Author: kib
Date: Sun Jan 22 01:11:06 2012
New Revision: 230441
URL: http://svn.freebsd.org/changeset/base/230441
Log:
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
Modified:
head/sys/kern/vfs_cache.c
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Sat Jan 21 22:18:33 2012 (r230440)
+++ head/sys/kern/vfs_cache.c Sun Jan 22 01:11:06 2012 (r230441)
@@ -97,14 +97,36 @@ struct namecache {
TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */
struct vnode *nc_dvp; /* vnode of parent of name */
struct vnode *nc_vp; /* vnode the name refers to */
- struct timespec nc_time; /* timespec provided by fs */
- int nc_ticks; /* ticks value when entry was added */
u_char nc_flag; /* flag bits */
u_char nc_nlen; /* length of name */
char nc_name[0]; /* segment name + nul */
};
/*
+ * struct namecache_ts repeats struct namecache layout up to the
+ * nc_nlen member.
+ */
+struct namecache_ts {
+ LIST_ENTRY(namecache) nc_hash; /* hash chain */
+ LIST_ENTRY(namecache) nc_src; /* source vnode list */
+ TAILQ_ENTRY(namecache) nc_dst; /* destination vnode list */
+ struct vnode *nc_dvp; /* vnode of parent of name */
+ struct vnode *nc_vp; /* vnode the name refers to */
+ u_char nc_flag; /* flag bits */
+ u_char nc_nlen; /* length of name */
+ struct timespec nc_time; /* timespec provided by fs */
+ int nc_ticks; /* ticks value when entry was added */
+ char nc_name[0]; /* segment name + nul */
+};
+
+/*
+ * Flags in namecache.nc_flag
+ */
+#define NCF_WHITE 0x01
+#define NCF_ISDOTDOT 0x02
+#define NCF_TS 0x04
+
+/*
* Name caching works as follows:
*
* Names found by directory scans are retained in a cache
@@ -166,20 +188,50 @@ RW_SYSINIT(vfscache, &cache_lock, "Name
* fit in the small cache.
*/
static uma_zone_t cache_zone_small;
+static uma_zone_t cache_zone_small_ts;
static uma_zone_t cache_zone_large;
#define CACHE_PATH_CUTOFF 35
-#define CACHE_ZONE_SMALL (sizeof(struct namecache) +
CACHE_PATH_CUTOFF \
- + 1)
-#define CACHE_ZONE_LARGE (sizeof(struct namecache) + NAME_MAX +
1)
-
-#define cache_alloc(len) uma_zalloc(((len) <= CACHE_PATH_CUTOFF) ? \
- cache_zone_small : cache_zone_large, M_WAITOK)
-#define cache_free(ncp) do { \
- if (ncp != NULL) \
- uma_zfree(((ncp)->nc_nlen <= CACHE_PATH_CUTOFF) ? \
- cache_zone_small : cache_zone_large, (ncp)); \
-} while (0)
+
+static struct namecache *
+cache_alloc(int len, int ts)
+{
+
+ if (len > CACHE_PATH_CUTOFF)
+ return (uma_zalloc(cache_zone_large, M_WAITOK));
+ if (ts)
+ return (uma_zalloc(cache_zone_small_ts, M_WAITOK));
+ else
+ return (uma_zalloc(cache_zone_small, M_WAITOK));
+}
+
+static void
+cache_free(struct namecache *ncp)
+{
+ int ts;
+
+ if (ncp == NULL)
+ return;
+ ts = ncp->nc_flag & NCF_TS;
+ if (ncp->nc_nlen <= CACHE_PATH_CUTOFF) {
+ if (ts)
+ uma_zfree(cache_zone_small_ts, ncp);
+ else
+ uma_zfree(cache_zone_small, ncp);
+ } else
+ uma_zfree(cache_zone_large, ncp);
+}
+
+static char *
+nc_get_name(struct namecache *ncp)
+{
+ struct namecache_ts *ncp_ts;
+
+ if ((ncp->nc_flag & NCF_TS) == 0)
+ return (ncp->nc_name);
+ ncp_ts = (struct namecache_ts *)ncp;
+ return (ncp_ts->nc_name);
+}
static int doingcache = 1; /* 1 => enable the cache */
SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0,
@@ -235,12 +287,6 @@ static int vn_fullpath1(struct thread *t
static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries");
-/*
- * Flags in namecache.nc_flag
- */
-#define NCF_WHITE 0x01
-#define NCF_ISDOTDOT 0x02
-
#ifdef DIAGNOSTIC
/*
* Grab an atomic snapshot of the name cache hash chain lengths
@@ -346,10 +392,10 @@ cache_zap(ncp)
#ifdef KDTRACE_HOOKS
if (ncp->nc_vp != NULL) {
SDT_PROBE(vfs, namecache, zap, done, ncp->nc_dvp,
- ncp->nc_name, ncp->nc_vp, 0, 0);
+ nc_get_name(ncp), ncp->nc_vp, 0, 0);
} else {
SDT_PROBE(vfs, namecache, zap_negative, done, ncp->nc_dvp,
- ncp->nc_name, 0, 0, 0);
+ nc_get_name(ncp), 0, 0, 0);
}
#endif
vp = NULL;
@@ -460,10 +506,17 @@ retry_wlocked:
dvp, cnp->cn_nameptr, *vpp);
SDT_PROBE(vfs, namecache, lookup, hit, dvp, "..",
*vpp, 0, 0);
- if (tsp != NULL)
- *tsp = ncp->nc_time;
- if (ticksp != NULL)
- *ticksp = ncp->nc_ticks;
+ if (tsp != NULL) {
+ KASSERT((ncp->nc_flag & NCF_TS) != 0,
+ ("No NCF_TS"));
+ *tsp = ((struct namecache_ts *)ncp)->nc_time;
+ }
+ if (ticksp != NULL) {
+ KASSERT((ncp->nc_flag & NCF_TS) != 0,
+ ("No NCF_TS"));
+ *ticksp = ((struct namecache_ts *)ncp)->
+ nc_ticks;
+ }
goto success;
}
}
@@ -473,7 +526,7 @@ retry_wlocked:
LIST_FOREACH(ncp, (NCHHASH(hash)), nc_hash) {
numchecks++;
if (ncp->nc_dvp == dvp && ncp->nc_nlen == cnp->cn_namelen &&
- !bcmp(ncp->nc_name, cnp->cn_nameptr, ncp->nc_nlen))
+ !bcmp(nc_get_name(ncp), cnp->cn_nameptr, ncp->nc_nlen))
break;
}
@@ -508,12 +561,16 @@ retry_wlocked:
*vpp = ncp->nc_vp;
CTR4(KTR_VFS, "cache_lookup(%p, %s) found %p via ncp %p",
dvp, cnp->cn_nameptr, *vpp, ncp);
- SDT_PROBE(vfs, namecache, lookup, hit, dvp, ncp->nc_name,
+ SDT_PROBE(vfs, namecache, lookup, hit, dvp, nc_get_name(ncp),
*vpp, 0, 0);
- if (tsp != NULL)
- *tsp = ncp->nc_time;
- if (ticksp != NULL)
- *ticksp = ncp->nc_ticks;
+ if (tsp != NULL) {
+ KASSERT((ncp->nc_flag & NCF_TS) != 0, ("No NCF_TS"));
+ *tsp = ((struct namecache_ts *)ncp)->nc_time;
+ }
+ if (ticksp != NULL) {
+ KASSERT((ncp->nc_flag & NCF_TS) != 0, ("No NCF_TS"));
+ *ticksp = ((struct namecache_ts *)ncp)->nc_ticks;
+ }
goto success;
}
@@ -543,12 +600,16 @@ negative_success:
nchstats.ncs_neghits++;
if (ncp->nc_flag & NCF_WHITE)
cnp->cn_flags |= ISWHITEOUT;
- SDT_PROBE(vfs, namecache, lookup, hit_negative, dvp, ncp->nc_name,
+ SDT_PROBE(vfs, namecache, lookup, hit_negative, dvp, nc_get_name(ncp),
0, 0, 0);
- if (tsp != NULL)
- *tsp = ncp->nc_time;
- if (ticksp != NULL)
- *ticksp = ncp->nc_ticks;
+ if (tsp != NULL) {
+ KASSERT((ncp->nc_flag & NCF_TS) != 0, ("No NCF_TS"));
+ *tsp = ((struct namecache_ts *)ncp)->nc_time;
+ }
+ if (ticksp != NULL) {
+ KASSERT((ncp->nc_flag & NCF_TS) != 0, ("No NCF_TS"));
+ *ticksp = ((struct namecache_ts *)ncp)->nc_ticks;
+ }
CACHE_WUNLOCK();
return (ENOENT);
@@ -642,6 +703,7 @@ cache_enter_time(dvp, vp, cnp, tsp)
struct timespec *tsp;
{
struct namecache *ncp, *n2;
+ struct namecache_ts *n3;
struct nchashhead *ncpp;
uint32_t hash;
int flag;
@@ -708,18 +770,19 @@ cache_enter_time(dvp, vp, cnp, tsp)
* Calculate the hash key and setup as much of the new
* namecache entry as possible before acquiring the lock.
