Commit-ID: 3ea2f2b96f9e636f49eb10962e96db3e19cab157
Gitweb: http://git.kernel.org/tip/3ea2f2b96f9e636f49eb10962e96db3e19cab157
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Wed, 16 Oct 2013 22:10:04 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 29 Oct 2013 12:02:52 +0100
perf: Do not waste PAGE_SIZE bytes for ALIGN(8) in perf_event_mmap_event()
perf_event_mmap_event() does kzalloc(PATH_MAX + sizeof(u64)) to
ensure we can align the size later. However this means that we
actually allocate PAGE_SIZE * 2 buffer, seems too much.
Change this code to allocate PATH_MAX==PAGE_SIZE bytes, but tell
d_path() to not use the last sizeof(u64) bytes.
Note: it is not clear why do we need __GFP_ZERO, see the next patch.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20131016201004.GC23214@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/events/core.c | 15 ++++++++-------
1 file changed, 8 insertions(+), 7 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 3ea5605..b409e75 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -5113,17 +5113,18 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
if (file) {
struct inode *inode;
dev_t dev;
- /*
- * d_path works from the end of the rb backwards, so we
- * need to add enough zero bytes after the string to handle
- * the 64bit alignment we do later.
- */
- buf = kzalloc(PATH_MAX + sizeof(u64), GFP_KERNEL);
+
+ buf = kzalloc(PATH_MAX, GFP_KERNEL);
if (!buf) {
name = strncpy(tmp, "//enomem", sizeof(tmp));
goto got_name;
}
- name = d_path(&file->f_path, buf, PATH_MAX);
+ /*
+ * d_path() works from the end of the rb backwards, so we
+ * need to add enough zero bytes after the string to handle
+ * the 64bit alignment we do later.
+ */
+ name = d_path(&file->f_path, buf, PATH_MAX - sizeof(u64));
if (IS_ERR(name)) {
name = strncpy(tmp, "//toolong", sizeof(tmp));
goto got_name;
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|