exfat: improve performance of exfat_free_cluster when using dirsync mount option
There are stressful update of cluster allocation bitmap when using
dirsync mount option which is doing sync buffer on every cluster bit
clearing. This could result in performance degradation when deleting
big size file.
Fix to update only when the bitmap buffer index is changed would make
less disk access, improving performance especially for truncate operation.
Testing with Samsung 256GB sdcard, mounted with dirsync option
(mount -t exfat /dev/block/mmcblk0p1 /temp/mount -o dirsync)
Remove 4GB file, blktrace result.
[Before] : 39 secs.
Total (blktrace):
Reads Queued: 0, 0KiB Writes Queued: 32775, 16387KiB
Read Dispatches: 0, 0KiB Write Dispatches: 32775, 16387KiB
Reads Requeued: 0 Writes Requeued: 0
Reads Completed: 0, 0KiB Writes Completed: 32775, 16387KiB
Read Merges: 0, 0KiB Write Merges: 0, 0KiB
IO unplugs: 2 Timer unplugs: 0
[After] : 1 sec.
Total (blktrace):
Reads Queued: 0, 0KiB Writes Queued: 13, 6KiB
Read Dispatches: 0, 0KiB Write Dispatches: 13, 6KiB
Reads Requeued: 0 Writes Requeued: 0
Reads Completed: 0, 0KiB Writes Completed: 13, 6KiB
Read Merges: 0, 0KiB Write Merges: 0, 0KiB
IO unplugs: 1 Timer unplugs: 0
Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com>
Acked-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
3 files changed
