linux-kernel - Re: [PATCH v7 0/2] MIPS: Fix idle VS timer enqueue

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Message-ID: <aA3n0Cs42R5I9pJ5@alpha.franken.de>
Date: Sun, 27 Apr 2025 10:16:16 +0200
From: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
To: Marco Crivellari <marco.crivellari@...e.com>
Cc: linux-mips@...r.kernel.org, linux-kernel@...r.kernel.org,
	Frederic Weisbecker <frederic@...nel.org>,
	Anna-Maria Behnsen <anna-maria@...utronix.de>,
	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <peterz@...radead.org>,
	Huacai Chen <chenhuacai@...nel.org>,
	"Maciej W . Rozycki" <macro@...am.me.uk>
Subject: Re: [PATCH v7 0/2] MIPS: Fix idle VS timer enqueue

On Thu, Apr 03, 2025 at 06:11:41PM +0200, Marco Crivellari wrote:
> This patch aims to fix idle routine while the CPU receive an interrupt,
> because __r4k_wait() only checks if TIF_NEED_RESCHED is set before
> going to sleep.
> The same behavior has been changed in LoongArch [1].
> 
> Code (cross) compiled successfully and I manage to test it on a VM
> emulating a malta board. I ran QEMU with:
> 
> qemu-system-mips64el -M malta -m 2G -kernel vmlinux -serial stdio -drive \
> file=rootfs.ext2,format=raw -append "rootwait root=/dev/sda" -cpu 5Kc
> 
> rootfs generated using buildroot (malta default configuration).
> 
> - [1] https://github.com/chenhuacai/linux/commit/a8aa673ea46c03b3f62992ffa4ffe810ac84f6e3
> 
> ---
> Changes in v7:
>  - patch 2 to handle __r4k_wait() moved to .cpuidle.text section
>  - removed .noreorder section from __r4k_wait()
>  - idle region of 32-bytes
>  - removed C wrapper r4k_wait() and renamed __r4k_wait() to r4k_wait()
>  - changes discussed in:
>     https://lore.kernel.org/lkml/20250315194002.13778-1-marco.crivellari@suse.com/T/#m07f2568d9099101637063bd057a497ceb846be3d
> 
> Changes in v6:
>  - typo in comment, capitalise sentences and full stops
> 
> Changes in v5:
>  - comment: idle interrupt region, instead of rollback region
> 
> Changes in v4:
>  - comments: 36 byte region
> 
> Changes in v3:
>  - changed "daddiu k0, 1" with PTR_ADDIU k0, 5
>  - replaced CONFIG_CPU_MICROMIPS with 3 _ssnop followed by _ehb
>  - integrated the commit message with explanation about
>    CONFIG_CPU_MICROMIPS replacement
> 
> Changes in v2:
>  - Changes introduced by Huacai:
>     https://lore.kernel.org/linux-mips/20250214105047.150835-1-marco.crivellari@suse.com/T/#m75d9c587829e15e0d7baec13078be4e65c936408
> 
> Marco Crivellari (2):
>   MIPS: Fix idle VS timer enqueue
>   MIPS: Move __r4k_wait() to .cpuidle.text section
> 
>  arch/mips/include/asm/idle.h |  3 +-
>  arch/mips/kernel/genex.S     | 63 +++++++++++++++++++++---------------
>  arch/mips/kernel/idle.c      |  7 ----
>  3 files changed, 38 insertions(+), 35 deletions(-)

series applied to mips-fixes.

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]