md/raid10: improve raid10 discard request
Now the discard request is split by chunk size. So it takes a long time to finish mkfs on disks which support discard function. This patch improve handling raid10 discard request. It uses the similar way with patch 29efc390 (md/md0: optimize raid0 discard handling). But it's a little complex than raid0. Because raid10 has different layout. If raid10 is offset layout and the discard request is smaller than stripe size. There are some holes when we submit discard bio to underlayer disks. For example: five disks (disk1 - disk5) D01 D02 D03 D04 D05 D05 D01 D02 D03 D04 D06 D07 D08 D09 D10 D10 D06 D07 D08 D09 The discard bio just wants to discard from D03 to D10. For disk3, there is a hole between D03 and D08. For disk4, there is a hole between D04 and D09. D03 is a chunk, raid10_write_request can handle one chunk perfectly. So the part that is not aligned with stripe size is still handled by raid10_write_request. If reshape is running when discard bio comes and the discard bio spans the reshape position, raid10_write_request is responsible to handle this discard bio. I did a test with this patch set. Without patch: time mkfs.xfs /dev/md0 real4m39.775s user0m0.000s sys0m0.298s With patch: time mkfs.xfs /dev/md0 real0m0.105s user0m0.000s sys0m0.007s nvme3n1 259:1 0 477G 0 disk └─nvme3n1p1 259:10 0 50G 0 part nvme4n1 259:2 0 477G 0 disk └─nvme4n1p1 259:11 0 50G 0 part nvme5n1 259:6 0 477G 0 disk └─nvme5n1p1 259:12 0 50G 0 part nvme2n1 259:9 0 477G 0 disk └─nvme2n1p1 259:15 0 50G 0 part nvme0n1 259:13 0 477G 0 disk └─nvme0n1p1 259:14 0 50G 0 part Reviewed-by:Coly Li <colyli@suse.de> Reviewed-by:
Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Tested-by:
Adrian Huang <ahuang12@lenovo.com> Signed-off-by:
Xiao Ni <xni@redhat.com> Signed-off-by:
Song Liu <songliubraving@fb.com>
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