This is a note to let you know that I've just added the patch titled mm/swapfile: add cond_resched() in get_swap_pages() to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mm-swapfile-add-cond_resched-in-get_swap_pages.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 7717fc1a12f88701573f9ed897cc4f6699c661e3 Mon Sep 17 00:00:00 2001 From: Longlong Xia <xialonglong1@xxxxxxxxxx> Date: Sat, 28 Jan 2023 09:47:57 +0000 Subject: mm/swapfile: add cond_resched() in get_swap_pages() From: Longlong Xia <xialonglong1@xxxxxxxxxx> 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@xxxxxxxxxx Signed-off-by: Longlong Xia <xialonglong1@xxxxxxxxxx> Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx> Cc: Chen Wandun <chenwandun@xxxxxxxxxx> Cc: Huang Ying <ying.huang@xxxxxxxxx> Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> Cc: Nanyong Sun <sunnanyong@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- mm/swapfile.c | 1 + 1 file changed, 1 insertion(+) --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -983,6 +983,7 @@ 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: Patches currently in stable-queue which might be from xialonglong1@xxxxxxxxxx are queue-4.14/mm-swapfile-add-cond_resched-in-get_swap_pages.patch