Remove the nc_time and nc_ticks elements from struct namecache, and
provide struct namecache_ts which is the old struct namecache. Only allocate struct namecache_ts if non-null struct timespec *tsp was passed to cache_enter_time, otherwise use struct namecache. Change struct namecache allocation and deallocation macros into static functions, since logic becomes somewhat twisty. Provide accessor for the nc_name member of struct namecache to hide difference between struct namecache and namecache_ts. The aim of the change is to not waste 20 bytes per small namecache entry. Reviewed by: jhb MFC after: 2 weeks X-MFC-note: after r230394
This commit is contained in:
kib
parent
8e3e986346
commit
fb6370fb86
@ -97,13 +97,35 @@ struct namecache {
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TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */
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struct vnode *nc_dvp; /* vnode of parent of name */
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struct vnode *nc_vp; /* vnode the name refers to */
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struct timespec nc_time; /* timespec provided by fs */
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int nc_ticks; /* ticks value when entry was added */
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u_char nc_flag; /* flag bits */
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u_char nc_nlen; /* length of name */
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char nc_name[0]; /* segment name + nul */
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};
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/*
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* struct namecache_ts repeats struct namecache layout up to the
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* nc_nlen member.
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*/
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struct namecache_ts {
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LIST_ENTRY(namecache) nc_hash; /* hash chain */
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LIST_ENTRY(namecache) nc_src; /* source vnode list */
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TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */
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struct vnode *nc_dvp; /* vnode of parent of name */
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struct vnode *nc_vp; /* vnode the name refers to */
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u_char nc_flag; /* flag bits */
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u_char nc_nlen; /* length of name */
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struct timespec nc_time; /* timespec provided by fs */
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int nc_ticks; /* ticks value when entry was added */
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char nc_name[0]; /* segment name + nul */
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};
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/*
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* Flags in namecache.nc_flag
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*/
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#define NCF_WHITE 0x01
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#define NCF_ISDOTDOT 0x02
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#define NCF_TS 0x04
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/*
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* Name caching works as follows:
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*
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@ -166,20 +188,50 @@ RW_SYSINIT(vfscache, &cache_lock, "Name Cache");
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* fit in the small cache.
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*/
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static uma_zone_t cache_zone_small;
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static uma_zone_t cache_zone_small_ts;
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static uma_zone_t cache_zone_large;
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#define CACHE_PATH_CUTOFF 35
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#define CACHE_ZONE_SMALL (sizeof(struct namecache) + CACHE_PATH_CUTOFF \
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+ 1)
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#define CACHE_ZONE_LARGE (sizeof(struct namecache) + NAME_MAX + 1)
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#define cache_alloc(len) uma_zalloc(((len) <= CACHE_PATH_CUTOFF) ? \
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cache_zone_small : cache_zone_large, M_WAITOK)
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#define cache_free(ncp) do { \
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if (ncp != NULL) \
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uma_zfree(((ncp)->nc_nlen <= CACHE_PATH_CUTOFF) ? \
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cache_zone_small : cache_zone_large, (ncp)); \
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} while (0)
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static struct namecache *
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cache_alloc(int len, int ts)
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{
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if (len > CACHE_PATH_CUTOFF)
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return (uma_zalloc(cache_zone_large, M_WAITOK));
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if (ts)
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return (uma_zalloc(cache_zone_small_ts, M_WAITOK));
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else
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return (uma_zalloc(cache_zone_small, M_WAITOK));
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}
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static void
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cache_free(struct namecache *ncp)
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{
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int ts;
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if (ncp == NULL)
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return;
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ts = ncp->nc_flag & NCF_TS;
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if (ncp->nc_nlen <= CACHE_PATH_CUTOFF) {
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if (ts)
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uma_zfree(cache_zone_small_ts, ncp);
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else
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uma_zfree(cache_zone_small, ncp);
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} else
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uma_zfree(cache_zone_large, ncp);
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}
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static char *
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nc_get_name(struct namecache *ncp)
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{
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struct namecache_ts *ncp_ts;
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if ((ncp->nc_flag & NCF_TS) == 0)
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return (ncp->nc_name);
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ncp_ts = (struct namecache_ts *)ncp;
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return (ncp_ts->nc_name);
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}
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static int doingcache = 1; /* 1 => enable the cache */
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SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0,
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@ -235,12 +287,6 @@ static int vn_fullpath1(struct thread *td, struct vnode *vp, struct vnode *rdir,
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static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries");
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/*
