Messages in this thread | | | Date | Wed, 26 Nov 2014 18:00:55 -0500 | From | Mike Snitzer <> | Subject | Re: virtio_blk: fix defaults for max_hw_sectors and max_segment_size |
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On Wed, Nov 26 2014 at 4:53pm -0500, Jens Axboe <axboe@kernel.dk> wrote:
> On 11/26/2014 02:51 PM, Mike Snitzer wrote: > > > > But while you're here, I wouldn't mind getting your take on virtio-blk > > setting max_hw_sectors to -1U. > > > > As I said in my original reply to mst: it only makes sense to set a > > really high initial upper bound like that in a driver if that driver > > goes on to stack an underlying device's limit. > > -1U should just work, IMHO, there's no reason we should need to cap it > at some synthetic value. That said, it seems it should be one of > those parameters that should be negotiated up and set appropriately.
I'm saying set it to the underlying device's value for max_hw_sectors -- not some synthetic value. So I think we're saying the same thing.
But it isn't immediately clear (to me) how that benefits virtio-blk users (obviously they are getting by today). So until that is pinned down I imagine nobody will care to extend the virtio-blk protocol to allow stacking max_hw_sectors and max_sectors up.
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