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lockf: skip locking the graph if not necessary (common case)

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Tested by:      pho
This commit is contained in:
Mateusz Guzik 2018-04-23 07:54:02 +00:00
parent 717df0b0e8
commit 63286976b5
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=332881
1 changed files with 9 additions and 6 deletions
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15
sys/kern/kern_lockf.c
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@ -1053,6 +1053,12 @@ lf_add_incoming(struct lockf *state, struct lockf_entry *lock)
struct lockf_entry *overlap;
int error;
sx_assert(&state->ls_lock, SX_XLOCKED);
if (LIST_EMPTY(&state->ls_pending))
return (0);
error = 0;
sx_xlock(&lf_owner_graph_lock);
LIST_FOREACH(overlap, &state->ls_pending, lf_link) {
if (!lf_blocks(lock, overlap))
continue;
@ -1070,10 +1076,11 @@ lf_add_incoming(struct lockf *state, struct lockf_entry *lock)
*/
if (error) {
lf_remove_incoming(lock);
return (error);
break;
}
}
return (0);
sx_xunlock(&lf_owner_graph_lock);
return (error);
}
/*
@ -1509,9 +1516,7 @@ lf_setlock(struct lockf *state, struct lockf_entry *lock, struct vnode *vp,
* edges from any currently pending lock that the new lock
* would block.
*/
sx_xlock(&lf_owner_graph_lock);
error = lf_add_incoming(state, lock);
sx_xunlock(&lf_owner_graph_lock);
if (error) {
#ifdef LOCKF_DEBUG
if (lockf_debug & 1)
@ -1840,9 +1845,7 @@ lf_split(struct lockf *state, struct lockf_entry *lock1,
splitlock->lf_start = lock2->lf_end + 1;
LIST_INIT(&splitlock->lf_outedges);
LIST_INIT(&splitlock->lf_inedges);
sx_xlock(&lf_owner_graph_lock);
lf_add_incoming(state, splitlock);
sx_xunlock(&lf_owner_graph_lock);
lf_set_end(state, lock1, lock2->lf_start - 1, granted);