The patch titled
Subject: kernel/cred.c: remove unnecessary kdebug atomic reads
has been added to the -mm tree. Its filename is
cred-remove-unnecessary-kdebug-atomic-reads.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/cred-remove-unnecessary-kdebug-atomic-reads.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/cred-remove-unnecessary-kdebug-atomic-reads.patch
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------------------------------------------------------
From: Joe Perches <joe@xxxxxxxxxxx>
Subject: kernel/cred.c: remove unnecessary kdebug atomic reads
Commit e0e817392b9a ("CRED: Add some configurable debugging [try #6]")
added the kdebug mechanism to this file back in 2009.
The kdebug macro calls no_printk which always evaluates arguments.
Most of the kdebug uses have an unnecessary call of
atomic_read(&cred->usage)
Make the kdebug macro do nothing by defining it with
do { if (0) no_printk(...); } while (0)
when not enabled.
$ size kernel/cred.o* (defconfig x86-64)
text data bss dec hex filename
2748 336 8 3092 c14 kernel/cred.o.new
2788 336 8 3132 c3c kernel/cred.o.old
Miscellanea:
o Neaten the #define kdebug macros while there
Signed-off-by: Joe Perches <joe@xxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: James Morris <jmorris@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/cred.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff -puN kernel/cred.c~cred-remove-unnecessary-kdebug-atomic-reads kernel/cred.c
--- a/kernel/cred.c~cred-remove-unnecessary-kdebug-atomic-reads
+++ a/kernel/cred.c
@@ -20,11 +20,16 @@
#include <linux/cn_proc.h>
#if 0
-#define kdebug(FMT, ...) \
- printk("[%-5.5s%5u] "FMT"\n", current->comm, current->pid ,##__VA_ARGS__)
+#define kdebug(FMT, ...) \
+ printk("[%-5.5s%5u] " FMT "\n", \
+ current->comm, current->pid, ##__VA_ARGS__)
#else
-#define kdebug(FMT, ...) \
- no_printk("[%-5.5s%5u] "FMT"\n", current->comm, current->pid ,##__VA_ARGS__)
+#define kdebug(FMT, ...) \
+do { \
+ if (0) \
+ no_printk("[%-5.5s%5u] " FMT "\n", \
+ current->comm, current->pid, ##__VA_ARGS__); \
+} while (0)
#endif
static struct kmem_cache *cred_jar;
_
Patches currently in -mm which might be from joe@xxxxxxxxxxx are
ocfs2-neaten-do_error-ocfs2_error-and-ocfs2_abort.patch
cred-remove-unnecessary-kdebug-atomic-reads.patch
maintainers-credits-mark-maxraid-as-orphan-move-anil-ravindranath-to-credits.patch
checkpatch-warn-on-bare-sha-1-commit-ids-in-commit-logs.patch
checkpatch-add-warning-on-bug-bug_on-use.patch
checkpatch-improve-suspect_code_indent-test.patch
checkpatch-allow-longer-declaration-macros.patch
checkpatch-add-some-foo_destroy-functions-to-needless_if-tests.patch
checkpatch-report-the-right-line-when-using-emacs-and-file.patch
checkpatch-always-check-block-comment-styles.patch
checkpatch-make-strict-the-default-for-drivers-staging-files-and-patches.patch
checkpatch-emit-an-error-on-formats-with-0x%decimal.patch
checkpatch-avoid-some-commit-message-long-line-warnings.patch
checkpatch-add-__pmem-to-sparse-annotations.patch
fs-seq_file-convert-int-seq_vprint-seq_printf-etc-returns-to-void.patch
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