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authorShaohua Li <shli@kernel.org>2013-02-22 16:34:37 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-23 17:50:17 -0800
commit33806f06da654092182410d974b6d3c5396ea3eb (patch)
tree7f7da99d94481a1d4c78ebf05b410fc8ba654a39 /mm/util.c
parent9800339b5e0f0e24ab3dac349e0de80d2018832e (diff)
downloadlinux-33806f06da654092182410d974b6d3c5396ea3eb.tar.gz
swap: make each swap partition have one address_space
When I use several fast SSD to do swap, swapper_space.tree_lock is heavily contended. This makes each swap partition have one address_space to reduce the lock contention. There is an array of address_space for swap. The swap entry type is the index to the array. In my test with 3 SSD, this increases the swapout throughput 20%. [akpm@linux-foundation.org: revert unneeded change to __add_to_swap_cache] Signed-off-by: Shaohua Li <shli@fusionio.com> Cc: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/util.c')
-rw-r--r--mm/util.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/mm/util.c b/mm/util.c
index 16a73195a37..ab1424dbe2e 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -6,6 +6,7 @@
#include <linux/sched.h>
#include <linux/security.h>
#include <linux/swap.h>
+#include <linux/swapops.h>
#include <asm/uaccess.h>
#include "internal.h"
@@ -389,9 +390,12 @@ struct address_space *page_mapping(struct page *page)
VM_BUG_ON(PageSlab(page));
#ifdef CONFIG_SWAP
- if (unlikely(PageSwapCache(page)))
- mapping = &swapper_space;
- else
+ if (unlikely(PageSwapCache(page))) {
+ swp_entry_t entry;
+
+ entry.val = page_private(page);
+ mapping = swap_address_space(entry);
+ } else
#endif
if ((unsigned long)mapping & PAGE_MAPPING_ANON)
mapping = NULL;