[PATCH] swsusp: write speedup

Switch the swsusp writeout code from 4k-at-a-time to 4MB-at-a-time.

Crufty old PIII testbox:
	12.9 MB/s -> 20.9 MB/s

Sony Vaio:
	14.7 MB/s -> 26.5 MB/s

The implementation is crude.  A better one would use larger BIOs, but wouldn't
gain any performance.

The memcpys will be mostly pipelined with the IO and basically come for free.

The ENOMEM path has not been tested.  It should be.

Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/linux/swap.h b/include/linux/swap.h
index a2f5ad7c2d2e..3d434cbffe26 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -12,6 +12,8 @@
 
 struct notifier_block;
 
+struct bio;
+
 #define SWAP_FLAG_PREFER        0x8000  /* set if swap priority specified */
 #define SWAP_FLAG_PRIO_MASK     0x7fff
 #define SWAP_FLAG_PRIO_SHIFT    0
@@ -216,7 +218,8 @@ extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);
 /* linux/mm/page_io.c */
 extern int swap_readpage(struct file *, struct page *);
 extern int swap_writepage(struct page *page, struct writeback_control *wbc);
-extern int rw_swap_page_sync(int, swp_entry_t, struct page *);
+extern int rw_swap_page_sync(int rw, swp_entry_t entry, struct page *page,
+                                struct bio **bio_chain);
 
 /* linux/mm/swap_state.c */
 extern struct address_space swapper_space;