diff options
Diffstat (limited to 'sys/kern/vfs_cache.c')
| -rw-r--r-- | sys/kern/vfs_cache.c | 68 |
1 files changed, 66 insertions, 2 deletions
diff --git a/sys/kern/vfs_cache.c b/sys/kern/vfs_cache.c index bf792cd4256f..2299e7034484 100644 --- a/sys/kern/vfs_cache.c +++ b/sys/kern/vfs_cache.c @@ -98,6 +98,10 @@ static u_long numneg; /* number of cache entries allocated */ SYSCTL_ULONG(_debug, OID_AUTO, numneg, CTLFLAG_RD, &numneg, 0, ""); static u_long numcache; /* number of cache entries allocated */ SYSCTL_ULONG(_debug, OID_AUTO, numcache, CTLFLAG_RD, &numcache, 0, ""); +static u_long numcachehv; /* number of cache entries with vnodes held */ +SYSCTL_ULONG(_debug, OID_AUTO, numcachehv, CTLFLAG_RD, &numcachehv, 0, ""); +static u_long numcachepl; /* number of cache purge for leaf entries */ +SYSCTL_ULONG(_debug, OID_AUTO, numcachepl, CTLFLAG_RD, &numcachepl, 0, ""); struct nchstats nchstats; /* cache effectiveness statistics */ static int doingcache = 1; /* 1 => enable the cache */ @@ -227,8 +231,10 @@ cache_zap(ncp) { LIST_REMOVE(ncp, nc_hash); LIST_REMOVE(ncp, nc_src); - if (LIST_EMPTY(&ncp->nc_dvp->v_cache_src)) + if (LIST_EMPTY(&ncp->nc_dvp->v_cache_src)) { vdrop(ncp->nc_dvp); + numcachehv--; + } if (ncp->nc_vp) { TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst, ncp, nc_dst); } else { @@ -404,8 +410,10 @@ cache_enter(dvp, vp, cnp) hash = fnv_32_buf(&dvp->v_id, sizeof(dvp->v_id), hash); ncpp = NCHHASH(hash); LIST_INSERT_HEAD(ncpp, ncp, nc_hash); - if (LIST_EMPTY(&dvp->v_cache_src)) + if (LIST_EMPTY(&dvp->v_cache_src)) { vhold(dvp); + numcachehv++; + } LIST_INSERT_HEAD(&dvp->v_cache_src, ncp, nc_src); if (vp) { TAILQ_INSERT_HEAD(&vp->v_cache_dst, ncp, nc_dst); @@ -491,6 +499,62 @@ cache_purgevfs(mp) } /* + * Flush all dirctory entries with no child directories held in + * the cache. + * + * Since we need to check it anyway, we will flush all the invalid + * entries at the same time. + */ +void +cache_purgeleafdirs(ndir) + int ndir; +{ + struct nchashhead *ncpp; + struct namecache *ncp, *nnp, *ncpc, *nnpc; + struct vnode *dvp; + + /* Scan hash tables for applicable entries */ + for (ncpp = &nchashtbl[nchash]; ncpp >= nchashtbl && ndir > 0; ncpp--) { + for (ncp = LIST_FIRST(ncpp); ncp != 0 && ndir > 0; ncp = nnp) { + nnp = LIST_NEXT(ncp, nc_hash); + if (ncp->nc_dvp != 0) { + /* + * Skip over if nc_dvp of this cache holds + * a child directory, or the hold count of + * nc_dvp is greater than 1 (in which case + * nc_dvp is likely to be the working + * directory of a process). + */ + if (ncp->nc_dvp->v_holdcnt > 1) + continue; + for (ncpc = LIST_FIRST(&ncp->nc_dvp->v_cache_src); + ncpc != 0; ncpc = nnpc) { + nnpc = LIST_NEXT(ncpc, nc_src); + if (ncpc->nc_vp != 0 && ncpc->nc_vp->v_type == VDIR) + break; + } + if (ncpc == 0) { + /* + * Zap all of this directory's children, + * held in ncp->nc_dvp->v_cache_src. + */ + dvp = ncp->nc_dvp; + while (!LIST_EMPTY(&dvp->v_cache_src)) + cache_zap(LIST_FIRST(&dvp->v_cache_src)); + + ndir--; + + /* Restart in case where nnp is reclaimed. */ + nnp = LIST_FIRST(ncpp); + continue; + } + } + } + } + numcachepl++; +} + +/* * Perform canonical checks and cache lookup and pass on to filesystem * through the vop_cachedlookup only if needed. */ |