Commit 9e0d0ddfbc0e for kernel

commit 9e0d0ddfbc0e3491da7e2db73faa08d8d4f322b2
Author: Alexandre Ghiti <alex@ghiti.fr>
Date:   Fri Mar 20 06:05:59 2026 +0100

    mm/swap: fix swap cache memcg accounting

    The swap readahead path was recently refactored and while doing this, the
    order between the charging of the folio in the memcg and the addition of
    the folio in the swap cache was inverted.

    Since the accounting of the folio is done while adding the folio to the
    swap cache and the folio is not charged in the memcg yet, the accounting
    is then done at the node level, which is wrong.

    Fix this by charging the folio in the memcg before adding it to the swap cache.

    Link: https://lkml.kernel.org/r/20260320050601.1833108-1-alex@ghiti.fr
    Fixes: 2732acda82c9 ("mm, swap: use swap cache as the swap in synchronize layer")
    Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
    Acked-by: Kairui Song <kasong@tencent.com>
    Acked-by: Johannes Weiner <hannes@cmpxchg.org>
    Reviewed-by: Nhat Pham <nphamcs@gmail.com>
    Acked-by: Chris Li <chrisl@kernel.org>
    Cc: Alexandre Ghiti <alex@ghiti.fr>
    Cc: Baoquan He <bhe@redhat.com>
    Cc: Barry Song <baohua@kernel.org>
    Cc: Kemeng Shi <shikemeng@huaweicloud.com>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/swap_state.c b/mm/swap_state.c
index 6d0eef7470be..48aff2c917c0 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -494,6 +494,10 @@ static struct folio *__swap_cache_prepare_and_add(swp_entry_t entry,

 	__folio_set_locked(folio);
 	__folio_set_swapbacked(folio);
+
+	if (!charged && mem_cgroup_swapin_charge_folio(folio, NULL, gfp, entry))
+		goto failed;
+
 	for (;;) {
 		ret = swap_cache_add_folio(folio, entry, &shadow);
 		if (!ret)
@@ -514,11 +518,6 @@ static struct folio *__swap_cache_prepare_and_add(swp_entry_t entry,
 			goto failed;
 	}

-	if (!charged && mem_cgroup_swapin_charge_folio(folio, NULL, gfp, entry)) {
-		swap_cache_del_folio(folio);
-		goto failed;
-	}
-
 	memcg1_swapin(entry, folio_nr_pages(folio));
 	if (shadow)
 		workingset_refault(folio, shadow);