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![Catalin Marinas](/assets/img/avatar_default.png)
The pointer to the page_cgroup table allocated in init_section_page_cgroup() is stored in section->page_cgroup as (base - pfn). Since this value does not point to the beginning or inside the allocated memory block, kmemleak reports a false positive. This was reported in bugzilla.kernel.org as #16297. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Adrien Dessemond <adrien.dessemond@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Andrew Morton <akpm@linux-foundation.org>
504 lines
11 KiB
C
504 lines
11 KiB
C
#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/bootmem.h>
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#include <linux/bit_spinlock.h>
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#include <linux/page_cgroup.h>
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#include <linux/hash.h>
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#include <linux/slab.h>
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#include <linux/memory.h>
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#include <linux/vmalloc.h>
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#include <linux/cgroup.h>
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#include <linux/swapops.h>
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#include <linux/kmemleak.h>
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static void __meminit
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__init_page_cgroup(struct page_cgroup *pc, unsigned long pfn)
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{
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pc->flags = 0;
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pc->mem_cgroup = NULL;
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pc->page = pfn_to_page(pfn);
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INIT_LIST_HEAD(&pc->lru);
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}
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static unsigned long total_usage;
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#if !defined(CONFIG_SPARSEMEM)
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void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
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{
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pgdat->node_page_cgroup = NULL;
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}
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struct page_cgroup *lookup_page_cgroup(struct page *page)
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{
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unsigned long pfn = page_to_pfn(page);
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unsigned long offset;
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struct page_cgroup *base;
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base = NODE_DATA(page_to_nid(page))->node_page_cgroup;
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if (unlikely(!base))
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return NULL;
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offset = pfn - NODE_DATA(page_to_nid(page))->node_start_pfn;
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return base + offset;
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}
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static int __init alloc_node_page_cgroup(int nid)
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{
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struct page_cgroup *base, *pc;
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unsigned long table_size;
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unsigned long start_pfn, nr_pages, index;
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start_pfn = NODE_DATA(nid)->node_start_pfn;
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nr_pages = NODE_DATA(nid)->node_spanned_pages;
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if (!nr_pages)
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return 0;
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table_size = sizeof(struct page_cgroup) * nr_pages;
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base = __alloc_bootmem_node_nopanic(NODE_DATA(nid),
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table_size, PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
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if (!base)
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return -ENOMEM;
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for (index = 0; index < nr_pages; index++) {
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pc = base + index;
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__init_page_cgroup(pc, start_pfn + index);
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}
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NODE_DATA(nid)->node_page_cgroup = base;
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total_usage += table_size;
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return 0;
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}
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void __init page_cgroup_init_flatmem(void)
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{
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int nid, fail;
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if (mem_cgroup_disabled())
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return;
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for_each_online_node(nid) {
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fail = alloc_node_page_cgroup(nid);
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if (fail)
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goto fail;
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}
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printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
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printk(KERN_INFO "please try 'cgroup_disable=memory' option if you"
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" don't want memory cgroups\n");
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return;
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fail:
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printk(KERN_CRIT "allocation of page_cgroup failed.\n");
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printk(KERN_CRIT "please try 'cgroup_disable=memory' boot option\n");
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panic("Out of memory");
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}
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#else /* CONFIG_FLAT_NODE_MEM_MAP */
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struct page_cgroup *lookup_page_cgroup(struct page *page)
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{
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unsigned long pfn = page_to_pfn(page);
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struct mem_section *section = __pfn_to_section(pfn);
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if (!section->page_cgroup)
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return NULL;
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return section->page_cgroup + pfn;
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}
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/* __alloc_bootmem...() is protected by !slab_available() */
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static int __init_refok init_section_page_cgroup(unsigned long pfn)
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{
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struct mem_section *section = __pfn_to_section(pfn);
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struct page_cgroup *base, *pc;
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unsigned long table_size;
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int nid, index;
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if (!section->page_cgroup) {
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nid = page_to_nid(pfn_to_page(pfn));
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table_size = sizeof(struct page_cgroup) * PAGES_PER_SECTION;
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VM_BUG_ON(!slab_is_available());
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if (node_state(nid, N_HIGH_MEMORY)) {
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base = kmalloc_node(table_size,
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GFP_KERNEL | __GFP_NOWARN, nid);
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if (!base)
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base = vmalloc_node(table_size, nid);
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} else {
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base = kmalloc(table_size, GFP_KERNEL | __GFP_NOWARN);
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if (!base)
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base = vmalloc(table_size);
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}
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/*
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* The value stored in section->page_cgroup is (base - pfn)
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* and it does not point to the memory block allocated above,
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* causing kmemleak false positives.
