From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH] mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check To: Konstantin Khlebnikov , linux-mm@kvack.org, Andrew Morton References: <145961146490.28194.16019687861681349309.stgit@zurg> Cc: Dmitry Vyukov , Andrea Arcangeli , linux-kernel@vger.kernel.org, stable From: Vlastimil Babka Message-ID: <57025FD3.4060004@suse.cz> Date: Mon, 4 Apr 2016 14:36:35 +0200 MIME-Version: 1.0 In-Reply-To: <145961146490.28194.16019687861681349309.stgit@zurg> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: On 04/02/2016 05:37 PM, Konstantin Khlebnikov wrote: > Khugepaged detects own VMAs by checking vm_file and vm_ops but this > way it cannot distinguish private /dev/zero mappings from other special > mappings like /dev/hpet which has no vm_ops and popultes PTEs in mmap. > > This fixes false-positive VM_BUG_ON and prevents installing THP where > they are not expected. > > Signed-off-by: Konstantin Khlebnikov > Reported-by: Dmitry Vyukov > Link: http://lkml.kernel.org/r/CACT4Y+ZmuZMV5CjSFOeXviwQdABAgT7T+StKfTqan9YDtgEi5g@mail.gmail.com > Fixes: 78f11a255749 ("mm: thp: fix /dev/zero MAP_PRIVATE and vm_flags cleanups") > Cc: stable Acked-by: Vlastimil Babka -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Sun, 3 Apr 2016 01:05:28 +0300 From: "Kirill A. Shutemov" To: Konstantin Khlebnikov Cc: linux-mm@kvack.org, Andrew Morton , Dmitry Vyukov , Andrea Arcangeli , linux-kernel@vger.kernel.org, stable Subject: Re: [PATCH] mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check Message-ID: <20160402220528.GA7977@node.shutemov.name> References: <145961146490.28194.16019687861681349309.stgit@zurg> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <145961146490.28194.16019687861681349309.stgit@zurg> Sender: owner-linux-mm@kvack.org List-ID: On Sat, Apr 02, 2016 at 06:37:44PM +0300, Konstantin Khlebnikov wrote: > Khugepaged detects own VMAs by checking vm_file and vm_ops but this > way it cannot distinguish private /dev/zero mappings from other special > mappings like /dev/hpet which has no vm_ops and popultes PTEs in mmap. > > This fixes false-positive VM_BUG_ON and prevents installing THP where > they are not expected. > > Signed-off-by: Konstantin Khlebnikov > Reported-by: Dmitry Vyukov > Link: http://lkml.kernel.org/r/CACT4Y+ZmuZMV5CjSFOeXviwQdABAgT7T+StKfTqan9YDtgEi5g@mail.gmail.com > Fixes: 78f11a255749 ("mm: thp: fix /dev/zero MAP_PRIVATE and vm_flags cleanups") > Cc: stable Looks good to me. Acked-by: Kirill A. Shutemov -- Kirill A. Shutemov -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: [PATCH] mm/huge_memory: replace VM_NO_THP VM_BUG_ON with actual VMA check From: Konstantin Khlebnikov To: linux-mm@kvack.org, Andrew Morton Cc: Dmitry Vyukov , Andrea Arcangeli , linux-kernel@vger.kernel.org, stable Date: Sat, 02 Apr 2016 18:37:44 +0300 Message-ID: <145961146490.28194.16019687861681349309.stgit@zurg> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: Khugepaged detects own VMAs by checking vm_file and vm_ops but this way it cannot distinguish private /dev/zero mappings from other special mappings like /dev/hpet which has no vm_ops and popultes PTEs in mmap. This fixes false-positive VM_BUG_ON and prevents installing THP where they are not expected. Signed-off-by: Konstantin Khlebnikov Reported-by: Dmitry Vyukov Link: http://lkml.kernel.org/r/CACT4Y+ZmuZMV5CjSFOeXviwQdABAgT7T+StKfTqan9YDtgEi5g@mail.gmail.com Fixes: 78f11a255749 ("mm: thp: fix /dev/zero MAP_PRIVATE and vm_flags cleanups") Cc: stable --- mm/huge_memory.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 86f9f8b82f8e..93de199ba0f1 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1960,10 +1960,9 @@ int khugepaged_enter_vma_merge(struct vm_area_struct *vma, * page fault if needed. */ return 0; - if (vma->vm_ops) + if (vma->vm_ops || (vm_flags & VM_NO_THP)) /* khugepaged not yet working on file or special mappings */ return 0; - VM_BUG_ON_VMA(vm_flags & VM_NO_THP, vma); hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK; hend = vma->vm_end & HPAGE_PMD_MASK; if (hstart < hend) @@ -2352,8 +2351,7 @@ static bool hugepage_vma_check(struct vm_area_struct *vma) return false; if (is_vma_temporary_stack(vma)) return false; - VM_BUG_ON_VMA(vma->vm_flags & VM_NO_THP, vma); - return true; + return !(vma->vm_flags & VM_NO_THP); } static void collapse_huge_page(struct mm_struct *mm, -- 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