[PATCH] mm: compaction: cache if a pageblock was scanned and no pages were isolated -fix

[PATCH] mm: compaction: cache if a pageblock was scanned and no pages were isolated -fix

[Mel Gorman]

Fengguang Wu reported the following

tree:   git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git since-3.5
head:   2f641f902ca76711e47e8d3b18004f0e46ca3d9b
commit: 7faeb2a39c789f1bac69014cc468677a60b73395 [184/186] mm:
compaction: cache if a pageblock was scanned and no pages were isolated
config: i386-randconfig-b083 (attached as .config)

All error/warnings:

mm/compaction.c: In function 'isolation_suitable':
mm/compaction.c:60:2: error: implicit declaration of function 'get_pageblock_skip' [-Werror=implicit-function-declaration]
mm/compaction.c: In function 'reset_isolation_suitable':
mm/compaction.c:94:3: error: implicit declaration of function 'clear_pageblock_skip' [-Werror=implicit-function-declaration]
mm/compaction.c: In function 'update_pageblock_skip':
mm/compaction.c:108:3: error: implicit declaration of function 'set_pageblock_skip' [-Werror=implicit-function-declaration]
mm/compaction.c: At top level:
mm/compaction.c:68:13: warning: 'reset_isolation_suitable' defined but not used [-Wunused-function]
mm/compaction.c:177:13: warning: 'compact_capture_page' defined but not used [-Wunused-function]
cc1: some warnings being treated as errors

Michal Hocko suggested implementing !CONFIG_COMPACTION versions of these
functions but that still leaves the dead version of
reset_isolation_suitable in the !CONFIG_COMPACTION && CONFIG_CMA case.
Create !CONFIG_COMPACTION versions of isolation_suitable() and
update_pageblock_skip() instead.

This is a fix for
mm-compaction-cache-if-a-pageblock-was-scanned-and-no-pages-were-isolated.patch

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 mm/compaction.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/mm/compaction.c b/mm/compaction.c
index 5ffe9a5..fb07abb 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -50,6 +50,7 @@ static inline bool migrate_async_suitable(int migratetype)
 	return is_migrate_cma(migratetype) || migratetype = MIGRATE_MOVABLE;
 }
 
+#ifdef CONFIG_COMPACTION
 /* Returns true if the pageblock should be scanned for pages to isolate. */
 static inline bool isolation_suitable(struct compact_control *cc,
 					struct page *page)
@@ -107,6 +108,17 @@ static void update_pageblock_skip(struct page *page, unsigned long nr_isolated)
 	if (!nr_isolated)
 		set_pageblock_skip(page);
 }
+#else
+static inline bool isolation_suitable(struct compact_control *cc,
+					struct page *page)
+{
+	return true;
+}
+
+static void update_pageblock_skip(struct page *page, unsigned long nr_isolated)
+{
+}
+#endif /* CONFIG_COMPACTION */
 
 static inline bool should_release_lock(spinlock_t *lock)
 {

Re: [PATCH] mm: compaction: cache if a pageblock was scanned and no pages were isolated -fix

[Michal Hocko]

On Wed 26-09-12 10:10:45, Mel Gorman wrote:
> Fengguang Wu reported the following
> 
> tree:   git://git.kernel.org/pub/scm/linux/kernel/git/mhocko/mm.git since-3.5
> head:   2f641f902ca76711e47e8d3b18004f0e46ca3d9b
> commit: 7faeb2a39c789f1bac69014cc468677a60b73395 [184/186] mm:
> compaction: cache if a pageblock was scanned and no pages were isolated
> config: i386-randconfig-b083 (attached as .config)
> 
> All error/warnings:
> 
> mm/compaction.c: In function 'isolation_suitable':
> mm/compaction.c:60:2: error: implicit declaration of function 'get_pageblock_skip' [-Werror=implicit-function-declaration]
> mm/compaction.c: In function 'reset_isolation_suitable':
> mm/compaction.c:94:3: error: implicit declaration of function 'clear_pageblock_skip' [-Werror=implicit-function-declaration]
> mm/compaction.c: In function 'update_pageblock_skip':
> mm/compaction.c:108:3: error: implicit declaration of function 'set_pageblock_skip' [-Werror=implicit-function-declaration]
> mm/compaction.c: At top level:
> mm/compaction.c:68:13: warning: 'reset_isolation_suitable' defined but not used [-Wunused-function]
> mm/compaction.c:177:13: warning: 'compact_capture_page' defined but not used [-Wunused-function]
> cc1: some warnings being treated as errors
> 
> Michal Hocko suggested implementing !CONFIG_COMPACTION versions of these
> functions but that still leaves the dead version of
> reset_isolation_suitable in the !CONFIG_COMPACTION && CONFIG_CMA case.
> Create !CONFIG_COMPACTION versions of isolation_suitable() and
> update_pageblock_skip() instead.

yes this makes more sense.
Thanks!

> 
> This is a fix for
> mm-compaction-cache-if-a-pageblock-was-scanned-and-no-pages-were-isolated.patch
> 
> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
> ---
>  mm/compaction.c |   12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 5ffe9a5..fb07abb 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -50,6 +50,7 @@ static inline bool migrate_async_suitable(int migratetype)
>  	return is_migrate_cma(migratetype) || migratetype = MIGRATE_MOVABLE;
>  }
>  
> +#ifdef CONFIG_COMPACTION
>  /* Returns true if the pageblock should be scanned for pages to isolate. */
>  static inline bool isolation_suitable(struct compact_control *cc,
>  					struct page *page)
> @@ -107,6 +108,17 @@ static void update_pageblock_skip(struct page *page, unsigned long nr_isolated)
>  	if (!nr_isolated)
>  		set_pageblock_skip(page);
>  }
> +#else
> +static inline bool isolation_suitable(struct compact_control *cc,
> +					struct page *page)
> +{
> +	return true;
> +}
> +
> +static void update_pageblock_skip(struct page *page, unsigned long nr_isolated)
> +{
> +}
> +#endif /* CONFIG_COMPACTION */
>  
>  static inline bool should_release_lock(spinlock_t *lock)
>  {

-- 
Michal Hocko
SUSE Labs