alloc_pages_node(node, gfp_mask, order);
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if (page)
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return page_address(page);
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if (!warned) {
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warn_alloc(gfp_mask & ~__GFP_NOWARN, NULL,
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"vmemmap alloc failure: order:%u", order);
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warned = true;
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}
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return NULL;
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} else
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return __earlyonly_bootmem_alloc(node, size, size,
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__pa(MAX_DMA_ADDRESS));
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}
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static void * __meminit altmap_alloc_block_buf(unsigned long size,
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struct vmem_altmap *altmap);
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/* need to make sure size is all the same during early stage */
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void * __meminit vmemmap_alloc_block_buf(unsigned long size, int node,
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struct vmem_altmap *altmap)
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{
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void *ptr;
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if (altmap)
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return altmap_alloc_block_buf(size, altmap);
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ptr = sparse_buffer_alloc(size);
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if (!ptr)
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ptr = vmemmap_alloc_block(size, node);
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return ptr;
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}
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static unsigned long __meminit vmem_altmap_next_pfn(struct vmem_altmap *altmap)
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{
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return altmap->base_pfn + altmap->reserve + altmap->alloc
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+ altmap->align;
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}
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static unsigned long __meminit vmem_altmap_nr_free(struct vmem_altmap *altmap)
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{
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unsigned long allocated = altmap->alloc + altmap->align;
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if (altmap->free > allocated)
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return altmap->free - allocated;
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return 0;
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}
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static void * __meminit altmap_alloc_block_buf(unsigned long size,
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struct vmem_altmap *altmap)
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{
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unsigned long pfn, nr_pfns, nr_align;
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if (size & ~PAGE_MASK) {
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pr_warn_once("%s: allocations must be multiple of PAGE_SIZE (%ld)\n",
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__func__, size);
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return NULL;
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}
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pfn = vmem_altmap_next_pfn(altmap);
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nr_pfns = size >> PAGE_SHIFT;
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nr_align = 1UL << find_first_bit(&nr_pfns, BITS_PER_LONG);
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nr_align = ALIGN(pfn, nr_align) - pfn;
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if (nr_pfns + nr_align > vmem_altmap_nr_free(altmap))
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return NULL;
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altmap->alloc += nr_pfns;
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altmap->align += nr_align;
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pfn += nr_align;
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pr_debug("%s: pfn: %#lx alloc: %ld align: %ld nr: %#lx\n",
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__func__, pfn, altmap->alloc, altmap->align, nr_pfns);
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return __va(__pfn_to_phys(pfn));
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}
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void __meminit vmemmap_verify(pte_t *pte, int node,
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unsigned long start, unsigned long end)
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{
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unsigned long pfn = pte_pfn(ptep_get(pte));
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int actual_node = early_pfn_to_nid(pfn);
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if (node_distance(actual_node, node) > LOCAL_DISTANCE)
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pr_warn_once("[%lx-%lx] potential offnode page_structs\n",
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start, end - 1);
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}
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pte_t * __meminit vmemmap_pte_populate(pmd_t *pmd, unsigned long addr, int node,
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struct vmem_altmap *altmap,
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struct page *reuse)
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{
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pte_t *pte = pte_offset_kernel(pmd, addr);
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if (pte_none(ptep_get(pte))) {
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pte_t entry;
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void *p;
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if (!reuse) {
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p = vmemmap_alloc_block_buf(PAGE_SIZE, node, altmap);
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if (!p)
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return NULL;
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} else {
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/*
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* When a PTE/PMD entry is freed from the init_mm
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* there's a free_pages() call to this page allocated
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* above. Thus this get_page() is paired with the
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* put_page_testzero() on the freeing path.
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* This can only called by certain ZONE_DEVICE path,
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* and through vmemmap_populate_compound_pages() when
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* slab is available.
