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| author | Minchan Kim <minchan@kernel.org> | 2017-11-16 02:33:07 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-16 03:21:02 +0100 |
| commit | 0bcac06f27d7528591c27ac2b093ccd71c5d0168 (patch) | |
| tree | b8261d05b232e57a58a7fe90306cad5d545de900 /mm/page_io.c | |
| parent | mm, swap: introduce SWP_SYNCHRONOUS_IO (diff) | |
| download | linux-0bcac06f27d7528591c27ac2b093ccd71c5d0168.tar.xz linux-0bcac06f27d7528591c27ac2b093ccd71c5d0168.zip | |
mm, swap: skip swapcache for swapin of synchronous device
With fast swap storage, the platforms want to use swap more aggressively
and swap-in is crucial to application latency.
The rw_page() based synchronous devices like zram, pmem and btt are such
fast storage. When I profile swapin performance with zram lz4
decompress test, S/W overhead is more than 70%. Maybe, it would be
bigger in nvdimm.
This patch aims to reduce swap-in latency by skipping swapcache if the
swap device is synchronous device like rw_page based device. It
enhances 45% my swapin test(5G sequential swapin, no readahead, from
2.41sec to 1.64sec).
Link: http://lkml.kernel.org/r/1505886205-9671-5-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_io.c')
| -rw-r--r-- | mm/page_io.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/page_io.c b/mm/page_io.c index cd52b9cc169b..e93f1a4cacd7 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -347,7 +347,7 @@ out: return ret; } -int swap_readpage(struct page *page, bool do_poll) +int swap_readpage(struct page *page, bool synchronous) { struct bio *bio; int ret = 0; @@ -355,7 +355,7 @@ int swap_readpage(struct page *page, bool do_poll) blk_qc_t qc; struct gendisk *disk; - VM_BUG_ON_PAGE(!PageSwapCache(page), page); + VM_BUG_ON_PAGE(!PageSwapCache(page) && !synchronous, page); VM_BUG_ON_PAGE(!PageLocked(page), page); VM_BUG_ON_PAGE(PageUptodate(page), page); if (frontswap_load(page) == 0) { @@ -403,7 +403,7 @@ int swap_readpage(struct page *page, bool do_poll) count_vm_event(PSWPIN); bio_get(bio); qc = submit_bio(bio); - while (do_poll) { + while (synchronous) { set_current_state(TASK_UNINTERRUPTIBLE); if (!READ_ONCE(bio->bi_private)) break; |