From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Kirill A. Shutemov" Subject: Re: mm: another VM_BUG_ON_PAGE(PageTail(page)) Date: Fri, 29 Jan 2016 15:35:44 +0300 Message-ID: <20160129123544.GB146512@black.fi.intel.com> References: <20160128105136.GD2396@node.shutemov.name> <20160128114042.GE2396@node.shutemov.name> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mga11.intel.com ([192.55.52.93]:6680 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755290AbcA2Mft (ORCPT ); Fri, 29 Jan 2016 07:35:49 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Dmitry Vyukov Cc: "Kirill A. Shutemov" , Vlastimil Babka , Doug Gilbert , Andrew Morton , David Rientjes , Naoya Horiguchi , Shiraz Hashim , "linux-mm@kvack.org" , LKML , Hugh Dickins , Sasha Levin , syzkaller , Kostya Serebryany , Alexander Potapenko , linux-scsi >>From 691a961bb401c5815ed741dac63591efbc6027e3 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Fri, 29 Jan 2016 15:06:17 +0300 Subject: [PATCH 2/2] mempolicy: do not try to queue pages from !vma_migratable() Maybe I miss some point, but I don't see a reason why we try to queue pages from non migratable VMAs. 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 --- 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.rc3