linux-kernel - Re: [PATCH for-next] futex: deduplicate resched in futex_wake

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Date:   Thu, 20 May 2021 11:16:00 -0700
From:   Davidlohr Bueso <dave@...olabs.net>
To:     Pavel Begunkov <asml.silence@...il.com>
Cc:     linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Darren Hart <dvhart@...radead.org>
Subject: Re: [PATCH for-next] futex: deduplicate resched in futex_wake_op()

On Mon, 17 May 2021, Pavel Begunkov wrote:

>After pagefaulting in futex_wake_op() both branches do cond_resched()
>before retry. Help to deduplicate it as many compilers can't cope with
>it.
>

LGTM:

Reviewed-by: Davidlohr Bueso <dbueso@...e.de>

>Signed-off-by: Pavel Begunkov <asml.silence@...il.com>
>---
> kernel/futex.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
>diff --git a/kernel/futex.c b/kernel/futex.c
>index c98b825da9cf..54ed232b2553 100644
>--- a/kernel/futex.c
>+++ b/kernel/futex.c
>@@ -1728,12 +1728,9 @@ futex_wake_op(u32 __user *uaddr1, unsigned int flags, u32 __user *uaddr2,
> 				return ret;
> 		}
>
>-		if (!(flags & FLAGS_SHARED)) {
>-			cond_resched();
>-			goto retry_private;
>-		}
>-
> 		cond_resched();
>+		if (!(flags & FLAGS_SHARED))
>+			goto retry_private;
> 		goto retry;
> 	}
>
>-- 
>2.31.1
>