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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/swap.c
parent9800339b5e0f0e24ab3dac349e0de80d2018832e (diff)
downloadop-kernel-dev-33806f06da654092182410d974b6d3c5396ea3eb.zip
op-kernel-dev-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/swap.c')
-rw-r--r--mm/swap.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/swap.c b/mm/swap.c
index 6310dc2..8a529a0 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -855,9 +855,14 @@ EXPORT_SYMBOL(pagevec_lookup_tag);
void __init swap_setup(void)
{
unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT);
-
#ifdef CONFIG_SWAP
- bdi_init(swapper_space.backing_dev_info);
+ int i;
+
+ bdi_init(swapper_spaces[0].backing_dev_info);
+ for (i = 0; i < MAX_SWAPFILES; i++) {
+ spin_lock_init(&swapper_spaces[i].tree_lock);
+ INIT_LIST_HEAD(&swapper_spaces[i].i_mmap_nonlinear);
+ }
#endif
/* Use a smaller cluster for small-memory machines */
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