Date: Mon, 08 Jan 2018 10:39:47 -0800 From: John Baldwin <jhb@freebsd.org> To: freebsd-current@freebsd.org Cc: Michael Jung <mikej@mikej.com> Subject: Re: witness_lock_list_get: witness exhausted Message-ID: <1684681.MCyL5Ev91y@ralph.baldwin.cx> In-Reply-To: <6eecc842ba7a37af6b2ffe146dfd91da@mikej.com> References: <6eecc842ba7a37af6b2ffe146dfd91da@mikej.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tuesday, November 28, 2017 02:46:03 PM Michael Jung wrote: > Hi! > > I've recently up'd my processor count on our poudriere box and have > started noticing the error > "witness_lock_list_get: witness exhausted" on the console. The kernel > *DOES NOT* crash but I > thought the report may be useful to someone. > > $ uname -a > FreeBSD poudriere 12.0-CURRENT FreeBSD 12.0-CURRENT #1 r325999: Sun Nov > 19 18:41:20 EST 2017 > mikej@poudriere:/usr/obj/usr/src/amd64.amd64/sys/GENERIC amd64 > > The machine is pretty busy running four poudriere build instances. > > last pid: 76584; load averages: 115.07, 115.96, 98.30 > > up 6+07:32:59 14:44:03 > 763 processes: 117 running, 581 sleeping, 2 zombie, 63 lock > CPU: 59.0% user, 0.0% nice, 40.7% system, 0.1% interrupt, 0.1% idle > Mem: 12G Active, 2003M Inact, 44G Wired, 29G Free > ARC: 28G Total, 11G MFU, 16G MRU, 122M Anon, 359M Header, 1184M Other > 25G Compressed, 32G Uncompressed, 1.24:1 Ratio > > Let me know what additional information I might supply. This just means that WITNESS stopped working because it ran out of pre-allocated objects. In particular the objects used to track how many locks are held by how many threads: /* * XXX: This is somewhat bogus, as we assume here that at most 2048 threads * will hold LOCK_NCHILDREN locks. We handle failure ok, and we should * probably be safe for the most part, but it's still a SWAG. */ #define LOCK_NCHILDREN 5 #define LOCK_CHILDCOUNT 2048 Probably the '2048' (max number of concurrent threads) needs to scale with MAXCPU. 2048 threads is probably a bit low on big x86 boxes. -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?1684681.MCyL5Ev91y>