Date: Fri, 27 Sep 2019 19:12:20 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r352810 - head/sys/kern Message-ID: <201909271912.x8RJCKvn046034@repo.freebsd.org>
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Author: mjg Date: Fri Sep 27 19:12:20 2019 New Revision: 352810 URL: https://svnweb.freebsd.org/changeset/base/352810 Log: cache: stop recalculating upper limit each time a new entry is added Sponsored by: The FreeBSD Foundation Modified: head/sys/kern/vfs_cache.c Modified: head/sys/kern/vfs_cache.c ============================================================================== --- head/sys/kern/vfs_cache.c Fri Sep 27 19:07:11 2019 (r352809) +++ head/sys/kern/vfs_cache.c Fri Sep 27 19:12:20 2019 (r352810) @@ -214,7 +214,7 @@ SYSCTL_ULONG(_debug, OID_AUTO, numcache, CTLFLAG_RD, & static u_long __exclusive_cache_line numcachehv;/* number of cache entries with vnodes held */ SYSCTL_ULONG(_debug, OID_AUTO, numcachehv, CTLFLAG_RD, &numcachehv, 0, "Number of namecache entries with vnodes held"); -u_int __read_mostly ncsizefactor = 2; +u_int ncsizefactor = 2; SYSCTL_UINT(_vfs, OID_AUTO, ncsizefactor, CTLFLAG_RW, &ncsizefactor, 0, "Size factor for namecache"); static u_int __read_mostly ncpurgeminvnodes; @@ -223,6 +223,7 @@ SYSCTL_UINT(_vfs, OID_AUTO, ncpurgeminvnodes, CTLFLAG_ static u_int __read_mostly ncneghitsrequeue = 8; SYSCTL_UINT(_vfs, OID_AUTO, ncneghitsrequeue, CTLFLAG_RW, &ncneghitsrequeue, 0, "Number of hits to requeue a negative entry in the LRU list"); +static u_int __read_mostly ncsize; /* the size as computed on creation or resizing */ struct nchstats nchstats; /* cache effectiveness statistics */ @@ -1713,7 +1714,7 @@ cache_enter_time(struct vnode *dvp, struct vnode *vp, * Avoid blowout in namecache entries. */ lnumcache = atomic_fetchadd_long(&numcache, 1) + 1; - if (__predict_false(lnumcache >= desiredvnodes * ncsizefactor)) { + if (__predict_false(lnumcache >= ncsize)) { atomic_add_long(&numcache, -1); return; } @@ -1969,6 +1970,7 @@ nchinit(void *dummy __unused) NULL, NULL, NULL, NULL, UMA_ALIGNOF(struct namecache_ts), UMA_ZONE_ZINIT); + ncsize = desiredvnodes * ncsizefactor; nchashtbl = hashinit(desiredvnodes * 2, M_VFSCACHE, &nchash); ncbuckethash = cache_roundup_2(mp_ncpus * mp_ncpus) - 1; if (ncbuckethash < 7) /* arbitrarily chosen to avoid having one lock */ @@ -2024,8 +2026,10 @@ cache_changesize(int newmaxvnodes) u_long new_nchash, old_nchash; struct namecache *ncp; uint32_t hash; + int newncsize; int i; + newncsize = newmaxvnodes * ncsizefactor; newmaxvnodes = cache_roundup_2(newmaxvnodes * 2); if (newmaxvnodes < numbucketlocks) newmaxvnodes = numbucketlocks; @@ -2055,6 +2059,7 @@ cache_changesize(int newmaxvnodes) LIST_INSERT_HEAD(NCHHASH(hash), ncp, nc_hash); } } + ncsize = newncsize; cache_unlock_all_buckets(); cache_unlock_all_vnodes(); free(old_nchashtbl, M_VFSCACHE);
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