From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: blk-mq request allocation stalls [was: Re: [PATCH v3 0/8] dm: add request-based blk-mq support] Date: Fri, 9 Jan 2015 17:25:43 -0500 Message-ID: <20150109222543.GA1190@redhat.com> References: <54ABAB80.70006@acm.org> <20150106160553.GB10224@redhat.com> <54AC0A39.90801@kernel.dk> <54AD0B63.3010505@acm.org> <20150109194955.GA32641@redhat.com> <54B042FE.2000205@kernel.dk> <54B043FC.8000902@kernel.dk> <20150109214015.GA1032@redhat.com> <54B04E94.3010403@kernel.dk> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <54B04E94.3010403@kernel.dk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Jens Axboe Cc: Keith Busch , Christoph Hellwig , device-mapper development , Bart Van Assche , Jun'ichi Nomura List-Id: dm-devel.ids On Fri, Jan 09 2015 at 4:56pm -0500, Jens Axboe wrote: > On 01/09/2015 02:40 PM, Mike Snitzer wrote: > >On Fri, Jan 09 2015 at 4:11pm -0500, > >Jens Axboe wrote: > > > >> > >>Actually, try this one instead, it should be a bit more precise than > >>the first. > >> > > > >Thanks for the test patch. > > > >I'm still seeing failures that look wrong (last_tag=127 could be edge > >condition not handled properly?): > > > >[ 14.254632] __bt_get: values before for loop: last_tag=127, index=3 > >[ 14.255841] __bt_get: values after for loop: last_tag=64, index=2 > >[ 14.257036] > >[ 14.257036] bt_get: __bt_get() returned -1 > >[ 14.258051] queue_num=0, nr_tags=128, reserved_tags=0, bits_per_word=5 > >[ 14.259246] nr_free=128, nr_reserved=0 > >[ 14.259963] active_queues=0 > > > >[ 213.115997] __bt_get: values before for loop: last_tag=127, index=3 > >[ 213.117115] __bt_get: values after for loop: last_tag=96, index=3 > >[ 213.118200] > >[ 213.118200] bt_get: __bt_get() returned -1 > >[ 213.121593] queue_num=0, nr_tags=128, reserved_tags=0, bits_per_word=5 > >[ 213.123960] nr_free=128, nr_reserved=0 > >[ 213.125880] active_queues=0 > > > >[ 239.158079] __bt_get: values before for loop: last_tag=8, index=0 > >[ 239.160363] __bt_get: values after for loop: last_tag=0, index=0 > >[ 239.162896] > >[ 239.162896] bt_get: __bt_get() returned -1 > >[ 239.166284] queue_num=0, nr_tags=128, reserved_tags=0, bits_per_word=5 > >[ 239.168623] nr_free=127, nr_reserved=0 > >[ 239.170508] active_queues=0 > > Thanks for testing, can you try this one? Huh, at least now we're now seeing some nr_free=0... but the last 3 failures below look unnecessary still. E.g. the last_tag=127 case [ 13.895265] __bt_get: values before for loop: last_tag=59, index=1 [ 13.895265] __bt_get: values after for loop: last_tag=32, index=1 [ 13.895266] [ 13.895266] bt_get: __bt_get() returned -1 [ 13.895267] queue_num=0, nr_tags=128, reserved_tags=0, bits_per_word=5 [ 13.895267] nr_free=0, nr_reserved=0 [ 13.895268] active_queues=0 [ 13.895269] __bt_get: values before for loop: last_tag=0, index=0 [ 13.895270] __bt_get: values after for loop: last_tag=0, index=0 [ 13.895270] [ 13.895270] bt_get: __bt_get() returned -1 [ 13.895271] queue_num=0, nr_tags=128, reserved_tags=0, bits_per_word=5 [ 13.895272] nr_free=0, nr_reserved=0 [ 13.895272] active_queues=0 [ 13.895324] __bt_get: values before for loop: last_tag=0, index=0 [ 13.895324] __bt_get: values after for loop: last_tag=0, index=0 [ 13.895325] bt_get: __bt_get() _still_ returned -1 [ 13.895325] queue_num=0, nr_tags=128, reserved_tags=0, bits_per_word=5 [ 13.895326] nr_free=0, nr_reserved=0 [ 13.895326] active_queues=0 [ 18.931425] __bt_get: values before for loop: last_tag=127, index=3 [ 18.933317] __bt_get: values after for loop: last_tag=0, index=0 [ 18.935140] [ 18.935140] bt_get: __bt_get() returned -1 [ 18.936807] queue_num=0, nr_tags=128, reserved_tags=0, bits_per_word=5 [ 18.938772] nr_free=128, nr_reserved=0 [ 18.939927] active_queues=0 [ 489.119597] __bt_get: values before for loop: last_tag=95, index=2 [ 489.120621] __bt_get: values after for loop: last_tag=96, index=3 [ 489.121624] [ 489.121624] bt_get: __bt_get() returned -1 [ 489.122532] queue_num=0, nr_tags=128, reserved_tags=0, bits_per_word=5 [ 489.123581] nr_free=128, nr_reserved=0 [ 489.124206] active_queues=0 [ 494.705758] __bt_get: values before for loop: last_tag=127, index=3 [ 494.707797] __bt_get: values after for loop: last_tag=0, index=0 [ 494.709696] [ 494.709696] bt_get: __bt_get() returned -1 [ 494.712459] queue_num=0, nr_tags=128, reserved_tags=0, bits_per_word=5 [ 494.714403] nr_free=128, nr_reserved=0 [ 494.715955] active_queues=0