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*/
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get_page(reuse);
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p = page_to_virt(reuse);
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}
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entry = pfn_pte(__pa(p) >> PAGE_SHIFT, PAGE_KERNEL);
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set_pte_at(&init_mm, addr, pte, entry);
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}
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return pte;
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}
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static void * __meminit vmemmap_alloc_block_zero(unsigned long size, int node)
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{
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void *p = vmemmap_alloc_block(size, node);
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if (!p)
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return NULL;
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memset(p, 0, size);
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return p;
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}
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pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
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{
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pmd_t *pmd = pmd_offset(pud, addr);
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if (pmd_none(*pmd)) {
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void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
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if (!p)
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return NULL;
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pmd_populate_kernel(&init_mm, pmd, p);
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}
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return pmd;
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}
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void __weak __meminit pmd_init(void *addr)
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{
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}
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pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
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{
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pud_t *pud = pud_offset(p4d, addr);
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if (pud_none(*pud)) {
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void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
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if (!p)
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return NULL;
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pmd_init(p);
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pud_populate(&init_mm, pud, p);
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}
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return pud;
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}
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void __weak __meminit pud_init(void *addr)
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{
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}
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p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
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{
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p4d_t *p4d = p4d_offset(pgd, addr);
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if (p4d_none(*p4d)) {
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void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
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if (!p)
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return NULL;
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pud_init(p);
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p4d_populate(&init_mm, p4d, p);
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}
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return p4d;
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}
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pgd_t * __meminit vmemmap_pgd_populate(unsigned long addr, int node)
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{
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pgd_t *pgd = pgd_offset_k(addr);
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if (pgd_none(*pgd)) {
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void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
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if (!p)
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return NULL;
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pgd_populate(&init_mm, pgd, p);
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}
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return pgd;
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}
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static pte_t * __meminit vmemmap_populate_address(unsigned long addr, int node,
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struct vmem_altmap *altmap,
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struct page *reuse)
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{
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pgd_t *pgd;
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p4d_t *p4d;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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pgd = vmemmap_pgd_populate(addr, node);
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if (!pgd)
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return NULL;
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p4d = vmemmap_p4d_populate(pgd, addr, node);
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if (!p4d)
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return NULL;
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pud = vmemmap_pud_populate(p4d, addr, node);
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if (!pud)
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return NULL;
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pmd = vmemmap_pmd_populate(pud, addr, node);
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if (!pmd)
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return NULL;
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pte = vmemmap_pte_populate(pmd, addr, node, altmap, reuse);
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if (!pte)
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return NULL;
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vmemmap_verify(pte, node, addr, addr + PAGE_SIZE);
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return pte;
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}
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static int __meminit vmemmap_populate_range(unsigned long start,
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unsigned long end, int node,
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struct vmem_altmap *altmap,
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struct page *reuse)
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{
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unsigned long addr = start;
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pte_t *pte;
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for (; addr < end; addr += PAGE_SIZE) {
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pte = vmemmap_populate_address(addr, node, altmap, reuse);
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if (!pte)
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return -ENOMEM;
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}
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return 0;
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}
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int __meminit vmemmap_populate_basepages(unsigned long start, unsigned long end,
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int node, struct vmem_altmap *altmap)
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{
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return vmemmap_populate_range(start, end, node, altmap, NULL);
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}
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void __weak __meminit vmemmap_set_pmd(pmd_t *pmd, void *p, int node,
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unsigned long addr, unsigned long next)
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{
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}
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int __weak __meminit vmemmap_check_pmd(pmd_t *pmd, int node,
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unsigned long addr, unsigned long next)
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{
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return 0;
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}
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int __meminit vmemmap_populate_hugepages(unsigned long start, unsigned long end,
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int node, struct vmem_altmap *altmap)
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{
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unsigned long addr;
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unsigned long next;
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pgd_t *pgd;
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p4d_t *p4d;
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pud_t *pud;
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pmd_t *pmd;
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for (addr = start; addr < end; addr = next) {
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next = pmd_addr_end(addr, end);
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pgd = vmemmap_pgd_populate(addr, node);
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if (!pgd)
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return -ENOMEM;
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p4d = vmemmap_p4d_populate(pgd, addr, node);
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if (!p4d)
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return -ENOMEM;
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pud = vmemmap_pud_populate(p4d, addr, node);
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if (!pud)
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return -ENOMEM;
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pmd = pmd_offset(pud, addr);
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if (pmd_none(READ_ONCE(*pmd))) {
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void *p;
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p = vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);
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if (p) {
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vmemmap_set_pmd(pmd, p, node, addr, next);
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continue;
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} else if (altmap) {
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/*
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* No fallback: In any case we care about, the
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* altmap should be reasonably sized and aligned
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* such that vmemmap_alloc_block_buf() will always
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* succeed. For consistency with the PTE case,
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* return an error here as failure could indicate
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* a configuration issue with the size of the altmap.
