[PATCH] SwapMig: add_to_swap() avoid atomic allocations

Add gfp_mask to add_to_swap

add_to_swap does allocations with GFP_ATOMIC in order not to interfere with
swapping.  During migration we may have use add_to_swap extensively which may
lead to out of memory errors.

This patch makes add_to_swap take a parameter that specifies the gfp mask.
The page migration code can then make add_to_swap use GFP_KERNEL.

Signed-off-by: Hirokazu Takahashi <taka@valinux.co.jp>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 997d838f0e70f7f028ee9daf75937c78b97a7cfd..eb591eaad1b7461af182422db9bc285230a68d6a 100644 (file)
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -198,7 +198,7 @@ extern int rw_swap_page_sync(int, swp_entry_t, struct page *);
 extern struct address_space swapper_space;
 #define total_swapcache_pages  swapper_space.nrpages
 extern void show_swap_cache_info(void);
-extern int add_to_swap(struct page *);
+extern int add_to_swap(struct page *, gfp_t);
 extern void __delete_from_swap_cache(struct page *);
 extern void delete_from_swap_cache(struct page *);
 extern int move_to_swap_cache(struct page *, swp_entry_t);

diff --git a/mm/swap_state.c b/mm/swap_state.c
index fc2aecb70a95c9e3559a2d4d1d4a2ae0700ebc50..7b09ac503fec9dde77422705a08b2a1f087d0d70 100644 (file)
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -141,7 +141,7 @@ void __delete_from_swap_cache(struct page *page)
  * Allocate swap space for the page and add the page to the
  * swap cache.  Caller needs to hold the page lock. 
  */
-int add_to_swap(struct page * page)
+int add_to_swap(struct page * page, gfp_t gfp_mask)
 {
        swp_entry_t entry;
        int err;
@@ -166,7 +166,7 @@ int add_to_swap(struct page * page)
                 * Add it to the swap cache and mark it dirty
                 */
                err = __add_to_swap_cache(page, entry,
-                               GFP_ATOMIC|__GFP_NOMEMALLOC|__GFP_NOWARN);
+                               gfp_mask|__GFP_NOMEMALLOC|__GFP_NOWARN);
 
                switch (err) {
                case 0:                         /* Success */

diff --git a/mm/vmscan.c b/mm/vmscan.c
index daed4a73b761c0abdff9367e9c23235f2598202f..5393b093a87ba898bb88aec37691bbd795186580 100644 (file)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -458,7 +458,7 @@ static int shrink_list(struct list_head *page_list, struct scan_control *sc)
                 * Try to allocate it some swap space here.
                 */
                if (PageAnon(page) && !PageSwapCache(page)) {
-                       if (!add_to_swap(page))
+                       if (!add_to_swap(page, GFP_ATOMIC))
                                goto activate_locked;
                }
 #endif /* CONFIG_SWAP */
@@ -715,7 +715,7 @@ redo:
                }
 
                if (PageAnon(page) && !PageSwapCache(page)) {
-                       if (!add_to_swap(page)) {
+                       if (!add_to_swap(page, GFP_KERNEL)) {
                                unlock_page(page);
                                list_move(&page->lru, &failed);
                                nr_failed++;