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authorKemeng Shi <shikemeng@huaweicloud.com>2025-05-22 20:25:51 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-08-15 16:39:35 +0200
commit795fead6bff8424757f0ac7b609db8d3d09b6b87 (patch)
tree3f847c28a114cd81335f515ad99be0a19e637d64 /mm
parent815c528b13f2bb9b3130c13bedeabf2351a68129 (diff)
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mm: swap: move nr_swap_pages counter decrement from folio_alloc_swap() to swap_range_alloc()
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>
Diffstat (limited to 'mm')
-rw-r--r--mm/swapfile.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index e03084725355..4f47ec9118f8 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1115,6 +1115,7 @@ static void swap_range_alloc(struct swap_info_struct *si,
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, gfp_t gfp)
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: