mm, thp: do not cause memcg oom for thp

Commit 2516035 ("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/[email protected] Fixes: 2516035 ("mm, thp: remove __GFP_NORETRY from khugepaged and madvised allocations") Signed-off-by: David Rientjes <[email protected]> Cc: "Kirill A. Shutemov" <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Vlastimil Babka <[email protected]> Cc: Johannes Weiner <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
natale-p · Mar 23, 2018 · 9d3c335 · 9d3c335
1 parent 1c610d5
commit 9d3c335
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Showing 2 changed files with 9 additions and 4 deletions.
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
@@ -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 @@ int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
 	}
 
 	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)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
@@ -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;
 	}