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*/
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return -ENOMEM;
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}
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} else if (vmemmap_check_pmd(pmd, node, addr, next))
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continue;
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if (vmemmap_populate_basepages(addr, next, node, altmap))
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return -ENOMEM;
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}
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return 0;
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}
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#ifndef vmemmap_populate_compound_pages
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/*
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* For compound pages bigger than section size (e.g. x86 1G compound
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* pages with 2M subsection size) fill the rest of sections as tail
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* pages.
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*
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* Note that memremap_pages() resets @nr_range value and will increment
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* it after each range successful onlining. Thus the value or @nr_range
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* at section memmap populate corresponds to the in-progress range
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* being onlined here.
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*/
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static bool __meminit reuse_compound_section(unsigned long start_pfn,
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struct dev_pagemap *pgmap)
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{
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unsigned long nr_pages = pgmap_vmemmap_nr(pgmap);
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unsigned long offset = start_pfn -
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PHYS_PFN(pgmap->ranges[pgmap->nr_range].start);
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return !IS_ALIGNED(offset, nr_pages) && nr_pages > PAGES_PER_SUBSECTION;
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}
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static pte_t * __meminit compound_section_tail_page(unsigned long addr)
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{
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pte_t *pte;
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addr -= PAGE_SIZE;
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/*
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* Assuming sections are populated sequentially, the previous section's
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* page data can be reused.
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*/
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pte = pte_offset_kernel(pmd_off_k(addr), addr);
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if (!pte)
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return NULL;
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return pte;
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}
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static int __meminit vmemmap_populate_compound_pages(unsigned long start_pfn,
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unsigned long start,
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unsigned long end, int node,
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struct dev_pagemap *pgmap)
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{
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unsigned long size, addr;
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pte_t *pte;
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int rc;
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if (reuse_compound_section(start_pfn, pgmap)) {
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pte = compound_section_tail_page(start);
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if (!pte)
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return -ENOMEM;
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/*
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* Reuse the page that was populated in the prior iteration
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* with just tail struct pages.
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*/
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return vmemmap_populate_range(start, end, node, NULL,
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pte_page(ptep_get(pte)));
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}
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size = min(end - start, pgmap_vmemmap_nr(pgmap) * sizeof(struct page));
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for (addr = start; addr < end; addr += size) {
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unsigned long next, last = addr + size;
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/* Populate the head page vmemmap page */
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pte = vmemmap_populate_address(addr, node, NULL, NULL);
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if (!pte)
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return -ENOMEM;
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/* Populate the tail pages vmemmap page */
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next = addr + PAGE_SIZE;
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pte = vmemmap_populate_address(next, node, NULL, NULL);
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if (!pte)
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return -ENOMEM;
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/*
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* Reuse the previous page for the rest of tail pages
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* See layout diagram in Documentation/mm/vmemmap_dedup.rst
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*/
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next += PAGE_SIZE;
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rc = vmemmap_populate_range(next, last, node, NULL,
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pte_page(ptep_get(pte)));
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if (rc)
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return -ENOMEM;
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}
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return 0;
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}
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#endif
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struct page * __meminit __populate_section_memmap(unsigned long pfn,
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unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
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struct dev_pagemap *pgmap)
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{
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unsigned long start = (unsigned long) pfn_to_page(pfn);
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unsigned long end = start + nr_pages * sizeof(struct page);
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int r;
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if (WARN_ON_ONCE(!IS_ALIGNED(pfn, PAGES_PER_SUBSECTION) ||
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!IS_ALIGNED(nr_pages, PAGES_PER_SUBSECTION)))
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return NULL;
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if (vmemmap_can_optimize(altmap, pgmap))
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r = vmemmap_populate_compound_pages(pfn, start, end, nid, pgmap);
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else
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r = vmemmap_populate(start, end, nid, altmap);
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if (r < 0)
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return NULL;
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return pfn_to_page(pfn);
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}
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