diff options
| author | Kefeng Wang <wangkefeng.wang@huawei.com> | 2024-04-18 21:56:44 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-05-05 17:53:42 -0700 |
| commit | 80e75021486bd2f6463259c4569e2eb7668ae953 (patch) | |
| tree | ecb9b5780263236d5b28e74f692158b525940ac8 /mm/swapfile.c | |
| parent | d21f996b02a027f8915e493ee01370c4610ed2e2 (diff) | |
mm: swapfile: check usable swap device in __folio_throttle_swaprate()
Skip blk_cgroup_congested() if there is no usable swap device since no
swapin/out will occur, Thereby avoid taking swap_lock. The difference
is shown below from perf date of CoW pagefault,
perf report -g -i perf.data.swapon | egrep "blk_cgroup_congested|__folio_throttle_swaprate"
1.01% 0.16% page_fault2_pro [kernel.kallsyms] [k] __folio_throttle_swaprate
0.83% 0.80% page_fault2_pro [kernel.kallsyms] [k] blk_cgroup_congested
perf report -g -i perf.data.swapoff | egrep "blk_cgroup_congested|__folio_throttle_swaprate"
0.15% 0.15% page_fault2_pro [kernel.kallsyms] [k] __folio_throttle_swaprate
Link: https://lkml.kernel.org/r/20240418135644.2736748-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/swapfile.c')
| -rw-r--r-- | mm/swapfile.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c index 28642c188c93..96606580ee09 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -2444,13 +2444,17 @@ static void reinsert_swap_info(struct swap_info_struct *p) spin_unlock(&swap_lock); } +static bool __has_usable_swap(void) +{ + return !plist_head_empty(&swap_active_head); +} + bool has_usable_swap(void) { - bool ret = true; + bool ret; spin_lock(&swap_lock); - if (plist_head_empty(&swap_active_head)) - ret = false; + ret = __has_usable_swap(); spin_unlock(&swap_lock); return ret; } @@ -3710,6 +3714,9 @@ void __folio_throttle_swaprate(struct folio *folio, gfp_t gfp) if (!(gfp & __GFP_IO)) return; + if (!__has_usable_swap()) + return; + if (!blk_cgroup_congested()) return; |