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From: Baoquan He To: Zijiang Huang , akpm@linux-foundation.org, chrisl@kernel.org Cc: albinwyang@tencent.com, bhe@redhat.com, flyingpeng@tencent.com, kasong@tencent.com, kerayhuang@tencent.com, linux-mm@kvack.org Subject: Re: [PATCH v2] mm/swap: Add cond_resched() in swap_reclaim_full_clusters to prevent softlockup Message-ID: References: <20260506130919.2298807-1-kerayhuang@tencent.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260506130919.2298807-1-kerayhuang@tencent.com> X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 6A51080008 X-Rspam-User: X-Stat-Signature: atg7wfck7rpoqcuwumhp913px1psw6zy X-HE-Tag: 1778117715-218696 X-HE-Meta: U2FsdGVkX1+SkmigIX0R2TTxmSBFV7GETpDPK9jUAsE+j6FTkIPrI96WgZuLBaS2Cn3+j13F8R9leDPlMKsepHNqE43mIRzqO3zP10O46TpE1zVE8hyM3rd4dZDaEH2Kda2XclX+v/0SIeycdIlzhBHXg3gE/DZfQ0QOTqYdWgpckH6xaYNPDdcHviOkVy/W57CyVI9qRGVnUmsBAh2KtNYOvvghhlEzFjMX4dK3frPdTYR4YXMLFrShCmPe9EIBrgw0tIUhbYlszT1Hft7FOFyNSFHLM1R9WcNstd2/e4iKfX808h9qzOYT6H+23NKKNgl+xD8LIjXuVaA/9sMEsdyv6U0b6AbLUWoUo/oNqBxrTHbWualRjHNlQjYUta3VzO0w+3AEiXxxzjg6Xw/cByKUjA5Q95ZWaidIB+3kpY8PEXdfY+/Tq7Amw9kGsnB1G3gFFWhlIPE0KEFMc7CkygvuUZYNU2fvCCwfENaS2G6mY0Rg3IJLgcNWYjLo8uZI0R1uCkaiwcgub+0g8NEyyyc10b/VcWANP3TStQH25wvoohGylA7WKUw17VTZIX8adO0CrySxfBMHegivUiVriqRbz4Adedjbe38QX/9H+p4juULkrDoNZwenoagrVOk13nZDFC58PF4Pq5g5lMXhonE+C+TPati7GA1FpzctGuFw2f+EpyfcqfN8U21dhj7px8q/3OmEacz6prO0ueuy28kFvZbcNrY4llg063SrDpw65FPeZoHjrhNC5wepzxW0RqgY5ACsz/2eBPi71LoMjd2hQ3o3Zz3NF5fLFqCpzDlso3LnzfUpMNDLPJMYGEQeKr/OL7qXABnEh7vnmNiEyxL41Wr5R9Edow6wVBrzCL0vC9jAFVpVjGw0zOlYyd5ESujS99K6ZdVz1upLdwuG2X7FMBfDjk0aQRnk94pU7MxU6SUAo0T4NeXyNUzPjg1sZuNtGp8r6UuKS5FcMpO tMdp3VvX bKBkF9M5gpUysVsI5Qj/a8tiJOd8rdgar2f8NaEz/Zn2Dlbg5RGjaPIBIIPngw508f17zIRmaT1jx3LOCs0s8FJ/bIouwcudkr9JNbYb9Od18VVqamyuC8yijVszViirGx6k+B187Wdq/i/hu/q6m/ZctWpzZGj7E41P21ZGqyiMmm4VaAG/Kd0qihCuqdKB45/CZ/cH26q7RKesRCakiENY/7KiI6xJUbKSvyfb8ZcPuElgMQN1pUCiw4xtTl59kVmSAWkIaTIrXi4CWrkQFsSQI5+Igi+UdEKZp/fUvVVwRXMgzlJogjkmWPvpNYaARwz4LjzJdBqLNJWFXN6eMLz2btKU86o4cqybD Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 05/06/26 at 09:09pm, Zijiang Huang wrote: > 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 > > 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 > --- > mm/swapfile.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/swapfile.c b/mm/swapfile.c > index 9174f1eeffb0..74a1e324449d 100644 > --- a/mm/swapfile.c > +++ b/mm/swapfile.c > @@ -1054,6 +1054,7 @@ static void swap_reclaim_full_clusters(struct swap_info_struct *si, bool force) > swap_cluster_unlock(ci); > if (to_scan <= 0) > break; > + cond_resched(); > } > } LGTM, Reviewed-by: Baoquan He