From 98159aad451176a8a33aff4bc7c11b3804721df0 Mon Sep 17 00:00:00 2001 From: Longlong Xia Date: Sat, 28 Jan 2023 09:47:57 +0000 Subject: [PATCH] mm/swapfile: add cond_resched() in get_swap_pages() commit 7717fc1a12f88701573f9ed897cc4f6699c661e3 upstream. 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 Reviewed-by: "Huang, Ying" Cc: Chen Wandun Cc: Huang Ying Cc: Kefeng Wang Cc: Nanyong Sun Cc: Hugh Dickins Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/swapfile.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/swapfile.c b/mm/swapfile.c index 72e481aacd5df..b72908df52ac9 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1101,6 +1101,7 @@ 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: -- 2.39.5