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*/
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kmemleak_not_leak(base);
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} else {
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/*
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* We don't have to allocate page_cgroup again, but
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* address of memmap may be changed. So, we have to initialize
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* again.
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*/
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base = section->page_cgroup + pfn;
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table_size = 0;
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/* check address of memmap is changed or not. */
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if (base->page == pfn_to_page(pfn))
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return 0;
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}
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if (!base) {
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printk(KERN_ERR "page cgroup allocation failure\n");
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return -ENOMEM;
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}
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for (index = 0; index < PAGES_PER_SECTION; index++) {
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pc = base + index;
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__init_page_cgroup(pc, pfn + index);
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}
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section->page_cgroup = base - pfn;
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total_usage += table_size;
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return 0;
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}
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#ifdef CONFIG_MEMORY_HOTPLUG
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void __free_page_cgroup(unsigned long pfn)
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{
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struct mem_section *ms;
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struct page_cgroup *base;
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ms = __pfn_to_section(pfn);
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if (!ms || !ms->page_cgroup)
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return;
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base = ms->page_cgroup + pfn;
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if (is_vmalloc_addr(base)) {
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vfree(base);
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ms->page_cgroup = NULL;
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} else {
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struct page *page = virt_to_page(base);
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if (!PageReserved(page)) { /* Is bootmem ? */
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kfree(base);
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ms->page_cgroup = NULL;
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}
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}
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}
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int __meminit online_page_cgroup(unsigned long start_pfn,
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unsigned long nr_pages,
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int nid)
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{
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unsigned long start, end, pfn;
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int fail = 0;
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start = start_pfn & ~(PAGES_PER_SECTION - 1);
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end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);
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for (pfn = start; !fail && pfn < end; pfn += PAGES_PER_SECTION) {
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if (!pfn_present(pfn))
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continue;
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fail = init_section_page_cgroup(pfn);
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}
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if (!fail)
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return 0;
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/* rollback */
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for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
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__free_page_cgroup(pfn);
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return -ENOMEM;
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}
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int __meminit offline_page_cgroup(unsigned long start_pfn,
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unsigned long nr_pages, int nid)
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{
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unsigned long start, end, pfn;
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start = start_pfn & ~(PAGES_PER_SECTION - 1);
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end = ALIGN(start_pfn + nr_pages, PAGES_PER_SECTION);
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for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION)
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__free_page_cgroup(pfn);
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return 0;
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}
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static int __meminit page_cgroup_callback(struct notifier_block *self,
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unsigned long action, void *arg)
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{
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struct memory_notify *mn = arg;
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int ret = 0;
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switch (action) {
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case MEM_GOING_ONLINE:
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ret = online_page_cgroup(mn->start_pfn,
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mn->nr_pages, mn->status_change_nid);
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break;
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case MEM_OFFLINE:
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offline_page_cgroup(mn->start_pfn,
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mn->nr_pages, mn->status_change_nid);
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break;
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case MEM_CANCEL_ONLINE:
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case MEM_GOING_OFFLINE:
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break;
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case MEM_ONLINE:
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case MEM_CANCEL_OFFLINE:
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break;
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}
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if (ret)
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ret = notifier_from_errno(ret);
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else
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ret = NOTIFY_OK;
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return ret;
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}
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#endif
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void __init page_cgroup_init(void)
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{
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unsigned long pfn;
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int fail = 0;
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if (mem_cgroup_disabled())
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return;
