The patch titled
Subject: mm/khugepaged: alloc_charge_hpage() take care of mem charge errors
has been added to the -mm mm-unstable branch. Its filename is
mm-khugepaged-alloc_charge_hpage-take-care-of-mem-charge-errors.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-khugepaged-alloc_charge_hpage-take-care-of-mem-charge-errors.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Peter Xu <peterx@xxxxxxxxxx>
Subject: mm/khugepaged: alloc_charge_hpage() take care of mem charge errors
Date: Wed, 22 Feb 2023 14:52:47 -0500
If memory charge failed, instead of returning the hpage but with an error,
allow the function to cleanup the folio properly, which is normally what a
function should do in this case - either return successfully, or return
with no side effect of partial runs with an indicated error.
This will also avoid the caller calling mem_cgroup_uncharge()
unnecessarily with either anon or shmem path (even if it's safe to do so).
Link: https://lkml.kernel.org/r/20230222195247.791227-1-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Reviewed-by: David Stevens <stevensd@xxxxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Yang Shi <shy828301@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/khugepaged.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
--- a/mm/khugepaged.c~mm-khugepaged-alloc_charge_hpage-take-care-of-mem-charge-errors
+++ a/mm/khugepaged.c
@@ -1063,12 +1063,19 @@ static int alloc_charge_hpage(struct pag
gfp_t gfp = (cc->is_khugepaged ? alloc_hugepage_khugepaged_gfpmask() :
GFP_TRANSHUGE);
int node = hpage_collapse_find_target_node(cc);
+ struct folio *folio;
if (!hpage_collapse_alloc_page(hpage, gfp, node, &cc->alloc_nmask))
return SCAN_ALLOC_HUGE_PAGE_FAIL;
- if (unlikely(mem_cgroup_charge(page_folio(*hpage), mm, gfp)))
+
+ folio = page_folio(*hpage);
+ if (unlikely(mem_cgroup_charge(folio, mm, gfp))) {
+ folio_put(folio);
+ *hpage = NULL;
return SCAN_CGROUP_CHARGE_FAIL;
+ }
count_memcg_page_event(*hpage, THP_COLLAPSE_ALLOC);
+
return SCAN_SUCCEED;
}
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-khugepaged-alloc_charge_hpage-take-care-of-mem-charge-errors.patch
