* [PATCH] avoid reading errno repeatedly
@ 2017-03-17 1:57 Eric Wong
0 siblings, 0 replies; only message in thread
From: Eric Wong @ 2017-03-17 1:57 UTC (permalink / raw)
To: raindrops-public
errno is in the thread-specific section and it is slightly
cheaper to read it once rather than twice. Recent versions
of mainline Ruby itself follows the same pattern.
---
ext/raindrops/raindrops.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/ext/raindrops/raindrops.c b/ext/raindrops/raindrops.c
index 390b8b8..9090839 100644
--- a/ext/raindrops/raindrops.c
+++ b/ext/raindrops/raindrops.c
@@ -117,7 +117,9 @@ retry:
r->drops = mmap(NULL, tmp,
PROT_READ|PROT_WRITE, MAP_ANON|MAP_SHARED, -1, 0);
if (r->drops == MAP_FAILED) {
- if ((errno == EAGAIN || errno == ENOMEM) && tries-- > 0) {
+ int err = errno;
+
+ if ((err == EAGAIN || err == ENOMEM) && tries-- > 0) {
rb_gc();
goto retry;
}
@@ -153,7 +155,9 @@ static void resize(struct raindrops *r, size_t new_rd_size)
rv = mremap(old_address, old_size, new_size, MREMAP_MAYMOVE);
if (rv == MAP_FAILED) {
- if (errno == EAGAIN || errno == ENOMEM) {
+ int err = errno;
+
+ if (err == EAGAIN || err == ENOMEM) {
rb_gc();
rv = mremap(old_address, old_size, new_size, 0);
}
--
EW
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