mm/swapfile: add cond_resched() in get_swap_pages()

The softlockup still occurs in get_swap_pages() under memory pressure.  64
CPU cores, 64GB memory, and 28 zram devices, the disksize of each zram
device is 50MB with same priority as si.  Use the stress-ng tool to
increase memory pressure, causing the system to oom frequently.

The plist_for_each_entry_safe() loops in get_swap_pages() could reach tens
of thousands of times to find available space (extreme case:
cond_resched() is not called in scan_swap_map_slots()).  Let's add
cond_resched() into get_swap_pages() when failed to find available space
to avoid softlockup.

Link: https://lkml.kernel.org/r/20230128094757.1060525-1-xialonglong1@huawei.com
Signed-off-by: Longlong Xia <xialonglong1@huawei.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Chen Wandun <chenwandun@huawei.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nanyong Sun <sunnanyong@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

This commit is contained in:

Longlong Xia

2023-01-28 09:47:57 +00:00

committed by

Andrew Morton

parent 993f57e027

commit 7717fc1a12

1 changed files with 1 additions and 0 deletions

									
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mm/swapfile.c

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				@ -1100,6 +1100,7 @@ start_over:

							goto check_out;

						pr_debug("scan_swap_map of si %d failed to find offset\n",

							si->type);

						cond_resched();

						spin_lock(&swap_avail_lock);

				nextsi:

mm/swapfile: add cond_resched() in get_swap_pages()

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mm/swapfile.c

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