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b=MtUGYhygXM+sj4xbujiwGuhQ7DRWb75JoZbQGCaB9nEFcUEjHuXfhS6UzGl45IfRKKEYchBbkTlpO4UbYwChxU27w5vWnlpwHIi5YYRHWBnLToA9l1nsNV0KCYjScOrjw2kEXp9v3IILkifswfTPCeCFTXsrbXYqcE+0j3DV4Rs= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from IA1PR12MB6434.namprd12.prod.outlook.com (2603:10b6:208:3ae::10) by BL1PR12MB5825.namprd12.prod.outlook.com (2603:10b6:208:394::20) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.7741.36; Wed, 10 Jul 2024 12:03:59 +0000 Received: from IA1PR12MB6434.namprd12.prod.outlook.com ([fe80::dbf7:e40c:4ae9:8134]) by IA1PR12MB6434.namprd12.prod.outlook.com ([fe80::dbf7:e40c:4ae9:8134%3]) with mapi id 15.20.7741.033; Wed, 10 Jul 2024 12:03:59 +0000 Message-ID: <4307e984-a593-4495-b4cc-8ef509ddda03@amd.com> Date: Wed, 10 Jul 2024 17:33:47 +0530 User-Agent: Mozilla Thunderbird Subject: Re: Hard and soft lockups with FIO and LTP runs on a large system To: Yu Zhao , mjguzik@gmail.com, david@fromorbit.com, kent.overstreet@linux.dev Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, nikunj@amd.com, "Upadhyay, Neeraj" , Andrew Morton , David Hildenbrand , willy@infradead.org, vbabka@suse.cz, kinseyho@google.com, Mel Gorman , linux-fsdevel@vger.kernel.org References: Content-Language: en-US From: Bharata B Rao In-Reply-To: Content-Type: text/plain; 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Below is once such soft lockup. >> Below preemptirqsoff trace points to preemption being disabled for more >> than 10s and the lock in picture is lruvec spinlock. > > Also if you could try the other patch (mglru.patch) please. It should > help reduce unnecessary rotations from deactivate_file_folio(), which > in turn should reduce the contention on the LRU lock for MGLRU. Thanks. With mglru.patch on a MGLRU-enabled system, the below latency trace record is no longer seen for a 30hr workload run. > >> # tracer: preemptirqsoff >> # >> # preemptirqsoff latency trace v1.1.5 on 6.10.0-rc3-mglru-irqstrc >> # -------------------------------------------------------------------- >> # latency: 10382682 us, #4/4, CPU#128 | (M:desktop VP:0, KP:0, SP:0 >> HP:0 #P:512) >> # ----------------- >> # | task: fio-2701523 (uid:0 nice:0 policy:0 rt_prio:0) >> # ----------------- >> # => started at: deactivate_file_folio >> # => ended at: deactivate_file_folio >> # >> # >> # _------=> CPU# >> # / _-----=> irqs-off/BH-disabled >> # | / _----=> need-resched >> # || / _---=> hardirq/softirq >> # ||| / _--=> preempt-depth >> # |||| / _-=> migrate-disable >> # ||||| / delay >> # cmd pid |||||| time | caller >> # \ / |||||| \ | / >> fio-2701523 128...1. 0us$: deactivate_file_folio >> <-deactivate_file_folio >> fio-2701523 128.N.1. 10382681us : deactivate_file_folio >> <-deactivate_file_folio >> fio-2701523 128.N.1. 10382683us : tracer_preempt_on >> <-deactivate_file_folio >> fio-2701523 128.N.1. 10382691us : >> => deactivate_file_folio >> => mapping_try_invalidate >> => invalidate_mapping_pages >> => invalidate_bdev >> => blkdev_common_ioctl >> => blkdev_ioctl >> => __x64_sys_ioctl >> => x64_sys_call >> => do_syscall_64 >> => entry_SYSCALL_64_after_hwframe However the contention now has shifted to inode_hash_lock. Around 55 softlockups in ilookup() were observed: # tracer: preemptirqsoff # # preemptirqsoff latency trace v1.1.5 on 6.10.0-rc3-trnmglru # -------------------------------------------------------------------- # latency: 10620430 us, #4/4, CPU#260 | (M:desktop VP:0, KP:0, SP:0 HP:0 #P:512) # ----------------- # | task: fio-3244715 (uid:0 nice:0 policy:0 rt_prio:0) # ----------------- # => started at: ilookup # => ended at: ilookup # # # _------=> CPU# # / _-----=> irqs-off/BH-disabled # | / _----=> need-resched # || / _---=> hardirq/softirq # ||| / _--=> preempt-depth # |||| / _-=> migrate-disable # ||||| / delay # cmd pid |||||| time | caller # \ / |||||| \ | / fio-3244715 260...1. 0us$: _raw_spin_lock <-ilookup fio-3244715 260.N.1. 10620429us : _raw_spin_unlock <-ilookup fio-3244715 260.N.1. 10620430us : tracer_preempt_on <-ilookup fio-3244715 260.N.1. 10620440us : => _raw_spin_unlock => ilookup => blkdev_get_no_open => blkdev_open => do_dentry_open => vfs_open => path_openat => do_filp_open => do_sys_openat2 => __x64_sys_openat => x64_sys_call => do_syscall_64 => entry_SYSCALL_64_after_hwframe It appears that scalability issues with inode_hash_lock has been brought up multiple times in the past and there were patches to address the same. https://lore.kernel.org/all/20231206060629.2827226-9-david@fromorbit.com/ https://lore.kernel.org/lkml/20240611173824.535995-2-mjguzik@gmail.com/ CC'ing FS folks/list for awareness/comments. Regards, Bharata.