On Tue, Nov 13 2018 at 8:28pm -0500, Mike Snitzer <snit...@redhat.com> wrote:
> On Tue, Nov 13 2018 at 7:51pm -0500, > Jens Axboe <ax...@kernel.dk> wrote: > > > On 11/13/18 5:41 PM, Guenter Roeck wrote: > > > Hi, > > > > > > On Wed, Oct 31, 2018 at 08:36:31AM -0600, Jens Axboe wrote: > > >> NVMe does round-robin between queues by default, which means that > > >> sharing a queue map for both reads and writes can be problematic > > >> in terms of read servicing. It's much easier to flood the queue > > >> with writes and reduce the read servicing. > > >> > > >> Implement two queue maps, one for reads and one for writes. The > > >> write queue count is configurable through the 'write_queues' > > >> parameter. > > >> > > >> By default, we retain the previous behavior of having a single > > >> queue set, shared between reads and writes. Setting 'write_queues' > > >> to a non-zero value will create two queue sets, one for reads and > > >> one for writes, the latter using the configurable number of > > >> queues (hardware queue counts permitting). > > >> > > >> Reviewed-by: Hannes Reinecke <h...@suse.com> > > >> Reviewed-by: Keith Busch <keith.bu...@intel.com> > > >> Signed-off-by: Jens Axboe <ax...@kernel.dk> > > > > > > This patch causes hangs when running recent versions of > > > -next with several architectures; see the -next column at > > > kerneltests.org/builders for details. Bisect log below; this > > > was run with qemu on alpha. Reverting this patch as well as > > > "nvme: add separate poll queue map" fixes the problem. > > > > I don't see anything related to what hung, the trace, and so on. > > Can you clue me in? Where are the test results with dmesg? > > > > How to reproduce? > > Think Guenter should've provided a full kerneltests.org url, but I had a > look and found this for powerpc with -next: > https://kerneltests.org/builders/next-powerpc-next/builds/998/steps/buildcommand/logs/stdio > > Has useful logs of the build failure due to block. Take that back, of course I only had a quick look and first scrolled to this fragment and thought "yeap shows block build failure" (not _really_): opt/buildbot/slave/next-next/build/kernel/sched/psi.c: In function 'cgroup_move_task': /opt/buildbot/slave/next-next/build/include/linux/spinlock.h:273:32: warning: 'rq' may be used uninitialized in this function [-Wmaybe-uninitialized] #define raw_spin_unlock(lock) _raw_spin_unlock(lock) ^~~~~~~~~~~~~~~~ /opt/buildbot/slave/next-next/build/kernel/sched/psi.c:639:13: note: 'rq' was declared here struct rq *rq; ^~
