forge/linux-pinenote
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

mm: break up swap_writepage() for frontswap backends

Browse source 
swap_writepage() is currently where frontswap hooks into the swap write
path to capture pages with the frontswap_store() function.  However, if
a frontswap backend wants to "resume" the writeback of a page to the
swap device, it can't call swap_writepage() as the page will simply
reenter the backend.

This patch separates swap_writepage() into a top and bottom half, the
bottom half named __swap_writepage() to allow a frontswap backend, like
zswap, to resume writeback beyond the frontswap_store() hook.

__add_to_swap_cache() is also made non-static so that the page for which
writeback is to be resumed can be added to the swap cache.

Signed-off-by: Seth Jennings <sjenning@linux.vnet.ibm.com>
Signed-off-by: Bob Liu <bob.liu@oracle.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Seth Jennings 2013-04-29 15:08:34 -07:00 • committed by Linus Torvalds
commit 2f772e6cad
3 changed files with 14 additions and 4 deletions
Download patch file Download diff file Expand all files Collapse all files

2
include/linux/swap.h
View file

@ -330,6 +330,7 @@ static inline void mem_cgroup_uncharge_swap(swp_entry_t ent)
/* linux/mm/page_io.c */
extern int swap_readpage(struct page *);
extern int swap_writepage(struct page *page, struct writeback_control *wbc);
extern int __swap_writepage(struct page *page, struct writeback_control *wbc);
extern int swap_set_page_dirty(struct page *page);
extern void end_swap_bio_read(struct bio *bio, int err);
@ -345,6 +346,7 @@ extern unsigned long total_swapcache_pages(void);
extern void show_swap_cache_info(void);
extern int add_to_swap(struct page *);
extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
extern int __add_to_swap_cache(struct page *page, swp_entry_t entry);
extern void __delete_from_swap_cache(struct page *);
extern void delete_from_swap_cache(struct page *);
extern void free_page_and_swap_cache(struct page *);