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Subject: Re: [PATCH] block: increase BLKCG_MAX_POLS
To:     Oleksandr Natalenko <oleksandr@natalenko.name>,
        linux-kernel@vger.kernel.org
Cc:     linux-block@vger.kernel.org, Ming Lei <ming.lei@redhat.com>,
        Christoph Hellwig <hch@lst.de>,
        Laurence Oberman <loberman@redhat.com>,
        Paolo Valente <paolo.valente@linaro.org>,
        David Jeffery <djeffery@redhat.com>,
        Bart Van Assche <bvanassche@acm.org>
References: <20210717123328.945810-1-oleksandr@natalenko.name>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <32f6b089-46fa-55ec-ce7c-88da7e224728@kernel.dk>
Date:   Sat, 17 Jul 2021 13:07:09 -0600
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Precedence: bulk

On 7/17/21 6:33 AM, Oleksandr Natalenko wrote:
> After mq-deadline learnt to deal with cgroups, the BLKCG_MAX_POLS value
> became too small for all the elevators to be registered properly. The
> following issue is seen:
> 
> ```
> calling  bfq_init+0x0/0x8b @ 1
> blkcg_policy_register: BLKCG_MAX_POLS too small
> initcall bfq_init+0x0/0x8b returned -28 after 507 usecs
> ```
> 
> and BFQ is non-functional.
> 
> Increase BLKCG_MAX_POLS to allow space for everyone

LGTM, just needs a:

Fixes: 08a9ad8bf607 ("block/mq-deadline: Add cgroup support")

in there too, I'll add it.

-- 
Jens Axboe