From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4F1371AB537; Wed, 31 Jul 2024 10:03:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.187 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722420198; cv=none; b=axJ6q7kffMq4Dn0h3whzinLt7gD8NMWPQuP9HR9+iSEIQiqd6ba3DCaUIE+DBjRU+dzKibSabSb/6qh+06GCkCfHSO9tbtcD06PUeGs8dsqVQVgyI2f9ISuLve6cTFNwv2StPIr+VjCUFSvwKWP73ZFWE7Uc7asUArUr40a+Ao8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722420198; c=relaxed/simple; bh=DukT5UE7XKYXtC2eML+NcnbLOHXSPE0vVMkE58Iu10Q=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=GPOtHgMRixKjJ/w+EGqaFXCH4QyU2h0+e6QeiRqRFuMKLnzcbqKzhcVdxadyiSogF/+0IRcgu5fdnWnAI/VFM+c1fvUUxTFbJ9gQWGI2/PQSbyNGP63ZCRW5tHgbgPLsFYcc1ndGoRq4FtpMqHjeMZ0eHSfRWis9ohjBCHIcJ/8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.162.254]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4WYnbW00MbzyPGX; Wed, 31 Jul 2024 17:58:14 +0800 (CST) Received: from kwepemi100008.china.huawei.com (unknown [7.221.188.57]) by mail.maildlp.com (Postfix) with ESMTPS id 4878B180101; Wed, 31 Jul 2024 18:03:13 +0800 (CST) Received: from [10.67.109.254] (10.67.109.254) by kwepemi100008.china.huawei.com (7.221.188.57) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Wed, 31 Jul 2024 18:03:12 +0800 Message-ID: <034499ea-2cd6-8775-ee94-771cbecd4cdb@huawei.com> Date: Wed, 31 Jul 2024 18:03:11 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.2.0 Subject: Re: [PATCH] ARM: support PREEMPT_DYNAMIC Content-Language: en-US To: "Russell King (Oracle)" CC: , , , , , , , , , , , , References: <20240620090028.729373-1-ruanjinjie@huawei.com> <79a3de7c-21da-12ce-8372-9c9029c237ac@huawei.com> From: Jinjie Ruan In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemi100008.china.huawei.com (7.221.188.57) On 2024/7/31 16:24, Russell King (Oracle) wrote: > On Wed, Jul 31, 2024 at 10:07:53AM +0800, Jinjie Ruan wrote: >>> #ifdef CONFIG_PREEMPTION >>> +#ifdef CONFIG_PREEMPT_DYNAMIC >>> + bl need_irq_preemption >>> + cmp r0, #0 >>> + beq 2f >>> +#endif > > Depending on the interrupt rate, this can be regarded as a fast path, > it would be nice if we could find a way to use static branches in > assembly code. It seems to be hard to use static keys in assembly code. By the way, currently, most architectures have simplified assembly code and implemented its most functions in C functions. Does arm32 have this plan? >