linux-kernel - Re: [PATCH] s390: allow reschedule on syscall restart

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Message-ID: <20210122083249.60d29c33@canb.auug.org.au>
Date:   Fri, 22 Jan 2021 08:32:49 +1100
From:   Stephen Rothwell <sfr@...b.auug.org.au>
To:     Sven Schnelle <svens@...ux.ibm.com>
Cc:     Linux Next Mailing List <linux-next@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Vasily Gorbik <gor@...ux.ibm.com>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Frederic Weisbecker <frederic@...nel.org>,
        "Paul E. McKenney" <paulmck@...nel.org>
Subject: Re: [PATCH] s390: allow reschedule on syscall restart

Hi all,

On Thu, 21 Jan 2021 15:39:26 +0100 Sven Schnelle <svens@...ux.ibm.com> wrote:
>
> Commit 845f44e8ef28 ("sched: Report local wake up on resched blind zone
> within idle loop") from next-20210121 causes a warning because s390
> doesn't call sched_resched_local_allow() when restarting a syscall.
> 
> Signed-off-by: Sven Schnelle <svens@...ux.ibm.com>
> ---
>  arch/s390/kernel/syscall.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/s390/kernel/syscall.c b/arch/s390/kernel/syscall.c
> index bc8e650e377d..2b39ac40f970 100644
> --- a/arch/s390/kernel/syscall.c
> +++ b/arch/s390/kernel/syscall.c
> @@ -162,6 +162,7 @@ void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
>  		do_syscall(regs);
>  		if (!test_pt_regs_flag(regs, PIF_SYSCALL_RESTART))
>  			break;
> +		sched_resched_local_allow();
>  		local_irq_enable();
>  	}
>  	exit_to_user_mode();

I add that today as a merge fixup patch to the merge of the rcu tree
(which contains commit 845f44e8ef28 ("sched: Report local wake up on
resched blind zone within idle loop") ).

-- 
Cheers,
Stephen Rothwell

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