On Thu, Jun 02, 2011 at 10:17:16AM -0400, Vivek Goyal wrote: > On Thu, Jun 02, 2011 at 11:22:09AM +1000, Dave Chinner wrote: > > On Wed, Jun 01, 2011 at 05:50:49PM -0400, Vivek Goyal wrote: > > > Hi, > > > > > > If I throttle a DIO/AIO WRITE bio at block device in a cgroup, will it > > > lead to any kind of serialization of ext4 file system. IOW, is there any > > > filesystem operation which will wait for that DIO/AIO WRITE to finish > > > before other filesystem can make progress (fsync, journalling etc?) > > > > Truncate? > > > > (XFS explicitly serialises truncate against in flight DIO, > > regardless of whether ext4 does.) > > > > Dave, > > Does this serialization happens against that particular inode on which > truncate has been called? If yes, then I think I will still be fine > as in common use case I am not expecting much sharing of inodes across > cgroups. Dave, I did a quick test of throttling a direct IO on one file and then doing "truncate -s 40 testfile" on a different file in different cgroup and it seems to work fine. But I seem to be having issues with "sync". Looks like in ext4, if I throttle a DIO, sync does not hang but in XFS it does. I am wondering if XFS is waiting for all inflight DIO to finish before sync completes. Thanks Vivek -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
