diff options
| author | Kairui Song <kasong@tencent.com> | 2025-03-14 00:59:31 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-03-16 22:06:43 -0700 |
| commit | 78524b05f1a3e16a5d00cc9c6259c41a9d6003ce (patch) | |
| tree | c9bf9018cb91fdc20e529013a1a37bc6eab624e5 /mm/zswap.c | |
| parent | 3123fb0a18d6c76b536a315b88553211cd3c2b1d (diff) | |
mm, swap: avoid redundant swap device pinning
Currently __read_swap_cache_async() has get/put_swap_device() calls to
increase/decrease a swap device reference to prevent swapoff. While some
of its callers have already held the swap device reference, e.g in
do_swap_page() and shmem_swapin_folio() where __read_swap_cache_async()
will finally called. Now there are only two callers not holding a swap
device reference, so make them hold a reference instead. And drop the
get/put_swap_device calls in __read_swap_cache_async. This should reduce
the overhead for swap in during page fault slightly.
Link: https://lkml.kernel.org/r/20250313165935.63303-4-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Matthew Wilcow (Oracle) <willy@infradead.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/zswap.c')
| -rw-r--r-- | mm/zswap.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/mm/zswap.c b/mm/zswap.c index 23365e76a3ce..8a1ded8fa973 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1051,14 +1051,20 @@ static int zswap_writeback_entry(struct zswap_entry *entry, struct folio *folio; struct mempolicy *mpol; bool folio_was_allocated; + struct swap_info_struct *si; struct writeback_control wbc = { .sync_mode = WB_SYNC_NONE, }; /* try to allocate swap cache folio */ + si = get_swap_device(swpentry); + if (!si) + return -EEXIST; + mpol = get_task_policy(current); folio = __read_swap_cache_async(swpentry, GFP_KERNEL, mpol, - NO_INTERLEAVE_INDEX, &folio_was_allocated, true); + NO_INTERLEAVE_INDEX, &folio_was_allocated, true); + put_swap_device(si); if (!folio) return -ENOMEM; |