From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: George Dunlap <george.dunlap@citrix.com>,
Dario Faggioli <dfaggioli@suse.com>
Subject: Re: [RFC PATCH 01/10] sched: core: save IRQ state during locking
Date: Wed, 24 Feb 2021 18:29:30 +0000 [thread overview]
Message-ID: <c8475a6a-5a33-cc42-a909-b6d8dce61fab@citrix.com> (raw)
In-Reply-To: <20210223023428.757694-2-volodymyr_babchuk@epam.com>
On 23/02/2021 02:34, Volodymyr Babchuk wrote:
> With XEN preemption enabled, scheduler functions can be called with
> IRQs disabled (for example, at end of IRQ handler), so we should
> save and restore IRQ state in schedulers code.
>
> Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
These functions need to fixed not to be _irq() variants in the first place.
The only reason they're like that is so the schedule softirq/irq can
edit the runqueues. I seem to recall Dario having a plan to switch the
runqueues to using a lockless update mechanism, which IIRC removes any
need for any of the scheduler locks to be irqs-off.
~Andrew
next prev parent reply other threads:[~2021-02-24 18:29 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-23 2:34 [RFC PATCH 00/10] Preemption in hypervisor (ARM only) Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 01/10] sched: core: save IRQ state during locking Volodymyr Babchuk
2021-02-23 8:52 ` Jürgen Groß
2021-02-23 11:15 ` Volodymyr Babchuk
2021-02-24 18:29 ` Andrew Cooper [this message]
2021-02-23 2:34 ` [RFC PATCH 03/10] sched: credit2: " Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 02/10] sched: rt: " Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 04/10] preempt: use atomic_t to for preempt_count Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 05/10] preempt: add try_preempt() function Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 07/10] sched: core: remove ASSERT_NOT_IN_ATOMIC and disable preemption[!] Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 06/10] arm: setup: disable preemption during startup Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 08/10] arm: context_switch: allow to run with IRQs already disabled Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 10/10] [HACK] alloc pages: enable preemption early Volodymyr Babchuk
2021-02-23 2:34 ` [RFC PATCH 09/10] arm: traps: try to preempt before leaving IRQ handler Volodymyr Babchuk
2021-02-23 9:02 ` [RFC PATCH 00/10] Preemption in hypervisor (ARM only) Julien Grall
2021-02-23 12:06 ` Volodymyr Babchuk
2021-02-24 10:08 ` Julien Grall
2021-02-24 20:57 ` Volodymyr Babchuk
2021-02-24 22:31 ` Julien Grall
2021-02-24 23:58 ` Volodymyr Babchuk
2021-02-25 0:39 ` Andrew Cooper
2021-02-25 12:51 ` Volodymyr Babchuk
2021-03-05 9:31 ` Volodymyr Babchuk
2021-02-24 18:07 ` Andrew Cooper
2021-02-24 23:37 ` Volodymyr Babchuk
2021-03-01 14:39 ` George Dunlap
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