From: Julien Grall <julien@xen.org>
To: Bertrand Marquis <Bertrand.Marquis@arm.com>
Cc: Jens Wiklander <jens.wiklander@linaro.org>,
Xen-devel <xen-devel@lists.xenproject.org>,
"patches@linaro.org" <patches@linaro.org>,
Stefano Stabellini <sstabellini@kernel.org>,
Michal Orzel <michal.orzel@amd.com>,
Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>
Subject: Re: [XEN PATCH v3 5/5] xen/arm: ffa: support notification
Date: Mon, 29 Apr 2024 21:55:47 +0100 [thread overview]
Message-ID: <72eef04f-b155-4f7e-a216-146f3dce993c@xen.org> (raw)
In-Reply-To: <1A23083C-9605-4291-AF2F-5891AF270333@arm.com>
Hi Bertrand,
On 29/04/2024 08:20, Bertrand Marquis wrote:
> From the comment in sched.h:
> /*
> * rcu_lock_domain_by_id() is more efficient than get_domain_by_id().
> * This is the preferred function if the returned domain reference
> * is short lived, but it cannot be used if the domain reference needs
> * to be kept beyond the current scope (e.g., across a softirq).
> * The returned domain reference must be discarded using rcu_unlock_domain().
> */
>
> Now the question of short lived should be challenged but I do not think we can
> consider the current code as "long lived".
Actually, I am not entirely sure you can use put_domain() in interrupt
context. If you look at the implementation of domain_destroy() it takes
a spin lock without disabling the interrupts.
The same spinlock is taken in domain_create(). So there is a potential
deadlock.
Which means the decision between the two is not only about liveness.
Cheers,
--
Julien Grall
next prev parent reply other threads:[~2024-04-29 20:56 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-26 8:47 [XEN PATCH v3 0/5] FF-A notifications Jens Wiklander
2024-04-26 8:47 ` [XEN PATCH v3 1/5] xen/arm: ffa: refactor ffa_handle_call() Jens Wiklander
2024-04-26 8:47 ` [XEN PATCH v3 2/5] xen/arm: ffa: use ACCESS_ONCE() Jens Wiklander
2024-04-26 8:47 ` [XEN PATCH v3 3/5] xen/arm: ffa: simplify ffa_handle_mem_share() Jens Wiklander
2024-04-26 8:47 ` [XEN PATCH v3 4/5] xen/arm: allow dynamically assigned SGI handlers Jens Wiklander
2024-04-26 8:47 ` [XEN PATCH v3 5/5] xen/arm: ffa: support notification Jens Wiklander
2024-04-26 9:20 ` Bertrand Marquis
2024-04-26 12:11 ` Jens Wiklander
2024-04-26 12:19 ` Bertrand Marquis
2024-04-26 12:32 ` Jens Wiklander
2024-04-26 12:41 ` Bertrand Marquis
2024-04-26 13:02 ` Jens Wiklander
2024-04-26 15:12 ` Bertrand Marquis
2024-04-26 18:31 ` Julien Grall
2024-04-26 17:58 ` Julien Grall
2024-04-29 9:55 ` Jens Wiklander
2024-04-26 19:07 ` Julien Grall
2024-04-29 7:20 ` Bertrand Marquis
2024-04-29 9:49 ` Jens Wiklander
2024-04-29 20:55 ` Julien Grall [this message]
2024-04-29 8:43 ` Jens Wiklander
2024-04-26 9:23 ` [XEN PATCH v3 0/5] FF-A notifications Bertrand Marquis
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