From: Ming Lei <ming.lei@redhat.com>
To: Nilay Shroff <nilay@linux.ibm.com>
Cc: linux-block@vger.kernel.org, hch@lst.de, axboe@kernel.dk,
yi.zhang@redhat.com, czhong@redhat.com, yukuai@fnnas.com,
gjoyce@ibm.com
Subject: Re: [PATCHv4 3/5] block: introduce alloc_sched_data and free_sched_data elevator methods
Date: Tue, 11 Nov 2025 10:53:40 +0800 [thread overview]
Message-ID: <aRKlNI6bJWA5FbJL@fedora> (raw)
In-Reply-To: <20251110081457.1006206-4-nilay@linux.ibm.com>
On Mon, Nov 10, 2025 at 01:44:50PM +0530, Nilay Shroff wrote:
> The recent lockdep splat [1] highlights a potential deadlock risk
> involving ->elevator_lock and ->freeze_lock dependencies on -pcpu_alloc_
> mutex. The trace shows that the issue occurs when the Kyber scheduler
> allocates dynamic memory for its elevator data during initialization.
>
> To address this, introduce two new elevator operation callbacks:
> ->alloc_sched_data and ->free_sched_data. The subsequent patch would
> build upon these newly introduced methods to suppress lockdep splat[1].
>
> [1] https://lore.kernel.org/all/CAGVVp+VNW4M-5DZMNoADp6o2VKFhi7KxWpTDkcnVyjO0=-D5+A@mail.gmail.com/
>
> Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Thanks,
Ming
next prev parent reply other threads:[~2025-11-11 2:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-10 8:14 [PATCHv4 0/5] block: restructure elevator switch path and fix a lockdep splat Nilay Shroff
2025-11-10 8:14 ` [PATCHv4 1/5] block: unify elevator tags and type xarrays into struct elv_change_ctx Nilay Shroff
2025-11-11 6:55 ` Yu Kuai
2025-11-11 8:37 ` Nilay Shroff
2025-11-11 10:02 ` Yu Kuai
2025-11-11 12:00 ` Nilay Shroff
2025-11-10 8:14 ` [PATCHv4 2/5] block: move elevator tags into struct elevator_resources Nilay Shroff
2025-11-11 2:52 ` Ming Lei
2025-11-11 6:49 ` Nilay Shroff
2025-11-10 8:14 ` [PATCHv4 3/5] block: introduce alloc_sched_data and free_sched_data elevator methods Nilay Shroff
2025-11-11 2:53 ` Ming Lei [this message]
2025-11-11 7:20 ` Yu Kuai
2025-11-11 8:39 ` Nilay Shroff
2025-11-10 8:14 ` [PATCHv4 4/5] block: use {alloc|free}_sched data methods Nilay Shroff
2025-11-11 2:58 ` Ming Lei
2025-11-11 6:51 ` Nilay Shroff
2025-11-10 8:14 ` [PATCHv4 5/5] block: define alloc_sched_data and free_sched_data methods for kyber Nilay Shroff
2025-11-11 3:01 ` Ming Lei
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