From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C9AFB311C01 for ; Mon, 11 Aug 2025 16:02:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754928153; cv=none; b=LZlf1k19NUdMgjraYf/E80A6hRCF53yK5Um7m2jmB1lgrut0b8WguYSUcaxNd6jqYJdEv/iqBpPwpKXSDTBjDGoDfGHXig4gj7h9ajtM7DV6ZOHuftDIEtIJ4+PdKGAGo/digAHxGavdihQyH72VgN63fTh8QGJWh1+XvNBKooQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754928153; c=relaxed/simple; bh=kNLSl65ljpcvx0dl4AnonJBTXcS5M2u0FzI2WwfAp3w=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Q68YGmhTbxdAxWv29miOF9BXN2IWWbfrJeNhcxFBiso+KHDYtBIhMup5vuXlUNI0ZuRtjurEhQBRRq+X/TDRhOvofL4Knp0O8gsIWQxUuoUORKRSHohUqsRZH8OkQLWbvVi91mpMFXHZ+yodRBAANZMn4alhfkdnrap+yIeYBb0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0293A267F; Mon, 11 Aug 2025 09:02:23 -0700 (PDT) Received: from [10.1.28.163] (e137867.arm.com [10.1.28.163]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 271C53F738; Mon, 11 Aug 2025 09:02:26 -0700 (PDT) Message-ID: Date: Mon, 11 Aug 2025 17:02:25 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH -next v7 5/7] arm64: entry: Refactor preempt_schedule_irq() check code To: Jinjie Ruan Cc: catalin.marinas@arm.com, will@kernel.org, oleg@redhat.com, sstabellini@kernel.org, mark.rutland@arm.com, puranjay@kernel.org, broonie@kernel.org, mbenes@suse.cz, ryan.roberts@arm.com, akpm@linux-foundation.org, chenl311@chinatelecom.cn, anshuman.khandual@arm.com, kristina.martsenko@arm.com, liaochang1@huawei.com, ardb@kernel.org, leitao@debian.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, Ada Couprie Diaz References: <20250729015456.3411143-1-ruanjinjie@huawei.com> <20250729015456.3411143-6-ruanjinjie@huawei.com> <44fd646c-4e31-4ca6-9e22-f715ad19e0d7@arm.com> From: Ada Couprie Diaz Content-Language: en-US Organization: Arm Ltd. In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 06/08/2025 07:39, Jinjie Ruan wrote: > On 2025/8/5 23:06, Ada Couprie Diaz wrote: >> Hi Jinjie, >> >> On 29/07/2025 02:54, Jinjie Ruan wrote: >>> ARM64 requires an additional check whether to reschedule on return >>> from interrupt. So add arch_irqentry_exit_need_resched() as the default >>> NOP implementation and hook it up into the need_resched() condition in >>> raw_irqentry_exit_cond_resched(). This allows ARM64 to implement >>> the architecture specific version for switching over to >>> the generic entry code. >>> [...] >> I've had some trouble reviewing this patch : on the one hand because >> I didn't notice `arch_irqentry_exit_need_resched()` was added in >> the common entry code, which is on me ! >> On the other hand, I felt that the patch itself was a bit disconnected : >> we add `arch_irqentry_exit_need_resched()` in the common entry code, >> with a default NOP, but in the same function we add to arm64, >> while mentioning that this is for arm64's additional checks, >> which we only implement in patch 7. > Yes, it does. > >> Would it make sense to move the `arch_irqentry_exit_need_resched()` >> part of the patch to patch 7, so that the introduction and >> arch-specific implementation appear together ? >> To me it seems easier to wrap my head around, as it would look like >> "Move arm64 to generic entry, but it does additional checks : add a new >> arch-specific function controlling re-scheduling, defaulting to true, >> and implement it for arm64". I feel it could help making patch 7's >> commit message clearer as well. >> >> From what I gathered on the archive `arch_irqentry_exit_need_resched()` >> being added here was suggested previously, so others might not have the >> same opinion. > Yes, introduce `arch_irqentry_exit_need_resched()` here may help > understand the patch's refactoring purpose. I can see that as well. I shared my opinion in case it could be useful, but as I mentioned in my reply to the cover : it's not a big issue and I'm happy for `arch_irqentry_exit_need_resched()` to be implemented here if that makes more sense ! >> Maybe improving the commit message and comment for this would be enough >> as well, as per my suggestions above. > Thank you! I'll improve the commit message and comment. > My pleasure ! Ada