If memory charge failed, the caller shouldn't call mem_cgroup_uncharge(). Let alloc_charge_hpage() handle the error itself and clear hpage properly if mem charge fails.
Cc: Johannes Weiner hannes@cmpxchg.org Cc: Yang Shi shy828301@gmail.com Cc: David Stevens stevensd@chromium.org Cc: stable@vger.kernel.org Fixes: 9d82c69438d0 ("mm: memcontrol: convert anon and file-thp to new mem_cgroup_charge() API") Signed-off-by: Peter Xu peterx@redhat.com --- mm/khugepaged.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 8dbc39896811..941d1c7ea910 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1063,12 +1063,19 @@ static int alloc_charge_hpage(struct page **hpage, struct mm_struct *mm, 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; }