The quilt patch titled Subject: mm/swapfile: add cond_resched() in get_swap_pages() has been removed from the -mm tree. Its filename was mm-swapfile-add-cond_resched-in-get_swap_pages.patch

This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------ From: Longlong Xia xialonglong1@huawei.com Subject: mm/swapfile: add cond_resched() in get_swap_pages() Date: Sat, 28 Jan 2023 09:47:57 +0000

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 ---

mm/swapfile.c | 1 + 1 file changed, 1 insertion(+)

--- a/mm/swapfile.c~mm-swapfile-add-cond_resched-in-get_swap_pages +++ a/mm/swapfile.c @@ -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: _

Patches currently in -mm which might be from xialonglong1@huawei.com are

mm-swapfile-remove-pr_debug-in-get_swap_pages.patch