Author: mjg
Date: Sat Oct 24 01:13:47 2020
New Revision: 366986
URL: https://svnweb.freebsd.org/changeset/base/366986
Log:
cache: fold branch prediction into cache_ncp_canuse
Modified:
head/sys/kern/vfs_cache.c
Modified: head/sys/kern/vfs_cache.c
==============================================================================
--- head/sys/kern/vfs_cache.c Sat Oct 24 01:13:16 2020 (r366985)
+++ head/sys/kern/vfs_cache.c Sat Oct 24 01:13:47 2020 (r366986)
@@ -233,14 +233,15 @@ cache_ncp_invalidate(struct namecache *ncp)
* All places which elide locks are supposed to call this after they are
* done with reading from an entry.
*/
-static bool
-cache_ncp_canuse(struct namecache *ncp)
-{
+#define cache_ncp_canuse(ncp) ({ \
+ struct namecache *_ncp = (ncp); \
+ u_char _nc_flag; \
+ \
+ atomic_thread_fence_acq(); \
+ _nc_flag = atomic_load_char(&_ncp->nc_flag); \
+ __predict_true((_nc_flag & (NCF_INVALID | NCF_WIP)) == 0); \
+})
- atomic_thread_fence_acq();
- return ((atomic_load_char(&ncp->nc_flag) & (NCF_INVALID | NCF_WIP)) ==
0);
-}
-
/*
* Name caching works as follows:
*
@@ -1056,7 +1057,7 @@ cache_neg_promote_cond(struct vnode *dvp, struct compo
goto out_abort;
}
- if (__predict_false(!cache_ncp_canuse(ncp))) {
+ if (!cache_ncp_canuse(ncp)) {
goto out_abort;
}
@@ -1834,7 +1835,7 @@ negative_success:
cache_out_ts(ncp, tsp, ticksp);
whiteout = (ncp->nc_flag & NCF_WHITE);
neg_promote = cache_neg_hit_prep(ncp);
- if (__predict_false(!cache_ncp_canuse(ncp))) {
+ if (!cache_ncp_canuse(ncp)) {
cache_neg_hit_abort(ncp);
vfs_smr_exit();
goto out_fallback;
@@ -4008,7 +4009,7 @@ cache_fplookup_dotdot(struct cache_fpl *fpl)
fpl->tvp = ncp->nc_dvp;
}
- if (__predict_false(!cache_ncp_canuse(ncp))) {
+ if (!cache_ncp_canuse(ncp)) {
return (cache_fpl_aborted(fpl));
}
@@ -4041,7 +4042,7 @@ cache_fplookup_neg(struct cache_fpl *fpl, struct namec
return (cache_fpl_partial(fpl));
}
neg_promote = cache_neg_hit_prep(ncp);
- if (__predict_false(!cache_ncp_canuse(ncp))) {
+ if (!cache_ncp_canuse(ncp)) {
cache_neg_hit_abort(ncp);
return (cache_fpl_partial(fpl));
}
@@ -4096,7 +4097,7 @@ cache_fplookup_next(struct cache_fpl *fpl)
return (cache_fplookup_neg(fpl, ncp, hash));
}
- if (__predict_false(!cache_ncp_canuse(ncp))) {
+ if (!cache_ncp_canuse(ncp)) {
return (cache_fpl_partial(fpl));
}
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