Commit 94c02ad7 authored by Peter Xu's avatar Peter Xu Committed by Andrew Morton
Browse files

mm/khugepaged: alloc_charge_hpage() take care of mem charge errors 

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@redhat.com


Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Reviewed-by: default avatarDavid Stevens <stevensd@chromium.org>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: default avatarYang Shi <shy828301@gmail.com>
Reviewed-by: default avatarZach O'Keefe <zokeefe@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 12318566

mm/khugepaged.c

+8 −1
Original line number Diff line number Diff line
@@ -972,12 +972,19 @@ 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;

}