* [PATCH] cleancache: use __read_mostly for cleancache_enabled
@ 2011-05-29 20:38 ` Cesar Eduardo Barros
0 siblings, 0 replies; 4+ messages in thread
From: Cesar Eduardo Barros @ 2011-05-29 20:38 UTC (permalink / raw)
To: linux-mm
Cc: Minchan Kim, Jan Beulich, Andrew Morton, Andreas Dilger,
Dan Magenheimer, Jeremy Fitzhardinge, linux-kernel,
Cesar Eduardo Barros
The global variable cleancache_enabled is read often but written to
rarely. Use __read_mostly to prevent it being on the same cacheline as
another variable which is written to often, which would cause cacheline
bouncing.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
---
include/linux/cleancache.h | 2 +-
mm/cleancache.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/cleancache.h b/include/linux/cleancache.h
index 04ffb2e..83fffe8 100644
--- a/include/linux/cleancache.h
+++ b/include/linux/cleancache.h
@@ -42,7 +42,7 @@ extern void __cleancache_put_page(struct page *);
extern void __cleancache_flush_page(struct address_space *, struct page *);
extern void __cleancache_flush_inode(struct address_space *);
extern void __cleancache_flush_fs(struct super_block *);
-extern int cleancache_enabled;
+extern int cleancache_enabled __read_mostly;
#ifdef CONFIG_CLEANCACHE
static inline bool cleancache_fs_enabled(struct page *page)
diff --git a/mm/cleancache.c b/mm/cleancache.c
index bcaae4c..a3d7a22 100644
--- a/mm/cleancache.c
+++ b/mm/cleancache.c
@@ -24,7 +24,7 @@
* disabled), so is preferred to the slower alternative: a function
* call that checks a non-global.
*/
-int cleancache_enabled;
+int cleancache_enabled __read_mostly;
EXPORT_SYMBOL(cleancache_enabled);
/*
--
1.7.4.4
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] cleancache: use __read_mostly for cleancache_enabled
@ 2011-05-29 20:38 ` Cesar Eduardo Barros
0 siblings, 0 replies; 4+ messages in thread
From: Cesar Eduardo Barros @ 2011-05-29 20:38 UTC (permalink / raw)
To: linux-mm
Cc: Minchan Kim, Jan Beulich, Andrew Morton, Andreas Dilger,
Dan Magenheimer, Jeremy Fitzhardinge, linux-kernel,
Cesar Eduardo Barros
The global variable cleancache_enabled is read often but written to
rarely. Use __read_mostly to prevent it being on the same cacheline as
another variable which is written to often, which would cause cacheline
bouncing.
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
---
include/linux/cleancache.h | 2 +-
mm/cleancache.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/cleancache.h b/include/linux/cleancache.h
index 04ffb2e..83fffe8 100644
--- a/include/linux/cleancache.h
+++ b/include/linux/cleancache.h
@@ -42,7 +42,7 @@ extern void __cleancache_put_page(struct page *);
extern void __cleancache_flush_page(struct address_space *, struct page *);
extern void __cleancache_flush_inode(struct address_space *);
extern void __cleancache_flush_fs(struct super_block *);
-extern int cleancache_enabled;
+extern int cleancache_enabled __read_mostly;
#ifdef CONFIG_CLEANCACHE
static inline bool cleancache_fs_enabled(struct page *page)
diff --git a/mm/cleancache.c b/mm/cleancache.c
index bcaae4c..a3d7a22 100644
--- a/mm/cleancache.c
+++ b/mm/cleancache.c
@@ -24,7 +24,7 @@
* disabled), so is preferred to the slower alternative: a function
* call that checks a non-global.
*/
-int cleancache_enabled;
+int cleancache_enabled __read_mostly;
EXPORT_SYMBOL(cleancache_enabled);
/*
--
1.7.4.4
--
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] cleancache: use __read_mostly for cleancache_enabled
2011-05-29 20:38 ` Cesar Eduardo Barros
@ 2011-05-30 0:35 ` Minchan Kim
-1 siblings, 0 replies; 4+ messages in thread
From: Minchan Kim @ 2011-05-30 0:35 UTC (permalink / raw)
To: Cesar Eduardo Barros
Cc: linux-mm, Jan Beulich, Andrew Morton, Andreas Dilger,
Dan Magenheimer, Jeremy Fitzhardinge, linux-kernel
On Mon, May 30, 2011 at 5:38 AM, Cesar Eduardo Barros <cesarb@cesarb.net> wrote:
> The global variable cleancache_enabled is read often but written to
> rarely. Use __read_mostly to prevent it being on the same cacheline as
> another variable which is written to often, which would cause cacheline
> bouncing.
>
> Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
--
Kind regards,
Minchan Kim
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] cleancache: use __read_mostly for cleancache_enabled
@ 2011-05-30 0:35 ` Minchan Kim
0 siblings, 0 replies; 4+ messages in thread
From: Minchan Kim @ 2011-05-30 0:35 UTC (permalink / raw)
To: Cesar Eduardo Barros
Cc: linux-mm, Jan Beulich, Andrew Morton, Andreas Dilger,
Dan Magenheimer, Jeremy Fitzhardinge, linux-kernel
On Mon, May 30, 2011 at 5:38 AM, Cesar Eduardo Barros <cesarb@cesarb.net> wrote:
> The global variable cleancache_enabled is read often but written to
> rarely. Use __read_mostly to prevent it being on the same cacheline as
> another variable which is written to often, which would cause cacheline
> bouncing.
>
> Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
--
Kind regards,
Minchan Kim
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2011-05-30 0:35 UTC | newest]
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2011-05-29 20:38 [PATCH] cleancache: use __read_mostly for cleancache_enabled Cesar Eduardo Barros
2011-05-29 20:38 ` Cesar Eduardo Barros
2011-05-30 0:35 ` Minchan Kim
2011-05-30 0:35 ` Minchan Kim
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