Commit 23519073 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
Browse files

oom-reaper: use madvise_dontneed() logic to decide if unmap the VMA 

Logic on whether we can reap pages from the VMA should match what we
have in madvise_dontneed().  In particular, we should skip, VM_PFNMAP
VMAs, but we don't now.

Let's just extract condition on which we can shoot down pagesi from a
VMA with MADV_DONTNEED into separate function and use it in both places.

Link: http://lkml.kernel.org/r/20170118122429.43661-4-kirill.shutemov@linux.intel.com


Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ecf1385d

mm/internal.h

+5 −0
Original line number Diff line number Diff line
@@ -43,6 +43,11 @@ int do_swap_page(struct vm_fault *vmf); 
void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,

		unsigned long floor, unsigned long ceiling);



static inline bool can_madv_dontneed_vma(struct vm_area_struct *vma)

{

	return !(vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP));

}



void unmap_page_range(struct mmu_gather *tlb,

			     struct vm_area_struct *vma,

			     unsigned long addr, unsigned long end,

mm/madvise.c

+3 −1
Original line number Diff line number Diff line
@@ -25,6 +25,8 @@ 


#include <asm/tlb.h>



#include "internal.h"



/*

 * Any behaviour which results in changes to the vma->vm_flags needs to

 * take mmap_sem for writing. Others, which simply traverse vmas, need
@@ -474,7 +476,7 @@ static long madvise_dontneed(struct vm_area_struct *vma, 
			     unsigned long start, unsigned long end)

{

	*prev = vma;

	if (vma->vm_flags & (VM_LOCKED|VM_HUGETLB|VM_PFNMAP))

	if (!can_madv_dontneed_vma(vma))

		return -EINVAL;



	madvise_userfault_dontneed(vma, prev, start, end);

mm/oom_kill.c

+1 −8
Original line number Diff line number Diff line
@@ -508,14 +508,7 @@ static bool __oom_reap_task_mm(struct task_struct *tsk, struct mm_struct *mm) 


	tlb_gather_mmu(&tlb, mm, 0, -1);

	for (vma = mm->mmap ; vma; vma = vma->vm_next) {

		if (is_vm_hugetlb_page(vma))

			continue;



		/*

		 * mlocked VMAs require explicit munlocking before unmap.

		 * Let's keep it simple here and skip such VMAs.

		 */

		if (vma->vm_flags & VM_LOCKED)

		if (!can_madv_dontneed_vma(vma))

			continue;



		/*

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