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for (pfn = 0; !fail && pfn < max_pfn; pfn += PAGES_PER_SECTION) {
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if (!pfn_present(pfn))
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continue;
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fail = init_section_page_cgroup(pfn);
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}
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if (fail) {
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printk(KERN_CRIT "try 'cgroup_disable=memory' boot option\n");
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panic("Out of memory");
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} else {
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hotplug_memory_notifier(page_cgroup_callback, 0);
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}
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printk(KERN_INFO "allocated %ld bytes of page_cgroup\n", total_usage);
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printk(KERN_INFO "please try 'cgroup_disable=memory' option if you don't"
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" want memory cgroups\n");
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}
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void __meminit pgdat_page_cgroup_init(struct pglist_data *pgdat)
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{
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return;
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}
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#endif
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#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
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static DEFINE_MUTEX(swap_cgroup_mutex);
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struct swap_cgroup_ctrl {
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struct page **map;
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unsigned long length;
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spinlock_t lock;
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};
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struct swap_cgroup_ctrl swap_cgroup_ctrl[MAX_SWAPFILES];
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struct swap_cgroup {
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unsigned short id;
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};
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#define SC_PER_PAGE (PAGE_SIZE/sizeof(struct swap_cgroup))
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#define SC_POS_MASK (SC_PER_PAGE - 1)
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/*
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* SwapCgroup implements "lookup" and "exchange" operations.
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* In typical usage, this swap_cgroup is accessed via memcg's charge/uncharge
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* against SwapCache. At swap_free(), this is accessed directly from swap.
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*
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* This means,
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* - we have no race in "exchange" when we're accessed via SwapCache because
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* SwapCache(and its swp_entry) is under lock.
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* - When called via swap_free(), there is no user of this entry and no race.
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* Then, we don't need lock around "exchange".
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*
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* TODO: we can push these buffers out to HIGHMEM.
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*/
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/*
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* allocate buffer for swap_cgroup.
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*/
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static int swap_cgroup_prepare(int type)
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{
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struct page *page;
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struct swap_cgroup_ctrl *ctrl;
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unsigned long idx, max;
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ctrl = &swap_cgroup_ctrl[type];
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for (idx = 0; idx < ctrl->length; idx++) {
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page = alloc_page(GFP_KERNEL | __GFP_ZERO);
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if (!page)
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goto not_enough_page;
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ctrl->map[idx] = page;
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}
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return 0;
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not_enough_page:
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max = idx;
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for (idx = 0; idx < max; idx++)
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__free_page(ctrl->map[idx]);
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return -ENOMEM;
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}
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/**
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* swap_cgroup_cmpxchg - cmpxchg mem_cgroup's id for this swp_entry.
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* @end: swap entry to be cmpxchged
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* @old: old id
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* @new: new id
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*
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* Returns old id at success, 0 at failure.
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* (There is no mem_cgroup useing 0 as its id)
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*/
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unsigned short swap_cgroup_cmpxchg(swp_entry_t ent,
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unsigned short old, unsigned short new)
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{
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int type = swp_type(ent);
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unsigned long offset = swp_offset(ent);
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unsigned long idx = offset / SC_PER_PAGE;
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unsigned long pos = offset & SC_POS_MASK;
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struct swap_cgroup_ctrl *ctrl;
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struct page *mappage;
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struct swap_cgroup *sc;
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unsigned long flags;
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unsigned short retval;
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ctrl = &swap_cgroup_ctrl[type];
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mappage = ctrl->map[idx];
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sc = page_address(mappage);
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sc += pos;
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spin_lock_irqsave(&ctrl->lock, flags);
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retval = sc->id;
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if (retval == old)
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sc->id = new;
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else
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retval = 0;
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spin_unlock_irqrestore(&ctrl->lock, flags);
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return retval;
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}
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/**
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* swap_cgroup_record - record mem_cgroup for this swp_entry.