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* Flags in namecache.nc_flag
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*/
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#define NCF_WHITE 0x01
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#define NCF_ISDOTDOT 0x02
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#ifdef DIAGNOSTIC
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/*
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* Grab an atomic snapshot of the name cache hash chain lengths
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@ -346,10 +392,10 @@ cache_zap(ncp)
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#ifdef KDTRACE_HOOKS
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if (ncp->nc_vp != NULL) {
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SDT_PROBE(vfs, namecache, zap, done, ncp->nc_dvp,
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ncp->nc_name, ncp->nc_vp, 0, 0);
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nc_get_name(ncp), ncp->nc_vp, 0, 0);
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} else {
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SDT_PROBE(vfs, namecache, zap_negative, done, ncp->nc_dvp,
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ncp->nc_name, 0, 0, 0);
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nc_get_name(ncp), 0, 0, 0);
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}
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#endif
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vp = NULL;
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@ -460,10 +506,17 @@ retry_wlocked:
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dvp, cnp->cn_nameptr, *vpp);
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SDT_PROBE(vfs, namecache, lookup, hit, dvp, "..",
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*vpp, 0, 0);
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if (tsp != NULL)
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*tsp = ncp->nc_time;
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if (ticksp != NULL)
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*ticksp = ncp->nc_ticks;
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if (tsp != NULL) {
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KASSERT((ncp->nc_flag & NCF_TS) != 0,
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("No NCF_TS"));
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*tsp = ((struct namecache_ts *)ncp)->nc_time;
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}
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if (ticksp != NULL) {
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KASSERT((ncp->nc_flag & NCF_TS) != 0,
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("No NCF_TS"));
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*ticksp = ((struct namecache_ts *)ncp)->
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nc_ticks;
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}
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goto success;
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}
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}
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@ -473,7 +526,7 @@ retry_wlocked:
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LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
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numchecks++;
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if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
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!bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
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!bcmp(nc_get_name(ncp), cnp->cn_nameptr, ncp->nc_nlen))
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break;
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}
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@ -508,12 +561,16 @@ retry_wlocked:
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*vpp = ncp->nc_vp;
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CTR4(KTR_VFS, "cache_lookup(%p, %s) found %p via ncp %p",
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dvp, cnp->cn_nameptr, *vpp, ncp);
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SDT_PROBE(vfs, namecache, lookup, hit, dvp, ncp->nc_name,
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SDT_PROBE(vfs, namecache, lookup, hit, dvp, nc_get_name(ncp),
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*vpp, 0, 0);
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if (tsp != NULL)
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*tsp = ncp->nc_time;
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if (ticksp != NULL)
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*ticksp = ncp->nc_ticks;
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if (tsp != NULL) {
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KASSERT((ncp->nc_flag & NCF_TS) != 0, ("No NCF_TS"));
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*tsp = ((struct namecache_ts *)ncp)->nc_time;
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}
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if (ticksp != NULL) {
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KASSERT((ncp->nc_flag & NCF_TS) != 0, ("No NCF_TS"));
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*ticksp = ((struct namecache_ts *)ncp)->nc_ticks;
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}
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goto success;
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}
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@ -543,12 +600,16 @@ negative_success:
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nchstats.ncs_neghits++;
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if (ncp->nc_flag & NCF_WHITE)
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cnp->cn_flags |= ISWHITEOUT;
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SDT_PROBE(vfs, namecache, lookup, hit_negative, dvp, ncp->nc_name,
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SDT_PROBE(vfs, namecache, lookup, hit_negative, dvp, nc_get_name(ncp),
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0, 0, 0);
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if (tsp != NULL)
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*tsp = ncp->nc_time;
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if (ticksp != NULL)
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*ticksp = ncp->nc_ticks;
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if (tsp != NULL) {
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KASSERT((ncp->nc_flag & NCF_TS) != 0, ("No NCF_TS"));
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*tsp = ((struct namecache_ts *)ncp)->nc_time;
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}
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if (ticksp != NULL) {
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KASSERT((ncp->nc_flag & NCF_TS) != 0, ("No NCF_TS"));
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*ticksp = ((struct namecache_ts *)ncp)->nc_ticks;
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}
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CACHE_WUNLOCK();
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return (ENOENT);
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@ -642,6 +703,7 @@ cache_enter_time(dvp, vp, cnp, tsp)
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struct timespec *tsp;
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{
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struct namecache *ncp, *n2;
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struct namecache_ts *n3;
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struct nchashhead *ncpp;
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uint32_t hash;
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int flag;
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@ -708,18 +770,19 @@ cache_enter_time(dvp, vp, cnp, tsp)
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* Calculate the hash key and setup as much of the new
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* namecache entry as possible before acquiring the lock.
