Author: kib
Date: Sat Oct 16 09:44:31 2010
New Revision: 213916
URL: http://svn.freebsd.org/changeset/base/213916
Log:
Provide vfs.ncsizefactor instead of hard-coding namecache ratio.
Move debug.ncnegfactor to vfs.ncnegfactor [1].
Provide some descriptions for the namecache related sysctls [1].
Based on the submission by: Rogier R. Mulhuijzen <drwilco drwilco net> [1]
MFC after: 2 weeks
X-MFC-note: remove debug.ncnegfactor in HEAD after MFC
Modified:
head/sys/kern/vfs_cache.c
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Sat Oct 16 08:43:23 2010 (r213915)
+++ head/sys/kern/vfs_cache.c Sat Oct 16 09:44:31 2010 (r213916)
@@ -126,20 +126,27 @@ struct namecache {
static LIST_HEAD(nchashhead, namecache) *nchashtbl; /* Hash Table */
static TAILQ_HEAD(, namecache) ncneg; /* Hash Table */
static u_long nchash; /* size of hash table */
-SYSCTL_ULONG(_debug, OID_AUTO, nchash, CTLFLAG_RD, &nchash, 0, "");
+SYSCTL_ULONG(_debug, OID_AUTO, nchash, CTLFLAG_RD, &nchash, 0,
+ "Size of namecache hash table");
static u_long ncnegfactor = 16; /* ratio of negative entries */
+/* _debug sysctl left for backward compatibility */
SYSCTL_ULONG(_debug, OID_AUTO, ncnegfactor, CTLFLAG_RW, &ncnegfactor, 0, "");
-static u_long numneg; /* number of cache entries allocated */
-SYSCTL_ULONG(_debug, OID_AUTO, numneg, CTLFLAG_RD, &numneg, 0, "");
+SYSCTL_ULONG(_vfs, OID_AUTO, ncnegfactor, CTLFLAG_RW, &ncnegfactor, 0,
+ "Ratio of negative namecache entries");
+static u_long numneg; /* number of negative entries allocated
*/
+SYSCTL_ULONG(_debug, OID_AUTO, numneg, CTLFLAG_RD, &numneg, 0,
+ "Number of negative entries in namecache");
static u_long numcache; /* number of cache entries allocated */
-SYSCTL_ULONG(_debug, OID_AUTO, numcache, CTLFLAG_RD, &numcache, 0, "");
+SYSCTL_ULONG(_debug, OID_AUTO, numcache, CTLFLAG_RD, &numcache, 0,
+ "Number of namecache entries");
static u_long numcachehv; /* number of cache entries with vnodes
held */
-SYSCTL_ULONG(_debug, OID_AUTO, numcachehv, CTLFLAG_RD, &numcachehv, 0, "");
-#if 0
-static u_long numcachepl; /* number of cache purge for leaf
entries */
-SYSCTL_ULONG(_debug, OID_AUTO, numcachepl, CTLFLAG_RD, &numcachepl, 0, "");
-#endif
-struct nchstats nchstats; /* cache effectiveness statistics */
+SYSCTL_ULONG(_debug, OID_AUTO, numcachehv, CTLFLAG_RD, &numcachehv, 0,
+ "Number of namecache entries with vnodes held");
+static u_int ncsizefactor = 2;
+SYSCTL_UINT(_vfs, OID_AUTO, ncsizefactor, CTLFLAG_RW, &ncsizefactor, 0,
+ "Size factor for namecache");
+
+struct nchstats nchstats; /* cache effectiveness
statistics */
static struct rwlock cache_lock;
RW_SYSINIT(vfscache, &cache_lock, "Name Cache");
@@ -174,7 +181,8 @@ static uma_zone_t cache_zone_large;
} while (0)
static int doingcache = 1; /* 1 => enable the cache */
-SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0, "");
+SYSCTL_INT(_debug, OID_AUTO, vfscache, CTLFLAG_RW, &doingcache, 0,
+ "VFS namecache enabled");
/* Export size information to userland */
SYSCTL_INT(_debug_sizeof, OID_AUTO, namecache, CTLFLAG_RD, 0,
@@ -620,7 +628,7 @@ cache_enter(dvp, vp, cnp)
/*
* Avoid blowout in namecache entries.
*/
- if (numcache >= desiredvnodes * 2)
+ if (numcache >= desiredvnodes * ncsizefactor)
return;
flag = 0;
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