Comments?
Thanks,
christos
Index: sys/namei.h
===================================================================
RCS file: /cvsroot/src/sys/sys/namei.h,v
retrieving revision 1.98
diff -u -p -u -r1.98 namei.h
--- sys/namei.h 3 Jun 2019 06:05:39 -0000 1.98
+++ sys/namei.h 10 Sep 2019 23:20:48 -0000
@@ -196,19 +196,9 @@ struct nameidata {
#endif
/*
+ * Namecache entry.
* This structure describes the elements in the cache of recent
- * names looked up by namei. NCHNAMLEN is sized to make structure
- * size a power of two to optimize allocations. Minimum reasonable
- * size is 15.
- */
-
-#define NCHNAMLEN 31 /* maximum name segment length we
bother with */
-
-/*
- * Namecache entry. This structure is arranged so that frequently
- * accessed and mostly read-only data is toward the front, with
- * infrequently accessed data and the lock towards the rear. The
- * lock is then more likely to be in a separate cache line.
+ * names looked up by namei.
*
* Locking rules:
*
@@ -225,14 +215,14 @@ struct namecache {
struct vnode *nc_dvp; /* N vnode of parent of name */
struct vnode *nc_vp; /* N vnode the name refers to */
int nc_flags; /* - copy of componentname ISWHITEOUT */
- char nc_nlen; /* - length of name */
- char nc_name[NCHNAMLEN]; /* - segment name */
void *nc_gcqueue; /* N queue for garbage collection */
- TAILQ_ENTRY(namecache) nc_lru; /* L psuedo-lru chain */
+ TAILQ_ENTRY(namecache) nc_lru; /* L pseudo-lru chain */
LIST_ENTRY(namecache) nc_dvlist;/* L dvp's list of cache entries */
LIST_ENTRY(namecache) nc_vlist; /* L vp's list of cache entries */
kmutex_t nc_lock; /* lock on this entry */
int nc_hittime; /* N last time scored a hit */
+ u_short nc_nlen; /* - length of name */
+ char nc_name[0]; /* - segment name */
};
#ifdef _KERNEL
Index: sys/namei.src
===================================================================
RCS file: /cvsroot/src/sys/sys/namei.src,v
retrieving revision 1.42
diff -u -p -u -r1.42 namei.src
--- sys/namei.src 3 Jun 2019 06:04:21 -0000 1.42
+++ sys/namei.src 10 Sep 2019 23:20:48 -0000
@@ -188,19 +188,9 @@ NAMEIFL PARAMASK 0x02ee300 /* mask of pa
#endif
/*
+ * Namecache entry.
* This structure describes the elements in the cache of recent
- * names looked up by namei. NCHNAMLEN is sized to make structure
- * size a power of two to optimize allocations. Minimum reasonable
- * size is 15.
- */
-
-#define NCHNAMLEN 31 /* maximum name segment length we
bother with */
-
-/*
- * Namecache entry. This structure is arranged so that frequently
- * accessed and mostly read-only data is toward the front, with
- * infrequently accessed data and the lock towards the rear. The
- * lock is then more likely to be in a separate cache line.
+ * names looked up by namei.
*
* Locking rules:
*
@@ -217,14 +207,14 @@ struct namecache {
struct vnode *nc_dvp; /* N vnode of parent of name */
struct vnode *nc_vp; /* N vnode the name refers to */
int nc_flags; /* - copy of componentname ISWHITEOUT */
- char nc_nlen; /* - length of name */
- char nc_name[NCHNAMLEN]; /* - segment name */
void *nc_gcqueue; /* N queue for garbage collection */
TAILQ_ENTRY(namecache) nc_lru; /* L psuedo-lru chain */
LIST_ENTRY(namecache) nc_dvlist;/* L dvp's list of cache entries */
LIST_ENTRY(namecache) nc_vlist; /* L vp's list of cache entries */
kmutex_t nc_lock; /* lock on this entry */
int nc_hittime; /* N last time scored a hit */
+ char nc_nlen; /* - length of name */
+ char nc_name[0]; /* - segment name */
};
#ifdef _KERNEL
Index: kern/vfs_cache.c
===================================================================
RCS file: /cvsroot/src/sys/kern/vfs_cache.c,v
retrieving revision 1.120
diff -u -p -u -r1.120 vfs_cache.c
--- kern/vfs_cache.c 18 Mar 2017 22:36:56 -0000 1.120
+++ kern/vfs_cache.c 10 Sep 2019 23:20:48 -0000
@@ -94,13 +94,13 @@ __KERNEL_RCSID(0, "$NetBSD: vfs_cache.c,
* containing name.