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*/
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ncp = cache_alloc(cnp->cn_namelen);
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ncp = cache_alloc(cnp->cn_namelen, tsp != NULL);
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ncp->nc_vp = vp;
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ncp->nc_dvp = dvp;
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ncp->nc_flag = flag;
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if (tsp != NULL)
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ncp->nc_time = *tsp;
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else
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timespecclear(&ncp->nc_time);
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ncp->nc_ticks = ticks;
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if (tsp != NULL) {
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n3 = (struct namecache_ts *)ncp;
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n3->nc_time = *tsp;
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n3->nc_ticks = ticks;
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n3->nc_flag |= NCF_TS;
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}
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len = ncp->nc_nlen = cnp->cn_namelen;
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hash = fnv_32_buf(cnp->cn_nameptr, len, FNV1_32_INIT);
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strlcpy(ncp->nc_name, cnp->cn_nameptr, len + 1);
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strlcpy(nc_get_name(ncp), cnp->cn_nameptr, len + 1);
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hash = fnv_32_buf(&dvp, sizeof(dvp), hash);
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CACHE_WLOCK();
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@ -732,9 +795,16 @@ cache_enter_time(dvp, vp, cnp, tsp)
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LIST_FOREACH(n2, ncpp, nc_hash) {
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if (n2->nc_dvp == dvp &&
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n2->nc_nlen == cnp->cn_namelen &&
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!bcmp(n2->nc_name, cnp->cn_nameptr, n2->nc_nlen)) {
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n2->nc_time = ncp->nc_time;
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n2->nc_ticks = ncp->nc_ticks;
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!bcmp(nc_get_name(n2), cnp->cn_nameptr, n2->nc_nlen)) {
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if (tsp != NULL) {
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KASSERT((n2->nc_flag & NCF_TS) != 0,
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("no NCF_TS"));
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n3 = (struct namecache_ts *)n2;
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n3->nc_time =
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((struct namecache_ts *)ncp)->nc_time;
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n3->nc_ticks =
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((struct namecache_ts *)ncp)->nc_ticks;
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}
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CACHE_WUNLOCK();
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cache_free(ncp);
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return;
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@ -792,12 +862,12 @@ cache_enter_time(dvp, vp, cnp, tsp)
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*/
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if (vp) {
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TAILQ_INSERT_HEAD(&vp->v_cache_dst, ncp, nc_dst);
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SDT_PROBE(vfs, namecache, enter, done, dvp, ncp->nc_name, vp,
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0, 0);
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SDT_PROBE(vfs, namecache, enter, done, dvp, nc_get_name(ncp),
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vp, 0, 0);
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} else {
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TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst);
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SDT_PROBE(vfs, namecache, enter_negative, done, dvp,
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ncp->nc_name, 0, 0, 0);
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nc_get_name(ncp), 0, 0, 0);
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}
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if (numneg * ncnegfactor > numcache) {
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ncp = TAILQ_FIRST(&ncneg);
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@ -819,10 +889,15 @@ nchinit(void *dummy __unused)
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TAILQ_INIT(&ncneg);
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cache_zone_small = uma_zcreate("S VFS Cache", CACHE_ZONE_SMALL, NULL,
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NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
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cache_zone_large = uma_zcreate("L VFS Cache", CACHE_ZONE_LARGE, NULL,
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NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
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cache_zone_small = uma_zcreate("S VFS Cache",
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sizeof(struct namecache) + CACHE_PATH_CUTOFF + 1,
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NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
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cache_zone_small_ts = uma_zcreate("STS VFS Cache",
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sizeof(struct namecache_ts) + CACHE_PATH_CUTOFF + 1,
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NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
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cache_zone_large = uma_zcreate("L VFS Cache",
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sizeof(struct namecache_ts) + NAME_MAX + 1,
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NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
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nchashtbl = hashinit(desiredvnodes * 2, M_VFSCACHE, &nchash);
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}
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@ -1126,9 +1201,9 @@ vn_vptocnp_locked(struct vnode **vp, struct ucred *cred, char *buf,
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return (error);
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}
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*buflen -= ncp->nc_nlen;
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memcpy(buf + *buflen, ncp->nc_name, ncp->nc_nlen);
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memcpy(buf + *buflen, nc_get_name(ncp), ncp->nc_nlen);
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SDT_PROBE(vfs, namecache, fullpath, hit, ncp->nc_dvp,
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ncp->nc_name, vp, 0, 0);
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nc_get_name(ncp), vp, 0, 0);
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dvp = *vp;
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*vp = ncp->nc_dvp;
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vref(*vp);
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@ -1301,7 +1376,7 @@ vn_commname(struct vnode *vp, char *buf, u_int buflen)
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return (ENOENT);
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}
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l = min(ncp->nc_nlen, buflen - 1);
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memcpy(buf, ncp->nc_name, l);
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memcpy(buf, nc_get_name(ncp), l);
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CACHE_RUNLOCK();
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buf[l] = '\0';
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return (0);
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