[PATCH] mm: Add hook of freepage

[PATCH] mm: Add hook of freepage

[Minchan Kim]

Recently, "Call the filesystem back whenever a page is removed from
the page cache(6072d13c)" added new freepage hook in page cache
drop function.

So, replace_page_cache_page should call freepage to support
page cleanup to fs.

Cc: Miklos Szeredi <mszeredi@suse.cz>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
---
 mm/filemap.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 3c89c96..a25c898 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -436,7 +436,10 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
 	error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
 	if (!error) {
 		struct address_space *mapping = old->mapping;
+		void (*freepage)(struct page *);
+
 		pgoff_t offset = old->index;
+		freepage = mapping->a_ops->freepage;
 
 		page_cache_get(new);
 		new->mapping = mapping;
@@ -452,6 +455,8 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
 			__inc_zone_page_state(new, NR_SHMEM);
 		spin_unlock_irq(&mapping->tree_lock);
 		radix_tree_preload_end();
+		if (freepage)
+			freepage(old);
 		page_cache_release(old);
 		mem_cgroup_end_migration(memcg, old, new, true);
 	} else {
-- 
1.7.1

Re: [PATCH] mm: Add hook of freepage

[Rik van Riel]

On 02/06/2011 10:08 AM, Minchan Kim wrote:
> Recently, "Call the filesystem back whenever a page is removed from
> the page cache(6072d13c)" added new freepage hook in page cache
> drop function.
>
> So, replace_page_cache_page should call freepage to support
> page cleanup to fs.
>
> Cc: Miklos Szeredi<mszeredi@suse.cz>
> Cc: Rik van Riel<riel@redhat.com>
> Cc: KAMEZAWA Hiroyuki<kamezawa.hiroyu@jp.fujitsu.com>
> Cc: Mel Gorman<mel@csn.ul.ie>
> Signed-off-by: Minchan Kim<minchan.kim@gmail.com>

Acked-by: Rik van Riel <riel@redhat.com>

-- 
All rights reversed

Re: [PATCH] mm: Add hook of freepage

[Miklos Szeredi]

On Mon, 2011-02-07 at 00:08 +0900, Minchan Kim wrote:
> Recently, "Call the filesystem back whenever a page is removed from
> the page cache(6072d13c)" added new freepage hook in page cache
> drop function.
> 
> So, replace_page_cache_page should call freepage to support
> page cleanup to fs.

Thanks Minchan for fixing this.

Acked-by: Miklos Szeredi <mszeredi@suse.cz>

> 
> Cc: Miklos Szeredi <mszeredi@suse.cz>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Cc: Mel Gorman <mel@csn.ul.ie>
> Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
> ---
>  mm/filemap.c |    5 +++++
>  1 files changed, 5 insertions(+), 0 deletions(-)
> 
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 3c89c96..a25c898 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -436,7 +436,10 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
>  	error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
>  	if (!error) {
>  		struct address_space *mapping = old->mapping;
> +		void (*freepage)(struct page *);
> +
>  		pgoff_t offset = old->index;
> +		freepage = mapping->a_ops->freepage;
>  
>  		page_cache_get(new);
>  		new->mapping = mapping;
> @@ -452,6 +455,8 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
>  			__inc_zone_page_state(new, NR_SHMEM);
>  		spin_unlock_irq(&mapping->tree_lock);
>  		radix_tree_preload_end();
> +		if (freepage)
> +			freepage(old);
>  		page_cache_release(old);
>  		mem_cgroup_end_migration(memcg, old, new, true);
>  	} else {

Re: [PATCH] mm: Add hook of freepage

[Andrew Morton]

On Mon, 07 Feb 2011 10:37:01 +0100
Miklos Szeredi <mszeredi@suse.cz> wrote:

> On Mon, 2011-02-07 at 00:08 +0900, Minchan Kim wrote:
> > Recently, "Call the filesystem back whenever a page is removed from
> > the page cache(6072d13c)" added new freepage hook in page cache
> > drop function.
> > 
> > So, replace_page_cache_page should call freepage to support
> > page cleanup to fs.
> 
> Thanks Minchan for fixing this.

What's happening with mm-add-replace_page_cache_page-function.patch,
btw?  When last discussed nearly three weeks ago we had identified:

1) remove radix_tree_preload
2) single radix_tree_lookup_slot and replace radix tree slot
3) page accounting optimization if both pages are in same zone.