Re: [RFC PATCH v1 00/17] blk-cgroup: protect blkgs with blkcg_mutex

Christoph Hellwig <[email protected]> Thu, 9 Jul 2026 08:09:59 +0200

Newsgroups	org.kernel.vger.linux-bcache,dev.linux.lists.dm-devel,org.infradead.lists.linux-nvme,org.kernel.vger.cgroups,org.kernel.vger.linux-block
Message-ID	<[email protected]>

On Sun, Jul 05, 2026 at 03:51:07AM +0800, Yu Kuai wrote:
> From: Yu Kuai <[email protected]>
> 
> This RFC moves queue-local blkg topology synchronization from
> q->queue_lock to q->blkcg_mutex.
> 
> q->queue_lock is a hot block-layer spinlock used by request queue runtime
> paths,

I don't think it is hot any more.  If it is in one of your workloads
we have a deep problem somewhere.  That being said, futher removing
uses of his old catch-all lock is always good, hopefully we can
eventually remove it entirely.

So this series looks great to me conceptually, but I'm unfortunately
not a very qualified reviewer for the blk-cgroup code.