The patch titled
Subject: mm/khugepaged: cleanup memcg uncharge for failure path
has been added to the -mm mm-unstable branch. Its filename is
mm-khugepaged-cleanup-memcg-uncharge-for-failure-path.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-khugepaged-cleanup-memcg-uncharge-for-failure-path.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: cleanup memcg uncharge for failure path
Date: Fri, 3 Mar 2023 10:12:18 -0500
Explicit memcg uncharging is not needed when the memcg accounting has the
same lifespan of the page/folio. That becomes the case for khugepaged
after Yang & Zach's recent rework so the hpage will be allocated for each
collapse rather than being cached.
Cleanup the explicit memcg uncharge in khugepaged failure path and leave
that for put_page().
Link: https://lkml.kernel.org/r/20230303151218.311015-1-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Suggested-by: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Reviewed-by: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Reviewed-by: Yang Shi <shy828301@xxxxxxxxx>
Cc: David Stevens <stevensd@xxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/khugepaged.c~mm-khugepaged-cleanup-memcg-uncharge-for-failure-path
+++ a/mm/khugepaged.c
@@ -1136,10 +1136,8 @@ static int collapse_huge_page(struct mm_
out_up_write:
mmap_write_unlock(mm);
out_nolock:
- if (hpage) {
- mem_cgroup_uncharge(page_folio(hpage));
+ if (hpage)
put_page(hpage);
- }
trace_mm_collapse_huge_page(mm, result == SCAN_SUCCEED, result);
return result;
}
@@ -2145,10 +2143,8 @@ xa_unlocked:
unlock_page(hpage);
out:
VM_BUG_ON(!list_empty(&pagelist));
- if (hpage) {
- mem_cgroup_uncharge(page_folio(hpage));
+ if (hpage)
put_page(hpage);
- }
trace_mm_khugepaged_collapse_file(mm, hpage, index, is_shmem, addr, file, nr, result);
return result;
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-khugepaged-alloc_charge_hpage-take-care-of-mem-charge-errors.patch
mm-khugepaged-cleanup-memcg-uncharge-for-failure-path.patch
