From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 71C005F0001 for ; Mon, 2 Feb 2009 23:24:26 -0500 (EST) Received: by wf-out-1314.google.com with SMTP id 28so1889204wfc.11 for ; Mon, 02 Feb 2009 20:24:24 -0800 (PST) Date: Tue, 3 Feb 2009 13:24:05 +0900 From: MinChan Kim Subject: [PATCH v2] fix mlocked page counter mistmatch Message-ID: <20090203042405.GB16179@barrios-desktop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: owner-linux-mm@kvack.org To: Andrew Morton , linux mm Cc: KOSAKI Motohiro , linux kernel , Nick Piggin , Rik van Riel List-ID: When I tested following program, I found that mlocked counter is strange. It couldn't free some mlocked pages of test program. It is caused that try_to_unmap_file don't check real page mapping in vmas. That's because goal of address_space for file is to find all processes into which the file's specific interval is mapped. What I mean is that it's not related page but file's interval. Even if the page isn't really mapping at the vma, it returns SWAP_MLOCK since the vma have VM_LOCKED, then calls try_to_mlock_page. After all, mlocked counter is increased again. COWed anon page in a file-backed vma could be a such case. This patch resolves it. This patch is based on 2.6.28-rc2-mm1. -- my test program -- int main() { mlockall(MCL_CURRENT); return 0; } -- before -- root@barrios-target-linux:~# cat /proc/meminfo | egrep 'Mlo|Unev' Unevictable: 0 kB Mlocked: 0 kB -- after -- root@barrios-target-linux:~# cat /proc/meminfo | egrep 'Mlo|Unev' Unevictable: 8 kB Mlocked: 8 kB Signed-off-by: MinChan Kim Acked-by: Lee Schermerhorn Tested-by: Lee Schermerhorn --- mm/rmap.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 1099394..bd24b55 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1080,7 +1080,8 @@ static int try_to_unmap_file(struct page *page, int unlock, int migration) spin_lock(&mapping->i_mmap_lock); vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) { if (MLOCK_PAGES && unlikely(unlock)) { - if (!(vma->vm_flags & VM_LOCKED)) + if (!((vma->vm_flags & VM_LOCKED) && + page_mapped_in_vma(page, vma))) continue; /* must visit all vmas */ ret = SWAP_MLOCK; } else { -- 1.5.4.3 -- Kinds Regards MinChan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org