2012/3/14 Holger Kiehl <Holger.Kiehl@xxxxxx>: > On Wed, 14 Mar 2012, Shaohua Li wrote: > >> 2012/3/13 Holger Kiehl <Holger.Kiehl@xxxxxx>: >>> >>> On Tue, 13 Mar 2012, Shaohua Li wrote: >>> >>>> Thanks for testing. This is very wield, the req->__data_len is wrong. >>>> Is this a clean build? >>>> >>> I just downloaded linux-3.3-rc7.tar.bz2 from kernel.org and applied >>> your patches again. The result is the same. >>> >>> Am I the only one experiencing these problems? >> >> Martin Petersen pointed out scsi layer doesn't support discard merge, >> which >> might be the reason you see the error message (my drive isn't a scsi >> device). >> can you please try attached patch? >> > Thanks! After this patch the error messages are away. > > However, when the system boots it takes a very long time to boot: > > [ 16.527389] EXT4-fs (md0): mounted filesystem with ordered data mode. > Opts: discard,commit=2400,journal_async_commit > [ 24.218410] EXT4-fs (md2): mounted filesystem with ordered data mode. > Opts: discard,commit=600,journal_async_commit > [ 69.823138] udevd[474]: timeout '/sbin/blkid -o udev -p /dev/md0' > [ 70.824197] udevd[474]: timeout: killing '/sbin/blkid -o udev -p > /dev/md0' [866] > [ 70.826823] udevd[474]: '/sbin/blkid -o udev -p /dev/md0' [866] > terminated by signal 9 (Killed) > [ 70.829290] udevd[474]: timeout 'udisks-part-id /dev/md0' > [ 74.942625] udevd[475]: timeout '/sbin/blkid -o udev -p /dev/md2' > [ 75.947158] udevd[475]: timeout: killing '/sbin/blkid -o udev -p > /dev/md2' [874] > [ 75.949734] udevd[475]: '/sbin/blkid -o udev -p /dev/md2' [874] > terminated by signal 9 (Killed) > [ 75.951945] udevd[475]: timeout 'udisks-part-id /dev/md2' > [ 79.023741] rmmod[886]: ERROR: Module scsi_wait_scan does not exist in > /proc/modules > [ 96.005919] systemd[1]: dev-md3.swap activation timed out. Stopping. > [ 127.292002] Adding 9434108k swap on /dev/md3. Priority:0 extents:1 > across:9434108k > > During another boot I saw this additional message: > > [ 11.988732] scsi_verify_blk_ioctl: 930 callbacks suppressed > > The strange thing is that after boot I tried to enter the command > '/sbin/blkid -o udev -p /dev/md0' and it works without any problems > (time for this is 0m0.001s). So I also tried booting without discard > option, but the result is the same. > > Otherwise I observed no problems. Even running some more extensive > benchmark testing showed no problems. Only the performance drop is > dramatic. In my own benchmark where thousand of files get copied around > via FTP the performance drops from 4000 files per second to 520 when > mounting the filesystem with discard option. Also during the benchmark > any access to the disk can take very very long if discard is enabled. > > Next, I will try this patch on a system without SATA/SCSI disks. Maybe the discard runs slow with small size request in the disk. please drop patch "blk: add plug for blkdev_issue_discard" and try again. Since we can't do merge, the plug just introduces latency. if it doesn't help, please capture a blktrace when you do the benchmark and send it to me. Thanks, Shaohua -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
