From: Rich Felker <dalias@aerifal.cx>
Date: Wed, 16 Mar 2011 14:39:45 +0000 (-0400)
Subject: optimize file locking: avoid cache-polluting writes to global storage
X-Git-Tag: v0.7.1~13
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=4d9cc0b399b1d6a146cb45e64c74b7ee562de7a6;p=musl

optimize file locking: avoid cache-polluting writes to global storage
---

diff --git a/src/stdio/flockfile.c b/src/stdio/flockfile.c
index 1b6ef580..440a36a9 100644
--- a/src/stdio/flockfile.c
+++ b/src/stdio/flockfile.c
@@ -3,7 +3,9 @@
 
 void flockfile(FILE *f)
 {
-	pthread_self();
-	libc.lockfile = __lockfile;
+	if (!libc.lockfile) {
+		pthread_self();
+		libc.lockfile = __lockfile;
+	}
 	__lockfile(f);
 }
diff --git a/src/stdio/ftrylockfile.c b/src/stdio/ftrylockfile.c
index 725b66e7..1d0a1ff8 100644
--- a/src/stdio/ftrylockfile.c
+++ b/src/stdio/ftrylockfile.c
@@ -3,7 +3,7 @@
 
 int ftrylockfile(FILE *f)
 {
-	libc.lockfile = __lockfile;
+	if (!libc.lockfile) libc.lockfile = __lockfile;
 	if (f->owner && f->owner == pthread_self()->tid) {
 		if (f->lockcount == INT_MAX)
 			return -1;