From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from canpmsgout01.his.huawei.com (canpmsgout01.his.huawei.com [113.46.200.216]) (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 33B0C246774 for ; Thu, 3 Sep 2026 01:30:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=113.46.200.216 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788399044; cv=none; b=RJ/ZzGAejH26N9TCUnsTfdOefoTyu9hEuexaD15fpsdcHovC3+QJY/GQF+w9BujUmT1OpDhQf9UhMuh75fpJyAfacG8fW1EdppBhVGG1zA9Z57N6/UJ4OqGHXSfXpOyM8aZzqbIb5PHmoRoAIHOJZSDYKCPhda/IO0VV2h8YSrU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788399044; c=relaxed/simple; bh=aDALWrTBvsy4keS/oqKR9knS4cIztrtG9j+0EXeQLE8=; h=Message-ID:Date:MIME-Version:Subject:From:To:CC:References: In-Reply-To:Content-Type; b=pS4MFM0pNbZrFB1qUX3mYisBMgvsOdnFM3R7Je8uyYtDZHwGzn0X6qLghKdc/EuG1ZZN1rB+EKaARijVdCK+8SJI3t+xW9R2FNmWVn+haKStQJ78DpnnS7lVqliRQTyI/kJrrh54b3cjaYsdmw5wezot3HeujPpT4lupkavFK2U= 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; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b=RdKu/HG3; arc=none smtp.client-ip=113.46.200.216 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=huawei.com header.i=@huawei.com header.b="RdKu/HG3" dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=+ENUVdu9evfizldLInCcVDVO9/Of0750cZbX4S7Tuug=; b=RdKu/HG3L9rawEYtYRkoGKyqOCgk/5NB05U4TgtQuaVcjnLqYDLIS46wNp93iwbv/9EsdbnNR mHaVJR/p1U2aF3lA3JOjr6XR+vGXOITWLsKFSBJEsiHyLjbie95yumvWMs8PQM9gvOg5pYRAy9y 30KpoZszP15eX6aN5XlY2fg= Received: from mail.maildlp.com (unknown [172.19.162.223]) by canpmsgout01.his.huawei.com (SkyGuard) with ESMTPS id 4hb1w241wqz1T4JN; Thu, 3 Sep 2026 09:19:14 +0800 (CST) Received: from kwepemk200008.china.huawei.com (unknown [7.202.194.74]) by mail.maildlp.com (Postfix) with ESMTPS id 1140340561; Thu, 3 Sep 2026 09:30:37 +0800 (CST) Received: from [10.67.109.254] (10.67.109.254) by kwepemk200008.china.huawei.com (7.202.194.74) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.45; Thu, 3 Sep 2026 09:30:36 +0800 Message-ID: <6f4a009f-4261-4cce-88b6-1dec5ecc3a53@huawei.com> Date: Thu, 3 Sep 2026 09:30:35 +0800 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 v2 0/6] sched: dynamic: Simplify PREEMPT_DYNAMIC From: Jinjie Ruan To: Mark Rutland , CC: , , , , , , , , , References: <20260803191731.3244294-1-mark.rutland@arm.com> In-Reply-To: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: kwepems100002.china.huawei.com (7.221.188.206) To kwepemk200008.china.huawei.com (7.202.194.74) 在 2026/8/7 11:11, Jinjie Ruan 写道: > > > 在 2026/8/4 3:17, Mark Rutland 写道: >> All architectures which currently suppoort PREEMPT_DYNAMIC select >> ARCH_HAS_PREEMPT_LAZY. On architectures which select >> ARCH_HAS_PREEMPT_LAZY, it has not been possible to select the NONE and >> VOLUNTARY preemption models since v7.0 due to commit: >> >> 7dadeaa6e851 ("sched: Further restrict the preemption modes") >> >> Hence in practice PREEMPT_DYNAMIC no longer supports the NONE or >> VOLUNTARY preemption models. >> >> This series makes the de-facto situation official by making >> PREEMPT_DYNAMIC depend on ARCH_HAS_PREEMPT_LAZY, and removing redundant >> code. >> >> Since v1, I've had to rebase atop v7.2-rc4 to avoid a conflict with >> commit: >> >> a2c02aa0c6ca ("powerpc: Remove dead non-preemption code") >> >> Given this is now late in the cycle, and given the tip:sched/core branch >> is based on v7.2-rc1, I suspect tip folk might not want to queue this >> now. Please let me know what you'd prefer; I'm happy to rebase and >> resend after v7.3-rc1. >> >> Since v1: >> * Rebase to v7.2-rc4 >> * Apply Revied-by tags. >> * Fix typos in commit messages. >> * Add patch to cleanup accessors (per Shrikanth's comment) >> >> Mark. >> >> Mark Rutland (6): >> sched: dynamic: Make PREEMPT_DYNAMIC depend on ARCH_HAS_PREEMPT_LAZY >> sched: dynamic: Simplify {cond,might}_resched() > > > Hi Mark, > > We also need to update the Doc. > > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -5410,8 +5410,6 @@ Kernel parameters > > preempt= [KNL] > Select preemption mode if you have > CONFIG_PREEMPT_DYNAMIC > - none - Limited to cond_resched() calls > - voluntary - Limited to cond_resched() and > might_sleep() calls > full - Any section that isn't explicitly preempt > disabled > can be preempted anytime. Tasks will > also yield > contended spinlocks (if the critical Hi Mark, What do you think? > section isn't > > Best regards, > Jinjie > >> sched: dynamic: Simplify preempt_schedule{,_notrace}() >> sched: dynamic: Simplify irqentry_exit_cond_resched() >> sched: dynamic: Remove HAVE_PREEMPT_DYNAMIC_{CALL,KEY} >> sched: dynamic: Simplify preempt model accessors >> >> arch/Kconfig | 38 ------- >> arch/arm64/Kconfig | 1 - >> arch/arm64/include/asm/preempt.h | 10 -- >> arch/loongarch/Kconfig | 1 - >> arch/powerpc/Kconfig | 1 - >> arch/riscv/Kconfig | 1 - >> arch/s390/Kconfig | 1 - >> arch/s390/include/asm/preempt.h | 11 -- >> arch/x86/Kconfig | 1 - >> arch/x86/include/asm/preempt.h | 28 ----- >> include/asm-generic/preempt.h | 10 -- >> include/linux/irq-entry-common.h | 17 +-- >> include/linux/kernel.h | 20 ---- >> include/linux/preempt.h | 20 ++-- >> include/linux/sched.h | 31 +----- >> kernel/Kconfig.preempt | 9 +- >> kernel/entry/common.c | 17 +-- >> kernel/sched/core.c | 180 +------------------------------ >> 18 files changed, 23 insertions(+), 374 deletions(-) >> >