Module Name: src
Committed By: ad
Date: Sun Mar 22 00:34:31 UTC 2020
Modified Files:
src/sys/kern [ad-namecache]: vfs_cache.c
Log Message:
- Fold the "doingcache" conditional into the max length conditional.
- Mark the tunables __read_mostly.
To generate a diff of this commit:
cvs rdiff -u -r1.126.2.14 -r1.126.2.15 src/sys/kern/vfs_cache.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/vfs_cache.c
diff -u src/sys/kern/vfs_cache.c:1.126.2.14 src/sys/kern/vfs_cache.c:1.126.2.15
--- src/sys/kern/vfs_cache.c:1.126.2.14 Sat Mar 21 22:00:55 2020
+++ src/sys/kern/vfs_cache.c Sun Mar 22 00:34:31 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: vfs_cache.c,v 1.126.2.14 2020/03/21 22:00:55 ad Exp $ */
+/* $NetBSD: vfs_cache.c,v 1.126.2.15 2020/03/22 00:34:31 ad Exp $ */
/*-
* Copyright (c) 2008, 2019, 2020 The NetBSD Foundation, Inc.
@@ -171,7 +171,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_cache.c,v 1.126.2.14 2020/03/21 22:00:55 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_cache.c,v 1.126.2.15 2020/03/22 00:34:31 ad Exp $");
#define __NAMECACHE_PRIVATE
#ifdef _KERNEL_OPT
@@ -235,10 +235,13 @@ struct nchstats nchstats __cacheline_ali
KPREEMPT_ENABLE(l); \
} while (/* CONSTCOND */ 0);
-/* Tunables */
-static const int cache_lru_maxdeact = 2; /* max # to deactivate */
-static const int cache_lru_maxscan = 64; /* max # to scan/reclaim */
-static int doingcache = 1; /* 1 => enable the cache */
+/*
+ * Tunables. cache_maxlen replaces the historical doingcache:
+ * set it zero to disable caching for debugging purposes.
+ */
+int cache_lru_maxdeact __read_mostly = 2; /* max # to deactivate */
+int cache_lru_maxscan __read_mostly = 64; /* max # to scan/reclaim */
+int cache_maxlen __read_mostly = USHRT_MAX; /* max name length to cache */
/* sysctl */
static struct sysctllog *cache_sysctllog;
@@ -515,11 +518,7 @@ cache_lookup(struct vnode *dvp, const ch
}
*vn_ret = NULL;
- if (__predict_false(!doingcache)) {
- return false;
- }
-
- if (__predict_false(namelen > USHRT_MAX)) {
+ if (__predict_false(namelen > cache_maxlen)) {
SDT_PROBE(vfs, namecache, lookup, toolong, dvp,
name, namelen, 0, 0);
COUNT(ncs_long);
@@ -644,7 +643,7 @@ cache_lookup_linked(struct vnode *dvp, c
*vn_ret = NULL;
/* If disabled, or file system doesn't support this, bail out. */
- if (__predict_false(!doingcache ||
+ if (__predict_false(cache_maxlen == 0 ||
(dvp->v_mount->mnt_iflag & IMNT_NCLOOKUP) == 0)) {
return false;
}
@@ -753,7 +752,7 @@ cache_revlookup(struct vnode *vp, struct
KASSERT(vp != NULL);
- if (!doingcache)
+ if (cache_maxlen == 0)
goto out;
rw_enter(&vi->vi_nc_listlock, RW_READER);
@@ -855,7 +854,7 @@ cache_enter(struct vnode *dvp, struct vn
/* First, check whether we can/should add a cache entry. */
if ((cnflags & MAKEENTRY) == 0 ||
- __predict_false(namelen > USHRT_MAX || !doingcache)) {
+ __predict_false(namelen > cache_maxlen)) {
SDT_PROBE(vfs, namecache, enter, toolong, vp, name, namelen,
0, 0);
return;
