From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f169.google.com (mail-pf0-f169.google.com [209.85.192.169]) by kanga.kvack.org (Postfix) with ESMTP id 2296F6B0256 for ; Tue, 2 Feb 2016 11:21:46 -0500 (EST) Received: by mail-pf0-f169.google.com with SMTP id 65so107599876pfd.2 for ; Tue, 02 Feb 2016 08:21:46 -0800 (PST) Received: from mga02.intel.com (mga02.intel.com. [134.134.136.20]) by mx.google.com with ESMTP id os10si2715892pac.121.2016.02.02.08.21.45 for ; Tue, 02 Feb 2016 08:21:45 -0800 (PST) From: "Kirill A. Shutemov" Subject: [PATCHv2 1/2] mempolicy: do not try to queue pages from !vma_migratable() Date: Tue, 2 Feb 2016 19:21:00 +0300 Message-Id: <1454430061-116955-2-git-send-email-kirill.shutemov@linux.intel.com> In-Reply-To: <1454430061-116955-1-git-send-email-kirill.shutemov@linux.intel.com> References: <1454430061-116955-1-git-send-email-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Dmitry Vyukov Cc: Vlastimil Babka , David Rientjes , Naoya Horiguchi , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Maybe I miss some point, but I don't see a reason why we try to queue pages from non migratable VMAs. This testcase steps on VM_BUG_ON_PAGE() in isolate_lru_page(): #include #include #include #include #include #define SIZE 0x2000 int foo; int main() { int fd; char *p; unsigned long mask = 2; fd = open("/dev/sg0", O_RDWR); p = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_PRIVATE, fd, 0); /* Faultin pages */ foo = p[0] + p[0x1000]; mbind(p, SIZE, MPOL_BIND, &mask, 4, MPOL_MF_MOVE | MPOL_MF_STRICT); return 0; } The only case when we can queue pages from such VMA is MPOL_MF_STRICT plus MPOL_MF_MOVE or MPOL_MF_MOVE_ALL for VMA which has pages on LRU, but gfp mask is not sutable for migaration (see mapping_gfp_mask() check in vma_migratable()). That's looks like a bug to me. Let's filter out non-migratable vma at start of queue_pages_test_walk() and go to queue_pages_pte_range() only if MPOL_MF_MOVE or MPOL_MF_MOVE_ALL flag is set. Signed-off-by: Kirill A. Shutemov Reported-by: Dmitry Vyukov --- mm/mempolicy.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 27d135408a22..4c4187c0e1de 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -548,8 +548,7 @@ retry: goto retry; } - if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) - migrate_page_add(page, qp->pagelist, flags); + migrate_page_add(page, qp->pagelist, flags); } pte_unmap_unlock(pte - 1, ptl); cond_resched(); @@ -625,7 +624,7 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end, unsigned long endvma = vma->vm_end; unsigned long flags = qp->flags; - if (vma->vm_flags & VM_PFNMAP) + if (!vma_migratable(vma)) return 1; if (endvma > end) @@ -644,16 +643,13 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end, if (flags & MPOL_MF_LAZY) { /* Similar to task_numa_work, skip inaccessible VMAs */ - if (vma_migratable(vma) && - vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) + if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) change_prot_numa(vma, start, endvma); return 1; } - if ((flags & MPOL_MF_STRICT) || - ((flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) && - vma_migratable(vma))) - /* queue pages from current vma */ + /* queue pages from current vma */ + if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) return 0; return 1; } -- 2.7.0 -- 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