*
* For simplicity (and economy of storage), names longer than
- * a maximum length of NCHNAMLEN are not cached; they occur
- * infrequently in any case, and are almost never of interest.
+ * a maximum length of NCHNAMLEN are stored in non-pooled storage.
*
* Upon reaching the last segment of a path, if the reference
* is for DELETE, or NOCACHE is set (rewrite), and the
* name is located in the cache, it will be dropped.
*/
+#define NCHNAMLEN 30
/*
* Cache entry lifetime:
@@ -589,7 +589,7 @@ cache_lookup(struct vnode *dvp, const ch
cpup = curcpu()->ci_data.cpu_nch;
mutex_enter(&cpup->cpu_lock);
- if (__predict_false(namelen > NCHNAMLEN)) {
+ if (__predict_false(namelen > USHRT_MAX)) {
SDT_PROBE(vfs, namecache, lookup, toolong, dvp,
name, namelen, 0, 0);
COUNT(cpup, ncs_long);
@@ -703,7 +703,7 @@ cache_lookup_raw(struct vnode *dvp, cons
cpup = curcpu()->ci_data.cpu_nch;
mutex_enter(&cpup->cpu_lock);
- if (__predict_false(namelen > NCHNAMLEN)) {
+ if (__predict_false(namelen > USHRT_MAX)) {
COUNT(cpup, ncs_long);
mutex_exit(&cpup->cpu_lock);
/* found nothing */
@@ -868,7 +868,7 @@ cache_enter(struct vnode *dvp, struct vn
/* First, check whether we can/should add a cache entry. */
if ((cnflags & MAKEENTRY) == 0 ||
- __predict_false(namelen > NCHNAMLEN || !doingcache)) {
+ __predict_false(namelen > USHRT_MAX || !doingcache)) {
SDT_PROBE(vfs, namecache, enter, toolong, vp, name, namelen,
0, 0);
return;
@@ -882,7 +882,11 @@ cache_enter(struct vnode *dvp, struct vn
mutex_exit(namecache_lock);
}
- ncp = pool_cache_get(namecache_cache, PR_WAITOK);
+ if (namelen > NCHNAMLEN) {
+ ncp = kmem_alloc(sizeof(*ncp) + namelen, KM_SLEEP);
+ cache_ctor(NULL, ncp, 0);
+ } else
+ ncp = pool_cache_get(namecache_cache, PR_WAITOK);
mutex_enter(namecache_lock);
numcache++;
@@ -919,7 +923,7 @@ cache_enter(struct vnode *dvp, struct vn
ncp->nc_vlist.le_prev = NULL;
ncp->nc_vlist.le_next = NULL;
}
- KASSERT(namelen <= NCHNAMLEN);
+ KASSERT(namelen <= USHRT_MAX);
ncp->nc_nlen = namelen;
memcpy(ncp->nc_name, name, (unsigned)ncp->nc_nlen);
TAILQ_INSERT_TAIL(&nclruhead, ncp, nc_lru);
@@ -970,7 +974,7 @@ nchinit(void)
int error;
TAILQ_INIT(&nclruhead);
- namecache_cache = pool_cache_init(sizeof(struct namecache),
+ namecache_cache = pool_cache_init(sizeof(struct namecache) + NCHNAMLEN,
coherency_unit, 0, 0, "ncache", NULL, IPL_NONE, cache_ctor,
cache_dtor, NULL);
KASSERT(namecache_cache != NULL);
@@ -1248,7 +1252,11 @@ cache_reclaim(void)
LIST_REMOVE(ncp, nc_hash);
ncp->nc_hash.le_prev = NULL;
}
- pool_cache_put(namecache_cache, ncp);
+ if (ncp->nc_nlen > NCHNAMLEN) {
+ cache_dtor(NULL, ncp);
+ kmem_free(ncp, sizeof(*ncp) + ncp->nc_nlen);
+ } else
+ pool_cache_put(namecache_cache, ncp);
ncp = next;
}
cache_unlock_cpus();
