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memcg: bad page if page_cgroup when free

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Replace free_hot_cold_page's VM_BUG_ON(page_get_page_cgroup(page)) by a "Bad
page state" and clear: most users don't have CONFIG_DEBUG_VM on, and if it
were set here, it'd likely cause corruption when the page is reused.

Don't use page_assign_page_cgroup to clear it: that should be private to
memcontrol.c, and always called with the lock taken; and memmap_init_zone
doesn't need it either - like page->mapping and other pointers throughout the
kernel, Linux assumes pointers in zeroed structures are NULL pointers.

Instead use page_reset_bad_cgroup, added to memcontrol.h for this only.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: David Rientjes <rientjes@google.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hugh Dickins
2008-03-04 14:29:07 -08:00
committed by Linus Torvalds
parent 98837c7f82
commit 9442ec9df4
3 changed files with 28 additions and 25 deletions
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18
mm/page_alloc.c
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@ -222,13 +222,19 @@ static inline int bad_range(struct zone *zone, struct page *page)
static void bad_page(struct page *page)
{
printk(KERN_EMERG "Bad page state in process '%s'\n"
KERN_EMERG "page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n"
KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
KERN_EMERG "Backtrace:\n",
void *pc = page_get_page_cgroup(page);
printk(KERN_EMERG "Bad page state in process '%s'\n" KERN_EMERG
"page:%p flags:0x%0*lx mapping:%p mapcount:%d count:%d\n",
current->comm, page, (int)(2*sizeof(unsigned long)),
(unsigned long)page->flags, page->mapping,
page_mapcount(page), page_count(page));
if (pc) {
printk(KERN_EMERG "cgroup:%p\n", pc);
page_reset_bad_cgroup(page);
}
printk(KERN_EMERG "Trying to fix it up, but a reboot is needed\n"
KERN_EMERG "Backtrace:\n");
dump_stack();
page->flags &= ~(1 << PG_lru |
1 << PG_private |
@ -454,6 +460,7 @@ static inline int free_pages_check(struct page *page)
{
if (unlikely(page_mapcount(page) |
(page->mapping != NULL) |
(page_get_page_cgroup(page) != NULL) |
(page_count(page) != 0) |
(page->flags & (
1 << PG_lru |
@ -603,6 +610,7 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
{
if (unlikely(page_mapcount(page) |
(page->mapping != NULL) |
(page_get_page_cgroup(page) != NULL) |
(page_count(page) != 0) |
(page->flags & (
1 << PG_lru |
@ -989,7 +997,6 @@ static void free_hot_cold_page(struct page *page, int cold)
if (!PageHighMem(page))
debug_check_no_locks_freed(page_address(page), PAGE_SIZE);
VM_BUG_ON(page_get_page_cgroup(page));
arch_free_page(page, 0);
kernel_map_pages(page, 1, 0);
@ -2528,7 +2535,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
set_page_links(page, zone, nid, pfn);
init_page_count(page);
reset_page_mapcount(page);
page_assign_page_cgroup(page, NULL);
SetPageReserved(page);
/*