Re: [PATCH 6/6] blk-mq-debugfs: Add 'kick' operation

On 05/02/2017 10:23 AM, Bart Van Assche wrote:

On Mon, 2017-05-01 at 18:24 -0600, Jens Axboe wrote:

quoted

On 05/01/2017 06:19 PM, Omar Sandoval wrote:

quoted

On Thu, Apr 27, 2017 at 08:54:37AM -0700, Bart Van Assche wrote:

quoted

Running a queue causes the block layer to examine the per-CPU and
hw queues but not the requeue list. Hence add a 'kick' operation
that also examines the requeue list.

The naming of these operations isn't super intuitive, but it makes
enough sense if you know the code, I guess.

I don't worry about that too much, but I do think it's important
that we have some way of knowing WHAT commands are available
for a given kernel, without having to consult the source. It's
no big deal you're running the latest and greatest debug kernels,
but it's a bigger issue if you're debugging kernel x.y.z for
a customer and you have to consult the source to find them.

Can we include it in the show output?

Hello Jens,

Sorry but I'm afraid that including the list of supported commands in the
'show' output would make that output harder to read. Figuring out what the
supported commands are is not that hard as the output below shows:

# dmesg -c >/dev/null; for d in /sys/kernel/debug/block/*/mq/state; do \
  if [ -e "$d" ]; then echo help >$d 2>/dev/null; break; fi; done; dmesg
blk_queue_flags_store: unsupported operation help. Use 'run', 'start' or 'kick'

Ah perfect, I missed that. That's perfectly fine, all I care about is
that there is some way to tell what the valid commands are, without
having to find the source.

-- 
Jens Axboe