6.15-stable review patch. If anyone has any objections, please let me know.
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From: Kemeng Shi shikemeng@huaweicloud.com
commit 4f78252da887ee7e9d1875dd6e07d9baa936c04f upstream.
Patch series "Some randome fixes and cleanups to swapfile".
Patch 0-3 are some random fixes. Patch 4 is a cleanup. More details can be found in respective patches.
This patch (of 4):
When folio_alloc_swap() encounters a failure in either mem_cgroup_try_charge_swap() or add_to_swap_cache(), nr_swap_pages counter is not decremented for allocated entry. However, the following put_swap_folio() will increase nr_swap_pages counter unpairly and lead to an imbalance.
Move nr_swap_pages decrement from folio_alloc_swap() to swap_range_alloc() to pair the nr_swap_pages counting.
Link: https://lkml.kernel.org/r/20250522122554.12209-1-shikemeng@huaweicloud.com Link: https://lkml.kernel.org/r/20250522122554.12209-2-shikemeng@huaweicloud.com Fixes: 0ff67f990bd4 ("mm, swap: remove swap slot cache") Signed-off-by: Kemeng Shi shikemeng@huaweicloud.com Reviewed-by: Kairui Song kasong@tencent.com Reviewed-by: Baoquan He bhe@redhat.com Cc: Johannes Weiner hannes@cmpxchg.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/swapfile.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1115,6 +1115,7 @@ static void swap_range_alloc(struct swap if (vm_swap_full()) schedule_work(&si->reclaim_work); } + atomic_long_sub(nr_entries, &nr_swap_pages); }
static void swap_range_free(struct swap_info_struct *si, unsigned long offset, @@ -1313,7 +1314,6 @@ int folio_alloc_swap(struct folio *folio if (add_to_swap_cache(folio, entry, gfp | __GFP_NOMEMALLOC, NULL)) goto out_free;
- atomic_long_sub(size, &nr_swap_pages); return 0;
out_free: