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mm, thp: do not cause memcg oom for thp 

Commit 2516035499 ("mm, thp: remove __GFP_NORETRY from khugepaged and
madvised allocations") changed the page allocator to no longer detect
thp allocations based on __GFP_NORETRY.

It did not, however, modify the mem cgroup try_charge() path to avoid
oom kill for either khugepaged collapsing or thp faulting.  It is never
expected to oom kill a process to allocate a hugepage for thp; reclaim
is governed by the thp defrag mode and MADV_HUGEPAGE, but allocations
(and charging) should fallback instead of oom killing processes.

Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1803191409420.124411@chino.kir.corp.google.com
Fixes: 2516035499 ("mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations")
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Rientjes 2018-03-22 16:17:45 -07:00 committed by Linus Torvalds
parent 1c610d5f93
commit 9d3c3354bb
2 changed files with 9 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
mm/huge_memory.c
View File

@ -555,7 +555,8 @@ static int __do_huge_pmd_anonymous_page(struct vm_fault *vmf, struct page *page,
VM_BUG_ON_PAGE(!PageCompound(page), page);
if (mem_cgroup_try_charge(page, vma->vm_mm, gfp, &memcg, true)) {
if (mem_cgroup_try_charge(page, vma->vm_mm, gfp | __GFP_NORETRY, &memcg,
true)) {
put_page(page);
count_vm_event(THP_FAULT_FALLBACK);
return VM_FAULT_FALLBACK;
@ -1316,7 +1317,7 @@ alloc:
}
if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm,
huge_gfp, &memcg, true))) {
huge_gfp | __GFP_NORETRY, &memcg, true))) {
put_page(new_page);
split_huge_pmd(vma, vmf->pmd, vmf->address);
if (page)

8
mm/khugepaged.c
View File

@ -965,7 +965,9 @@ static void collapse_huge_page(struct mm_struct *mm,
goto out_nolock;
}
if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp, &memcg, true))) {
/* Do not oom kill for khugepaged charges */
if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp | __GFP_NORETRY,
&memcg, true))) {
result = SCAN_CGROUP_CHARGE_FAIL;
goto out_nolock;
}
@ -1324,7 +1326,9 @@ static void collapse_shmem(struct mm_struct *mm,
goto out;
}
if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp, &memcg, true))) {
/* Do not oom kill for khugepaged charges */
if (unlikely(mem_cgroup_try_charge(new_page, mm, gfp | __GFP_NORETRY,
&memcg, true))) {
result = SCAN_CGROUP_CHARGE_FAIL;
goto out;
}