On Mon, Dec 10, 2012 at 01:21:23PM +1100, NeilBrown wrote: > On Thu, 22 Nov 2012 14:27:50 +0800 Guangliang Zhao <gzhao@xxxxxxxx> wrote: > > > Hi, > > > > These patches are used to add resync speed control for dm-raid1. The > > second and third patch provide support for user-space tool dmsetup. > > > > Guangliang Zhao (3): > > dm raid1: add resync speed control for dm-raid1 > > dm raid1: add interface to set resync speed > > dm raid1: add interface to get resync speed > > > > drivers/md/dm-raid1.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++-- > > 1 file changed, 90 insertions(+), 3 deletions(-) > > > > The problem with this approach is that it slows down resync even when there > is no other IO happening. > If that is deemed to be acceptable, then the patch set seems fine, though I > would probably make the default a lot higher so as not to change current > default behaviour for anyone. Yes, the users who don't need this feature will not be affected, fully accepted. > > If it isn't acceptable, then you either need to monitor the number of > requests going to the underlying devices - like md does - or monitor the > number of requests coming in to the dm-raid1 target - which is probably > easier with dm. > > i.e. only impose the rate limit if there have been any requests for the > dm-raid1 target in the last 'RESYNC_JIFFIES'. Good idea, that's would be on my TODO list. But anyway these patches are still required. > > What do you think of that? > > NeilBrown > -- > dm-devel mailing list > dm-devel@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/dm-devel -- Best regards, Guangliang -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
