linux-kernel - Re: [PATCH V2] blk-cgroup: prevent rcu_sched detected stalls warnings while iterating blkgs

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Date:   Wed, 7 Jul 2021 09:38:54 -0600
From:   Jens Axboe <axboe@...nel.dk>
To:     Yu Kuai <yukuai3@...wei.com>, tj@...nel.org
Cc:     cgroups@...r.kernel.org, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org, yi.zhang@...wei.com
Subject: Re: [PATCH V2] blk-cgroup: prevent rcu_sched detected stalls warnings
 while iterating blkgs

On 7/6/21 7:56 PM, Yu Kuai wrote:
> We run a test that create millions of cgroups and blkgs, and then trigger
> blkg_destroy_all(). blkg_destroy_all() will hold spin lock for a long
> time in such situation. Thus release the lock when a batch of blkgs are
> destroyed.
> 
> blkcg_activate_policy() and blkcg_deactivate_policy() might have the
> same problem, however, as they are basically only called from module
> init/exit paths, let's leave them alone for now.

Applied, thanks.

-- 
Jens Axboe