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cache: fold branch prediction into cache_ncp_canuse

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This commit is contained in:
Mateusz Guzik 2020-10-24 01:13:47 +00:00
parent c13d7d1f98
commit 1d44405690
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=366986
1 changed files with 13 additions and 12 deletions
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25
sys/kern/vfs_cache.c
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@ -233,13 +233,14 @@ 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)
{
atomic_thread_fence_acq();
return ((atomic_load_char(&ncp->nc_flag) & (NCF_INVALID | NCF_WIP)) == 0);
}
#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); \
})
/*
* Name caching works as follows:
@ -1056,7 +1057,7 @@ cache_neg_promote_cond(struct vnode *dvp, struct componentname *cnp,
goto out_abort;
}
if (__predict_false(!cache_ncp_canuse(ncp))) {
if (!cache_ncp_canuse(ncp)) {
goto out_abort;
}
@ -1834,7 +1835,7 @@ cache_lookup(struct vnode *dvp, struct vnode **vpp, struct componentname *cnp,
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 namecache *ncp, uint32_t hash)
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));
}