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* @ent: swap entry to be recorded into
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* @mem: mem_cgroup to be recorded
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*
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* Returns old value at success, 0 at failure.
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* (Of course, old value can be 0.)
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*/
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unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id)
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{
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int type = swp_type(ent);
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unsigned long offset = swp_offset(ent);
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unsigned long idx = offset / SC_PER_PAGE;
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unsigned long pos = offset & SC_POS_MASK;
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struct swap_cgroup_ctrl *ctrl;
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struct page *mappage;
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struct swap_cgroup *sc;
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unsigned short old;
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unsigned long flags;
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ctrl = &swap_cgroup_ctrl[type];
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mappage = ctrl->map[idx];
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sc = page_address(mappage);
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sc += pos;
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spin_lock_irqsave(&ctrl->lock, flags);
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old = sc->id;
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sc->id = id;
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spin_unlock_irqrestore(&ctrl->lock, flags);
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return old;
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}
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/**
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* lookup_swap_cgroup - lookup mem_cgroup tied to swap entry
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* @ent: swap entry to be looked up.
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*
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* Returns CSS ID of mem_cgroup at success. 0 at failure. (0 is invalid ID)
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*/
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unsigned short lookup_swap_cgroup(swp_entry_t ent)
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{
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int type = swp_type(ent);
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unsigned long offset = swp_offset(ent);
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unsigned long idx = offset / SC_PER_PAGE;
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unsigned long pos = offset & SC_POS_MASK;
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struct swap_cgroup_ctrl *ctrl;
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struct page *mappage;
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struct swap_cgroup *sc;
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unsigned short ret;
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ctrl = &swap_cgroup_ctrl[type];
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mappage = ctrl->map[idx];
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sc = page_address(mappage);
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sc += pos;
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ret = sc->id;
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return ret;
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}
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int swap_cgroup_swapon(int type, unsigned long max_pages)
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{
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void *array;
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unsigned long array_size;
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unsigned long length;
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struct swap_cgroup_ctrl *ctrl;
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if (!do_swap_account)
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return 0;
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length = ((max_pages/SC_PER_PAGE) + 1);
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array_size = length * sizeof(void *);
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array = vmalloc(array_size);
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if (!array)
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goto nomem;
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memset(array, 0, array_size);
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ctrl = &swap_cgroup_ctrl[type];
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mutex_lock(&swap_cgroup_mutex);
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ctrl->length = length;
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ctrl->map = array;
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spin_lock_init(&ctrl->lock);
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if (swap_cgroup_prepare(type)) {
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/* memory shortage */
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ctrl->map = NULL;
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ctrl->length = 0;
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vfree(array);
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mutex_unlock(&swap_cgroup_mutex);
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goto nomem;
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}
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mutex_unlock(&swap_cgroup_mutex);
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return 0;
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nomem:
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printk(KERN_INFO "couldn't allocate enough memory for swap_cgroup.\n");
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printk(KERN_INFO
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"swap_cgroup can be disabled by noswapaccount boot option\n");
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return -ENOMEM;
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}
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void swap_cgroup_swapoff(int type)
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{
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int i;
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struct swap_cgroup_ctrl *ctrl;
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if (!do_swap_account)
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return;
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mutex_lock(&swap_cgroup_mutex);
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ctrl = &swap_cgroup_ctrl[type];
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if (ctrl->map) {
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for (i = 0; i < ctrl->length; i++) {
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struct page *page = ctrl->map[i];
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if (page)
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__free_page(page);
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}
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vfree(ctrl->map);
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ctrl->map = NULL;
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ctrl->length = 0;
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}
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mutex_unlock(&swap_cgroup_mutex);
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}
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#endif
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