From: Eric Wong <e@80x24.org>
To: mwrap-perl@80x24.org
Subject: [PATCH] mymalloc: use ftruncate(2) when creating a sparse file
Date: Tue, 3 Jan 2023 07:25:24 +0000 [thread overview]
Message-ID: <20230103072524.849720-1-e@80x24.org> (raw)
Unlike pwrite(2), it won't dirty the last page, and it's fewer
arguments so argument passing is simpler.
---
mymalloc.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mymalloc.h b/mymalloc.h
index e781b43..eda669f 100644
--- a/mymalloc.h
+++ b/mymalloc.h
@@ -69,9 +69,9 @@ static void *my_mmap(size_t size)
if (fd < 0) {
flags |= MAP_ANONYMOUS;
} else {
- ssize_t w = pwrite(fd, "", 1, size - 1); /* sparse file */
+ int t = ftruncate(fd, size); /* sparse file */
- if (w <= 0) { /* 0 may be ENOSPC */
+ if (t < 0) {
flags |= MAP_ANONYMOUS;
close(fd);
fd = -1;
reply other threads:[~2023-01-03 7:25 UTC|newest]
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