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authorChao Yu <chao2.yu@samsung.com>2016-01-23 11:23:55 +0300
committerJaegeuk Kim <jaegeuk@kernel.org>2016-02-23 03:07:23 +0300
commit718e53fa633f84d09acb4b76f1ad572ccbf75a12 (patch)
tree8af154aa74c51905cc7f5d5db193902346868963 /fs/f2fs/dir.c
parente3ef18762f5757d3fb86f75ca59315db6d17d719 (diff)
downloadlinux-718e53fa633f84d09acb4b76f1ad572ccbf75a12.tar.xz
f2fs: enhance foreground GC
If we configure section consist of multiple segments, foreground GC will do the garbage collection with following approach: for each segment in victim section blk_start_plug for each valid block in segment write out by OPU method submit bio cache <--- blk_finish_plug <--- There are two issue: 1) for most of the time, 'submit bio cache' will break the merging in current bio buffer from writes of next segments, making a smaller bio submitting. 2) block plug only cover IO submitting in one segment, which reduce opportunity of merging IOs in plug with multiple segments. So refactor the code as below structure to strive for biggest opportunity of merging IOs: blk_start_plug for each segment in victim section for each valid block in segment write out by OPU method submit bio cache blk_finish_plug Test method: 1. mkfs.f2fs -s 8 /dev/sdX 2. touch 32 files 3. write 2M data into each file 4. punch 1.5M data from offset 0 for each file 5. trigger foreground gc through ioctl Before patch, there are totoally 40 bios submitted. f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 65536, size = 122880 f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 65776, size = 122880 f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 66016, size = 122880 f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 66256, size = 122880 f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 66496, size = 32768 ----repeat for 8 times After patch, there are totally 35 bios submitted. f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 65536, size = 122880 ----repeat 34 times f2fs_submit_write_bio: dev = (8,32), WRITE_SYNC, DATA, sector = 73696, size = 16384 Signed-off-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/dir.c')
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