Date: Tue, 31 Oct 2023 16:42:10 +0100 From: Mateusz Guzik <mjguzik@gmail.com> To: John F Carr <jfc@mit.edu> Cc: Freebsd fs <freebsd-fs@freebsd.org> Subject: Re: vnode_init took over 6 minutes Message-ID: <CAGudoHG301oJy76s_ONwxv9oAo1Y_vNi0BALPh03Kpw=JaByfA@mail.gmail.com> In-Reply-To: <8F17FEC3-C3CB-410D-ACEC-ADD12B3A747A@mit.edu> References: <67FBC292-E83D-4171-BE79-D28D5578F031@mit.edu> <CAGudoHFv0y9-4NMYCnhQh%2BvbQj0dReofGpCx_zejqz1RKDGNcA@mail.gmail.com> <8F17FEC3-C3CB-410D-ACEC-ADD12B3A747A@mit.edu>
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On 10/31/23, John F Carr <jfc@mit.edu> wrote: > > >> On Oct 31, 2023, at 10:16, Mateusz Guzik <mjguzik@gmail.com> wrote: >> >> On 10/31/23, John F Carr <jfc@mit.edu> wrote: >>> During a poudriere build control-T showed an awk process was stuck >>> for over 6 minutes trying to acquire a lock in vnode_init. >>> >>> load: 8.58 cmd: awk 51238 [running] 392.88r 0.00u 392.88s 100% 2604k >>> __mtx_lock_sleep+0xf8 __mtx_lock_flags+0xa4 vnode_init+0xc3 >>> keg_alloc_slab+0x277 zone_import+0x143 cache_alloc+0x3ed >>> cache_alloc_retry+0x23 getnewvnode_reserve+0x20 zfs_zget+0x1f >>> zfs_dirent_lookup+0x16d zfs_dirlook+0x7f zfs_lookup+0x3e0 >>> zfs_freebsd_cachedlookup+0x74 vfs_cache_lookup+0xa7 >>> cache_fplookup_noentry+0x241 cache_fplookup+0x575 namei+0x1ea >>> vn_open_cred+0x48d >>> >>> The stack trace was the same for several minutes. System CPU time was >>> increasing. >>> >>> Address vnode_init+0xc3 corresponds to the mtx_lock call here. >>> >>> vp->v_holdcnt = VHOLD_NO_SMR; >>> vp->v_type = VNON; >>> mtx_lock(&vnode_list_mtx); >>> TAILQ_INSERT_BEFORE(vnode_list_free_marker, vp, v_vnodelist); >>> mtx_unlock(&vnode_list_mtx); >>> return (0); >>> >>> Address __mtx_lock_sleep+0xf8 is the instruction after a call to >>> lock_delay. >>> >>> ps says the command line was >>> >>> /usr/bin/awk -f /usr/bin/awk >>> old-default/2023-10-31_08h21m03s/.poudriere.builders >>> old-default/2023-10-31_08h21m03s/.poudriere.buildname ... >>> >>> with the full list of input files exceeding the ~2KB command line length >>> limit of ps. >>> "/usr/bin/awk" is probably not the real second argument. It would cause >>> an >>> immediate syntax error. >>> >>> The hang resolved within a few more minutes and poudriere is continuing >>> happily. >>> >>> I have never seen such behavior before. Code in vfs_subr.c tries not to >>> hold the >>> vnode_list_mtx lock for too long. >>> >>> Any thoughts? >>> >>> >>> FreeBSD 13.2-STABLE up through commit b180f0040f95, 24 core 48 thread >>> Zen >>> 2, >>> zfs pool on SSD connected via 12 Gbps SAS with cache on NVME, 160 GB >>> RAM. >>> >> >> what does "sysctl vfs.vnode" say >> >> >> -- >> Mateusz Guzik <mjguzik gmail.com> > > With the builds now complete, > > vfs.vnode.vnlru.uma_reclaim_calls: 0 > vfs.vnode.vnlru.kicks: 0 > vfs.vnode.vnlru.max_free_per_call: 10000 > vfs.vnode.vnlru.failed_runs: 0 > vfs.vnode.vnlru.direct_recycles_free: 152871194 > vfs.vnode.vnlru.recycles_free: 77190881 > vfs.vnode.vnlru.recycles: 0 > vfs.vnode.stats.alloc_sleeps: 0 > vfs.vnode.stats.free: 1269702 > vfs.vnode.stats.skipped_requeues: 9375158 > vfs.vnode.stats.created: 235594976 > vfs.vnode.stats.count: 1407640 > vfs.vnode.param.wantfree: 681059 > vfs.vnode.param.limit: 2724237 > > Uptime is 11 days, mostly with low I/O rates. > > please add the uma stats: "sysctl vm.uma.VNODE" -- Mateusz Guzik <mjguzik gmail.com>
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