Messages in this thread Patch in this message | | | Date | Tue, 5 Jan 2010 10:26:44 +0000 (GMT) | From | Hugh Dickins <> | Subject | Re: [00/97] 2.6.32.3 stable review |
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On Mon, 4 Jan 2010, Greg KH wrote: > This is the start of the stable review cycle for the 2.6.32.3 release. > There are 97 patches in this series, all will be posted as a response to > this one. If anyone has any issues with these being applied, please let > us know. If anyone is a maintainer of the proper subsystem, and wants > to add a Signed-off-by: line to the patch, please respond with it.
I had hoped that the patch below would make it into 2.6.32.3: but so long as it's not lost, I think it can wait until 2.6.32.4.
Thanks, Hugh
From hugh.dickins@tiscali.co.uk Wed Dec 30 23:00:31 2009 Date: Wed, 30 Dec 2009 23:00:30 +0000 (GMT) From: Hugh Dickins <hugh.dickins@tiscali.co.uk> To: stable@kernel.org Cc: Izik Eidus <ieidus@redhat.com>, Andrea Arcangeli <aarcange@redhat.com>, Chris Wright <chrisw@redhat.com>, Rik van Riel <riel@redhat.com>, Mel Gorman <mel@csn.ul.ie>, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>, Andrew Morton <akpm@linux-foundation.org> Subject: [PATCH 2.6.32-stable] ksm: fix mlockfreed to munlocked
2.6.33-rc1 commit 73848b4684e84a84cfd1555af78d41158f31e16b, adjusted to include 31e855ea7173bdb0520f9684580423a9560f66e0's movement of the unlock_page(oldpage), but omit other intervening cleanups.
When KSM merges an mlocked page, it has been forgetting to munlock it: that's been left to free_page_mlock(), which reports it in /proc/vmstat as unevictable_pgs_mlockfreed instead of unevictable_pgs_munlocked, which indicates that such pages _might_ be left unevictable for long after they should be evictable. Call munlock_vma_page() to fix that.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> ---
mm/internal.h | 3 ++- mm/ksm.c | 14 +++++++------- mm/mlock.c | 4 ++-- 3 files changed, 11 insertions(+), 10 deletions(-)
--- 2.6.32.2/mm/internal.h 2009-12-03 03:51:21.000000000 +0000 +++ stable/mm/internal.h 2009-12-30 20:38:17.000000000 +0000 @@ -107,9 +107,10 @@ static inline int is_mlocked_vma(struct } /* - * must be called with vma's mmap_sem held for read, and page locked. + * must be called with vma's mmap_sem held for read or write, and page locked. */ extern void mlock_vma_page(struct page *page); +extern void munlock_vma_page(struct page *page); /* * Clear the page's PageMlocked(). This can be useful in a situation where --- 2.6.32.2/mm/ksm.c 2009-12-03 03:51:21.000000000 +0000 +++ stable/mm/ksm.c 2009-12-30 20:38:17.000000000 +0000 @@ -34,6 +34,7 @@ #include <linux/ksm.h> #include <asm/tlbflush.h> +#include "internal.h" /* * A few notes about the KSM scanning process, @@ -767,15 +768,14 @@ static int try_to_merge_one_page(struct * ptes are necessarily already write-protected. But in either * case, we need to lock and check page_count is not raised. */ - if (write_protect_page(vma, oldpage, &orig_pte)) { - unlock_page(oldpage); - goto out_putpage; - } - unlock_page(oldpage); - - if (pages_identical(oldpage, newpage)) + if (write_protect_page(vma, oldpage, &orig_pte) == 0 && + pages_identical(oldpage, newpage)) err = replace_page(vma, oldpage, newpage, orig_pte); + if ((vma->vm_flags & VM_LOCKED) && !err) + munlock_vma_page(oldpage); + + unlock_page(oldpage); out_putpage: put_page(oldpage); put_page(newpage); --- 2.6.32.2/mm/mlock.c 2009-12-03 03:51:21.000000000 +0000 +++ stable/mm/mlock.c 2009-12-30 20:38:17.000000000 +0000 @@ -99,14 +99,14 @@ void mlock_vma_page(struct page *page) * not get another chance to clear PageMlocked. If we successfully * isolate the page and try_to_munlock() detects other VM_LOCKED vmas * mapping the page, it will restore the PageMlocked state, unless the page - * is mapped in a non-linear vma. So, we go ahead and SetPageMlocked(), + * is mapped in a non-linear vma. So, we go ahead and ClearPageMlocked(), * perhaps redundantly. * If we lose the isolation race, and the page is mapped by other VM_LOCKED * vmas, we'll detect this in vmscan--via try_to_munlock() or try_to_unmap() * either of which will restore the PageMlocked state by calling * mlock_vma_page() above, if it can grab the vma's mmap sem. */ -static void munlock_vma_page(struct page *page) +void munlock_vma_page(struct page *page) { BUG_ON(!PageLocked(page));
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