*/
- ncp = cache_alloc(cnp->cn_namelen);
+ ncp = cache_alloc(cnp->cn_namelen, tsp != NULL);
ncp->nc_vp = vp;
ncp->nc_dvp = dvp;
ncp->nc_flag = flag;
- if (tsp != NULL)
- ncp->nc_time = *tsp;
- else
- timespecclear(&ncp->nc_time);
- ncp->nc_ticks = ticks;
+ if (tsp != NULL) {
+ n3 = (struct namecache_ts *)ncp;
+ n3->nc_time = *tsp;
+ n3->nc_ticks = ticks;
+ n3->nc_flag |= NCF_TS;
+ }
len = ncp->nc_nlen = cnp->cn_namelen;
hash = fnv_32_buf(cnp->cn_nameptr, len, FNV1_32_INIT);
- strlcpy(ncp->nc_name, cnp->cn_nameptr, len + 1);
+ strlcpy(nc_get_name(ncp), cnp->cn_nameptr, len + 1);
hash = fnv_32_buf(&dvp, sizeof(dvp), hash);
CACHE_WLOCK();
@@ -732,9 +795,16 @@ cache_enter_time(dvp, vp, cnp, tsp)
LIST_FOREACH(n2, ncpp, nc_hash) {
if (n2->nc_dvp == dvp &&
n2->nc_nlen == cnp->cn_namelen &&
- !bcmp(n2->nc_name, cnp->cn_nameptr, n2->nc_nlen)) {
- n2->nc_time = ncp->nc_time;
- n2->nc_ticks = ncp->nc_ticks;
+ !bcmp(nc_get_name(n2), cnp->cn_nameptr, n2->nc_nlen)) {
+ if (tsp != NULL) {
+ KASSERT((n2->nc_flag & NCF_TS) != 0,
+ ("no NCF_TS"));
+ n3 = (struct namecache_ts *)n2;
+ n3->nc_time =
+ ((struct namecache_ts *)ncp)->nc_time;
+ n3->nc_ticks =
+ ((struct namecache_ts *)ncp)->nc_ticks;
+ }
CACHE_WUNLOCK();
cache_free(ncp);
return;
@@ -792,12 +862,12 @@ cache_enter_time(dvp, vp, cnp, tsp)
*/
if (vp) {
TAILQ_INSERT_HEAD(&vp->v_cache_dst, ncp, nc_dst);
- SDT_PROBE(vfs, namecache, enter, done, dvp, ncp->nc_name, vp,
- 0, 0);
+ SDT_PROBE(vfs, namecache, enter, done, dvp, nc_get_name(ncp),
+ vp, 0, 0);
} else {
TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst);
SDT_PROBE(vfs, namecache, enter_negative, done, dvp,
- ncp->nc_name, 0, 0, 0);
+ nc_get_name(ncp), 0, 0, 0);
}
if (numneg * ncnegfactor > numcache) {
ncp = TAILQ_FIRST(&ncneg);
@@ -819,10 +889,15 @@ nchinit(void *dummy __unused)
TAILQ_INIT(&ncneg);
- cache_zone_small = uma_zcreate("S VFS Cache", CACHE_ZONE_SMALL, NULL,
- NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
- cache_zone_large = uma_zcreate("L VFS Cache", CACHE_ZONE_LARGE, NULL,
- NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
+ cache_zone_small = uma_zcreate("S VFS Cache",
+ sizeof(struct namecache) + CACHE_PATH_CUTOFF + 1,
+ NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
+ cache_zone_small_ts = uma_zcreate("STS VFS Cache",
+ sizeof(struct namecache_ts) + CACHE_PATH_CUTOFF + 1,
+ NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
+ cache_zone_large = uma_zcreate("L VFS Cache",
+ sizeof(struct namecache_ts) + NAME_MAX + 1,
+ NULL, NULL, NULL, NULL, UMA_ALIGN_PTR, UMA_ZONE_ZINIT);
nchashtbl = hashinit(desiredvnodes * 2, M_VFSCACHE, &nchash);
}
@@ -1126,9 +1201,9 @@ vn_vptocnp_locked(struct vnode **vp, str
return (error);
}
*buflen -= ncp->nc_nlen;
- memcpy(buf + *buflen, ncp->nc_name, ncp->nc_nlen);
+ memcpy(buf + *buflen, nc_get_name(ncp), ncp->nc_nlen);
SDT_PROBE(vfs, namecache, fullpath, hit, ncp->nc_dvp,
- ncp->nc_name, vp, 0, 0);
+ nc_get_name(ncp), vp, 0, 0);
dvp = *vp;
*vp = ncp->nc_dvp;
vref(*vp);
@@ -1301,7 +1376,7 @@ vn_commname(struct vnode *vp, char *buf,
return (ENOENT);
}
l = min(ncp->nc_nlen, buflen - 1);
- memcpy(buf, ncp->nc_name, l);
+ memcpy(buf, nc_get_name(ncp), l);
CACHE_RUNLOCK();
buf[l] = '\0';
return (0);
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