Date:   Tue, 28 Mar 2023 16:20:53 -0700
To:     mm-commits@vger.kernel.org, zokeefe@google.com,
        stevensd@chromium.org, shy828301@gmail.com, hannes@cmpxchg.org,
        peterx@redhat.com, akpm@linux-foundation.org
From:   Andrew Morton <akpm@linux-foundation.org>
Subject: [merged mm-stable] mm-khugepaged-alloc_charge_hpage-take-care-of-mem-charge-errors.patch removed from -mm tree
Message-Id: <20230328232053.95610C433EF@smtp.kernel.org>
Precedence: bulk
Reply-To: linux-kernel@vger.kernel.org


The quilt patch titled
     Subject: mm/khugepaged: alloc_charge_hpage() take care of mem charge errors
has been removed from the -mm tree.  Its filename was
     mm-khugepaged-alloc_charge_hpage-take-care-of-mem-charge-errors.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Peter Xu <peterx@redhat.com>
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@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: David Stevens <stevensd@chromium.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 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
@@ -972,12 +972,19 @@ 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@redhat.com are

mm-hugetlb-fix-uffd-wr-protection-for-cow-optimization-path.patch
mm-hugetlb-fix-uffd-wr-protection-for-cow-optimization-path-v2.patch
mm-hugetlb-fix-uffd-wr-protection-for-cow-optimization-path-v3.patch
mm-uffd-uffd_feature_wp_unpopulated.patch
mm-uffd-uffd_feature_wp_unpopulated-fix.patch
selftests-mm-smoke-test-uffd_feature_wp_unpopulated.patch