From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH 4/5] blk-mq-debugfs: Show busy requests From: Jens Axboe To: Bart Van Assche Cc: "hch@lst.de" , "linux-block@vger.kernel.org" , "hare@suse.com" , "osandov@fb.com" , "ming.lei@redhat.com" References: <20170525233810.23211-1-bart.vanassche@sandisk.com> <20170525233810.23211-5-bart.vanassche@sandisk.com> <1495833461.2634.7.camel@sandisk.com> <0c124a6c-8c2d-1fb9-118f-96ce7fadc64c@kernel.dk> Message-ID: Date: Fri, 26 May 2017 15:21:33 -0600 MIME-Version: 1.0 In-Reply-To: <0c124a6c-8c2d-1fb9-118f-96ce7fadc64c@kernel.dk> Content-Type: text/plain; charset=utf-8 List-ID: On 05/26/2017 03:20 PM, Jens Axboe wrote: > On 05/26/2017 03:17 PM, Bart Van Assche wrote: >> On Fri, 2017-05-26 at 07:26 -0600, Jens Axboe wrote: >>> On 05/25/2017 05:38 PM, Bart Van Assche wrote: >>>> Requests that got stuck in a block driver are neither on >>>> blk_mq_ctx.rq_list nor on any hw dispatch queue. Make these >>>> visible in debugfs through the "busy" attribute. >>>> >>>> Signed-off-by: Bart Van Assche >>>> Cc: Christoph Hellwig >>>> Cc: Hannes Reinecke >>>> Cc: Omar Sandoval >>>> Cc: Ming Lei >>>> --- >>>> block/blk-mq-debugfs.c | 25 +++++++++++++++++++++++++ >>>> 1 file changed, 25 insertions(+) >>>> >>>> diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c >>>> index 8b06a12c1461..70a2b955afee 100644 >>>> --- a/block/blk-mq-debugfs.c >>>> +++ b/block/blk-mq-debugfs.c >>>> @@ -370,6 +370,30 @@ static const struct seq_operations hctx_dispatch_seq_ops = { >>>> .show = blk_mq_debugfs_rq_show, >>>> }; >>>> >>>> +struct show_busy_ctx { >>>> + struct seq_file *m; >>>> + struct blk_mq_hw_ctx *hctx; >>>> +}; >>>> + >>>> +static void hctx_show_busy(struct request *rq, void *data, bool reserved) >>>> +{ >>>> + const struct show_busy_ctx *ctx = data; >>> >>> Let's not call that variable 'ctx', in blk-mq that's pretty much >>> reserved for the sw queues. >> >> Hello Jens, >> >> How about renaming show_busy_ctx into show_busy_params and ctx into params? > > I think that would be an improvement. Also, this: > > blk_mq_debugfs_rq_show(ctx->m, &rq->queuelist); > > doesn't look safe at all, as you are passing in a node instead of a > head. I think you just want to use __blk_mq_debugfs_rq_show() here. I guess it's safe as we don't iterate the list, but it's pointless though. Just use __blk_mq_debugfs_rq_show(). -- Jens Axboe