Author: mjg
Date: Sun Jan 19 05:37:27 2020
New Revision: 356880
URL: https://svnweb.freebsd.org/changeset/base/356880
Log:
cache: convert numcachehv to counter(9) on 64-bit platforms
Modified:
head/sys/kern/vfs_cache.c
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Sun Jan 19 05:36:45 2020 (r356879)
+++ head/sys/kern/vfs_cache.c Sun Jan 19 05:37:27 2020 (r356880)
@@ -205,7 +205,6 @@ SYSCTL_ULONG(_vfs, OID_AUTO, ncnegfactor, CTLFLAG_RW,
"Ratio of negative namecache entries");
static u_long __exclusive_cache_line numneg; /* number of negative entries
allocated */
static u_long __exclusive_cache_line numcache;/* number of cache entries
allocated */
-static u_long __exclusive_cache_line numcachehv;/* number of cache entries
with vnodes held */
u_int ncsizefactor = 2;
SYSCTL_UINT(_vfs, OID_AUTO, ncsizefactor, CTLFLAG_RW, &ncsizefactor, 0,
"Size factor for namecache");
@@ -341,6 +340,16 @@ SYSCTL_INT(_debug_sizeof, OID_AUTO, namecache, CTLFLAG
sizeof(struct namecache), "sizeof(struct namecache)");
/*
+ * Use counter(9) for numcachehv if the machine is 64-bit.
+ *
+ * Stick to an atomic for the rest since there is no long-sized equivalent and
+ * 64-bit size is both way more than needed and a pessimization.
+ */
+#ifdef __LP64__
+#define CACHE_NUMCACHEHV_U64
+#endif
+
+/*
* The new name cache statistics
*/
static SYSCTL_NODE(_vfs, OID_AUTO, cache, CTLFLAG_RW, 0,
@@ -352,7 +361,12 @@ static SYSCTL_NODE(_vfs, OID_AUTO, cache, CTLFLAG_RW,
SYSCTL_COUNTER_U64(_vfs_cache, OID_AUTO, name, CTLFLAG_RD, &name,
descr);
STATNODE_ULONG(numneg, "Number of negative cache entries");
STATNODE_ULONG(numcache, "Number of cache entries");
+#ifdef CACHE_NUMCACHEHV_U64
+STATNODE_COUNTER(numcachehv, "Number of namecache entries with vnodes held");
+#else
+static u_long __exclusive_cache_line numcachehv;/* number of cache entries
with vnodes held */
STATNODE_ULONG(numcachehv, "Number of namecache entries with vnodes held");
+#endif
STATNODE_COUNTER(numcalls, "Number of cache lookups");
STATNODE_COUNTER(dothits, "Number of '.' hits");
STATNODE_COUNTER(dotdothits, "Number of '..' hits");
@@ -393,6 +407,36 @@ static int vn_fullpath1(struct thread *td, struct vnod
static MALLOC_DEFINE(M_VFSCACHE, "vfscache", "VFS name cache entries");
+#ifdef CACHE_NUMCACHEHV_U64
+static void
+cache_numcachehv_inc(void)
+{
+
+ counter_u64_add_protected(numcachehv, 1);
+}
+
+static void
+cache_numcachehv_dec(void)
+{
+
+ counter_u64_add_protected(numcachehv, -1);
+}
+#else
+static void
+cache_numcachehv_inc(void)
+{
+
+ atomic_add_long(&numcachehv, 1);
+}
+
+static void
+cache_numcachehv_dec(void)
+{
+
+ atomic_subtract_long(&numcachehv, 1);
+}
+#endif
+
static int cache_yield;
SYSCTL_INT(_vfs_cache, OID_AUTO, yield, CTLFLAG_RD, &cache_yield, 0,
"Number of times cache called yield");
@@ -873,7 +917,7 @@ cache_zap_locked(struct namecache *ncp, bool neg_locke
LIST_REMOVE(ncp, nc_src);
if (LIST_EMPTY(&ncp->nc_dvp->v_cache_src)) {
ncp->nc_flag |= NCF_DVDROP;
- atomic_subtract_rel_long(&numcachehv, 1);
+ cache_numcachehv_dec();
}
}
atomic_subtract_rel_long(&numcache, 1);
@@ -1742,7 +1786,7 @@ cache_enter_time(struct vnode *dvp, struct vnode *vp,
held_dvp = false;
if (LIST_EMPTY(&dvp->v_cache_src) && flag != NCF_ISDOTDOT) {
vhold(dvp);
- atomic_add_long(&numcachehv, 1);
+ cache_numcachehv_inc();
held_dvp = true;
}
@@ -1837,7 +1881,7 @@ cache_enter_time(struct vnode *dvp, struct vnode *vp,
if (LIST_EMPTY(&dvp->v_cache_src)) {
if (!held_dvp) {
vhold(dvp);
- atomic_add_long(&numcachehv, 1);
+ cache_numcachehv_inc();
}
} else {
if (held_dvp) {
@@ -1848,7 +1892,7 @@ cache_enter_time(struct vnode *dvp, struct vnode *vp,
* this from changing.
*/
vdrop(dvp);
- atomic_subtract_long(&numcachehv, 1);
+ cache_numcachehv_dec();
}
}
LIST_INSERT_HEAD(&dvp->v_cache_src, ncp, nc_src);
@@ -1886,7 +1930,7 @@ out_unlock_free:
cache_free(ncp);
if (held_dvp) {
vdrop(dvp);
- atomic_subtract_long(&numcachehv, 1);
+ cache_numcachehv_dec();
}
return;
}
@@ -1957,6 +2001,9 @@ nchinit(void *dummy __unused)
mtx_init(&ncneg_shrink_lock, "ncnegs", NULL, MTX_DEF);
+#ifdef CACHE_NUMCACHEHV_U64
+ numcachehv = counter_u64_alloc(M_WAITOK);
+#endif
numcalls = counter_u64_alloc(M_WAITOK);
dothits = counter_u64_alloc(M_WAITOK);
dotdothits = counter_u64_alloc(M_WAITOK);
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