From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 77F97318139; Fri, 8 May 2026 21:29:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778275752; cv=none; b=Jk26V2ZDdue4eR+/kgVAvYMmZTXcpOjXxPVS8EZMf/G34E/QV/nAh4AUxjMXCJeYSRKaZnLBqBLLWqj2c/GQpf/BMgGUlXmfaG4ZM16u69kT377kc06W90nVc2X5+0VA3pwAzF8PNjwcCFqqtLgpYH6uU0meg00+c1Pn6upSnsI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778275752; c=relaxed/simple; bh=IOVcrk9REVLC/7YFQYwiNnSAENEwg1JIY8dDdJKSs9E=; h=Date:To:From:Subject:Message-Id; b=YK5HcgoRMGr9av9gQJwQouxjxUwsM6RRu8BunSqk/3aQpKWWI/bd70sqU0uZARtPMb5XFd+hQ832B23QkugJoNIcDbJVm1gpwFpAoY0SsOGMfu9KmrLRBXBeIy7lEskhPuDhKi3awkzJ5pSsUqDCmytWL7fsfXnZgiguK26+MzU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=L118ten7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="L118ten7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 101BEC2BCB0; Fri, 8 May 2026 21:29:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1778275752; bh=IOVcrk9REVLC/7YFQYwiNnSAENEwg1JIY8dDdJKSs9E=; h=Date:To:From:Subject:From; b=L118ten7lulb7j9iDO9BtH2YD8oEAuM7ttGyA3uw14njaNziaXsyEG7FlM/Wg606N BJC3LceVXSmptKkPUm0xUxZENkQL2JQ9ETGn6M7ARVIQyWKjF/2n0kAl1rduX7E8mX wLhEaizkzLeBSpf/BK8+17LbfMseGkOOBz/D6rsY= Date: Fri, 08 May 2026 14:29:11 -0700 To: mm-commits@vger.kernel.org,youngjun.park@lge.com,stable@vger.kernel.org,shikemeng@huaweicloud.com,nphamcs@gmail.com,kerayhuang@tencent.com,kasong@tencent.com,flyingpeng@tencent.com,chrisl@kernel.org,baoquan.he@linux.dev,baohua@kernel.org,albinwyang@tencent.com,huangzjsmile@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-swap-add-cond_resched-in-swap_reclaim_full_clusters-to-prevent-softlockup.patch added to mm-new branch Message-Id: <20260508212912.101BEC2BCB0@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/swap: add cond_resched() in swap_reclaim_full_clusters to prevent softlockup has been added to the -mm mm-new branch. Its filename is mm-swap-add-cond_resched-in-swap_reclaim_full_clusters-to-prevent-softlockup.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-swap-add-cond_resched-in-swap_reclaim_full_clusters-to-prevent-softlockup.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Zijiang Huang Subject: mm/swap: add cond_resched() in swap_reclaim_full_clusters to prevent softlockup Date: Wed, 6 May 2026 21:09:19 +0800 We hit a real softlockup in an internal stress test environment. The workload was LTP memory/swap stress on a large arm64 machine, with 320 CPUs, about 1TB memory and an 8.6GB swap device. The system was under heavy load and the swap device had a large number of full clusters. The softlockup was triggered during a stress test after about 3 days. So, add periodic cond_resched() calls during large full_clusters reclaim operations to prevent softlockup issues. Detailed call trace as follow: PID: 3817773 TASK: ffff0883bb28b780 CPU: 48 COMMAND: "kworker/48:7" #0 [ffff800080183d10] __crash_kexec at ffffa4c1361e5de4 #1 [ffff800080183d90] panic at ffffa4c1360d5e9c #2 [ffff800080183e20] watchdog_timer_fn at ffffa4c136231fa8 ... #16 [ffff8000c4ad3cb0] swap_cache_del_folio at ffffa4c1363e1614 #17 [ffff8000c4ad3ce0] __try_to_reclaim_swap at ffffa4c1363e4bfc #18 [ffff8000c4ad3d40] swap_reclaim_full_clusters at ffffa4c1363e5474 #19 [ffff8000c4ad3da0] swap_reclaim_work at ffffa4c1363e550c #20 [ffff8000c4ad3dc0] process_one_work at ffffa4c136102edc #21 [ffff8000c4ad3e10] worker_thread at ffffa4c136103398 #22 [ffff8000c4ad3e70] kthread at ffffa4c13610d95c Link: https://lore.kernel.org/20260506130919.2298807-1-kerayhuang@tencent.com Fixes: 5168a68eb78f ("mm, swap: avoid over reclaim of full clusters") Signed-off-by: Zijiang Huang Reviewed-by: Kairui Song Reviewed-by: Hao Peng Reviewed-by: albinwyang Reviewed-by: Baoquan He Acked-by: Chris Li Cc: Barry Song Cc: Kairui Song Cc: Kemeng Shi Cc: Nhat Pham Cc: Youngjun Park Cc: Signed-off-by: Andrew Morton --- mm/swapfile.c | 1 + 1 file changed, 1 insertion(+) --- a/mm/swapfile.c~mm-swap-add-cond_resched-in-swap_reclaim_full_clusters-to-prevent-softlockup +++ a/mm/swapfile.c @@ -1054,6 +1054,7 @@ static void swap_reclaim_full_clusters(s swap_cluster_unlock(ci); if (to_scan <= 0) break; + cond_resched(); } } _ Patches currently in -mm which might be from huangzjsmile@gmail.com are mm-swap-add-cond_resched-in-swap_reclaim_full_clusters-to-prevent-softlockup.patch