mm, thp: do not cause memcg oom for thp (9d3c3354) · Commits · 戴 / test

Commit ("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: ("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>

mm/huge_memory.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -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)

mm/khugepaged.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}

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