Author: mjg
Date: Sun Sep 4 08:55:15 2016
New Revision: 305378
URL: https://svnweb.freebsd.org/changeset/base/305378
Log:
cache: put all negative entry management code into dedicated functions
Reviewed by: kib
MFC after: 1 week
Modified:
head/sys/kern/vfs_cache.c
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Sun Sep 4 08:53:58 2016 (r305377)
+++ head/sys/kern/vfs_cache.c Sun Sep 4 08:55:15 2016 (r305378)
@@ -433,6 +433,50 @@ SYSCTL_PROC(_debug_hashstat, OID_AUTO, n
#endif
/*
+ * Negative entries management
+ */
+static void
+cache_negative_hit(struct namecache *ncp)
+{
+
+ rw_assert(&cache_lock, RA_WLOCKED);
+ TAILQ_REMOVE(&ncneg, ncp, nc_dst);
+ TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst);
+}
+
+static void
+cache_negative_insert(struct namecache *ncp)
+{
+
+ rw_assert(&cache_lock, RA_WLOCKED);
+ MPASS(ncp->nc_vp == NULL);
+ TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst);
+ numneg++;
+}
+
+static void
+cache_negative_remove(struct namecache *ncp)
+{
+
+ rw_assert(&cache_lock, RA_WLOCKED);
+ MPASS(ncp->nc_vp == NULL);
+ TAILQ_REMOVE(&ncneg, ncp, nc_dst);
+ numneg--;
+}
+
+static void
+cache_negative_zap_one(void)
+{
+ struct namecache *ncp;
+
+ rw_assert(&cache_lock, RA_WLOCKED);
+ ncp = TAILQ_FIRST(&ncneg);
+ KASSERT(ncp->nc_vp == NULL, ("ncp %p vp %p on ncneg",
+ ncp, ncp->nc_vp));
+ cache_zap(ncp);
+}
+
+/*
* cache_zap():
*
* Removes a namecache entry from cache, whether it contains an actual
@@ -469,8 +513,7 @@ cache_zap(struct namecache *ncp)
if (ncp == ncp->nc_vp->v_cache_dd)
ncp->nc_vp->v_cache_dd = NULL;
} else {
- TAILQ_REMOVE(&ncneg, ncp, nc_dst);
- numneg--;
+ cache_negative_remove(ncp);
}
numcache--;
cache_free(ncp);
@@ -640,14 +683,7 @@ negative_success:
if (!wlocked && !CACHE_UPGRADE_LOCK())
goto wlock;
counter_u64_add(numneghits, 1);
- /*
- * We found a "negative" match, so we shift it to the end of
- * the "negative" cache entries queue to satisfy LRU. Also,
- * check to see if the entry is a whiteout; indicate this to
- * the componentname, if so.
- */
- TAILQ_REMOVE(&ncneg, ncp, nc_dst);
- TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst);
+ cache_negative_hit(ncp);
if (ncp->nc_flag & NCF_WHITE)
cnp->cn_flags |= ISWHITEOUT;
SDT_PROBE2(vfs, namecache, lookup, hit__negative, dvp,
@@ -759,15 +795,13 @@ cache_enter_time(struct vnode *dvp, stru
TAILQ_REMOVE(&ncp->nc_vp->v_cache_dst,
ncp, nc_dst);
} else {
- TAILQ_REMOVE(&ncneg, ncp, nc_dst);
- numneg--;
+ cache_negative_remove(ncp);
}
if (vp != NULL) {
TAILQ_INSERT_HEAD(&vp->v_cache_dst,
ncp, nc_dst);
} else {
- TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst);
- numneg++;
+ cache_negative_insert(ncp);
}
ncp->nc_vp = vp;
CACHE_WUNLOCK();
@@ -893,17 +927,12 @@ cache_enter_time(struct vnode *dvp, stru
} else {
if (cnp->cn_flags & ISWHITEOUT)
ncp->nc_flag |= NCF_WHITE;
- TAILQ_INSERT_TAIL(&ncneg, ncp, nc_dst);
- numneg++;
+ cache_negative_insert(ncp);
SDT_PROBE2(vfs, namecache, enter_negative, done, dvp,
nc_get_name(ncp));
}
- if (numneg * ncnegfactor > numcache) {
- ncp = TAILQ_FIRST(&ncneg);
- KASSERT(ncp->nc_vp == NULL, ("ncp %p vp %p on ncneg",
- ncp, ncp->nc_vp));
- cache_zap(ncp);
- }
+ if (numneg * ncnegfactor > numcache)
+ cache_negative_zap_one();
CACHE_WUNLOCK();
}
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