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authorRich Felker <dalias@aerifal.cx>2011-03-24 23:16:52 -0400
committerRich Felker <dalias@aerifal.cx>2011-03-24 23:16:52 -0400
commita37452430f93700aeb122d693959ad79d8e43ada (patch)
tree6ed8879bddb17c2b0db8c8bbd4778e11912f0767 /src/stdio/__lockfile.c
parentd8dc2faf1033e134e3a8f39bdf15c065f4d234be (diff)
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simplify and optimize FILE lock handling
Diffstat (limited to 'src/stdio/__lockfile.c')
-rw-r--r--src/stdio/__lockfile.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/src/stdio/__lockfile.c b/src/stdio/__lockfile.c
index e4320f05..93c94867 100644
--- a/src/stdio/__lockfile.c
+++ b/src/stdio/__lockfile.c
@@ -3,17 +3,18 @@
void __lockfile(FILE *f)
{
- int spins;
- if (f->owner < 0) return;
- if (f->owner && f->owner == __pthread_self()->tid) {
+ int spins=100000;
+ int tid;
+
+ if (f->lock < 0) return;
+ tid = __pthread_self()->tid;
+ if (f->lock == tid) {
while (f->lockcount == INT_MAX);
f->lockcount++;
return;
}
- spins = 100000;
- while (a_swap(&f->lock, 1))
+ while (f->lock || a_cas(&f->lock, 0, tid))
if (spins) spins--, a_spin();
else syscall(SYS_sched_yield);
- f->owner = __pthread_self()->tid;
f->lockcount = 1;
}