Hi Miklos,
On Fri, Jan 07, 2011 at 07:22:41PM +0100, Miklos Szeredi wrote:
> Here's an updated patch, addressing the review comments.
>
> Hiroyuki-san, can you please review the newly introduced
> mem_cgroup_replace_cache_page(), as I'm not fully familiar with the
> memory cgroup code.
>
> Thanks,
> Miklos
> ---
>
> From: Miklos Szeredi <mszeredi@xxxxxxx>
> Subject: mm: add replace_page_cache_page() function
>
> This function basically does:
>
> remove_from_page_cache(old);
> page_cache_release(old);
> add_to_page_cache_locked(new);
>
> Except it does this atomically, so there's no possibility for the
> "add" to fail because of a race.
>
> This is used by fuse to move pages into the page cache.
>
> Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
> ---
> fs/fuse/dev.c | 10 +++------
> include/linux/memcontrol.h | 8 +++++++
> include/linux/pagemap.h | 1
> mm/filemap.c | 50 +++++++++++++++++++++++++++++++++++++++++++++
> mm/memcontrol.c | 38 ++++++++++++++++++++++++++++++++++
> 5 files changed, 101 insertions(+), 6 deletions(-)
>
> Index: linux-2.6/mm/filemap.c
> ===================================================================
> --- linux-2.6.orig/mm/filemap.c 2011-01-07 17:53:39.000000000 +0100
> +++ linux-2.6/mm/filemap.c 2011-01-07 19:14:45.000000000 +0100
> @@ -390,6 +390,56 @@ int filemap_write_and_wait_range(struct
> EXPORT_SYMBOL(filemap_write_and_wait_range);
>
> /**
> + * replace_page_cache_page - replace a pagecache page with a new one
> + * @old: page to be replaced
> + * @new: page to replace with
> + * @gfp_mask: page allocation mode
> + *
> + * This function replaces a page in the pagecache with a new one. On
> + * success it acquires the pagecache reference for the new page and
> + * drop it for the old page. Both the old and new pages must be
> + * locked. This function does not add the new page to the LRU, the
> + * caller must do that.
> + *
> + * The remove + add is atomic. The only way this function can fail is
> + * memory allocation failure.
> + */
> +int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
> +{
> + int error;
> +
> + VM_BUG_ON(!PageLocked(old));
> + VM_BUG_ON(!PageLocked(new));
> + VM_BUG_ON(new->mapping);
> +
> + error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM);
> + if (!error) {
> + struct address_space *mapping = old->mapping;
> + pgoff_t offset = old->index;
> +
> + page_cache_get(new);
> + new->mapping = mapping;
> + new->index = offset;
> +
> + spin_lock_irq(&mapping->tree_lock);
> + __remove_from_page_cache(old);
Since v1, I tried to change page reference accouting semantics of
remove_from_page_cache. At last, it changes API name from __remove_from_page_cache
to __delete_from_page_cache.
So this conflicts my series.
If you are not urgent, could you resend based on my series after Andrew merges it?
Or if Andrew has a concern about my series and he merged your patch, I will resend
my series include fixing this part of your patch.
Please wait Andrew's next step.
--
Kind regards,
Minchan Kim
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