On Thu, Aug 27 2009 at 10:19am -0400, Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > On Thu, Aug 27 2009 at 9:12am -0400, > Alasdair G Kergon <agk@xxxxxxxxxx> wrote: > > > On Fri, Aug 21, 2009 at 10:17:18AM -0400, Mike Snitzer wrote: > > > Add .io_hints to 'struct target_type' to allow the I/O hints portion of > > > the 'struct queue_limits' to be set by each target. Expose dm-stripe > > > target's topology I/O hints. > > > > Do you still think this should go into 2.6.31? > > Yes, it is important. Otherwise DM won't expose the proper I/O hints in > /sys for a striped device. This is bad because then higher-level tools > won't be able to rely on that information to properly align ther data > (e.g. mkfs.extX -E). > > > If so, please supply a revised patch header that explains the benefits > > of having the patch (and reference the new stuff in 2.6.31 that it > > uses). > > > > > + limits->io_opt = chunk_size * sc->stripes; > > > > blk_queue_io_opt() ? Did you mean why not use blk_limits_io_opt()? > Martin didn't expose such an interface because all existing code (both > DM and MD) does not require anything beyond a simple assignment. I > worked with Martin to establish the blk_queue_io_min() precisely because > DM needed to avoid duplicating the block layer's logic. I think Martin > stopped short of adding a symmetric wrapper for setting io_opt because > he felt it was unnecessary. But I could be mis-remembering. To clarify further; I meant to say blk_limits_io_min() in my above paragraph. We don't have access to the queue (because target's don't have a queue); we're working with 'struct queue_limits *limits' Mike -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
