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%.
[[email protected]: revert unneeded change to __add_to_swap_cache]
Signed-off-by: Shaohua Li <[email protected]>
Cc: Hugh Dickins <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
8 files changed
