On Thu, Nov 08 2018 at 9:52am -0500, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote: > On Tue, Nov 06, 2018 at 10:35:03PM +0100, Mikulas Patocka wrote: > > Device mapper was converted to percpu inflight counters. In order to > > display the correct values in the "inflight" sysfs file, we need a custom > > callback that sums the percpu counters. > > The attribute that calls this is per-partition, while your method > is per-queue, so there is some impedence mismatch here. > > Is there any way you could look into just making the generic code > use percpu counters? Discussed doing that with Jens and reported as much here: https://www.redhat.com/archives/dm-devel/2018-November/msg00068.html And Jens gave additional context for why yet another attempt to switch block core's in_flight to percpu counters is doomed (having already been proposed and rejected twice): https://www.redhat.com/archives/dm-devel/2018-November/msg00071.html And yes, definitely should've cc'd linux-block (now added). Mike
