From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6E1CA1547EE for ; Sun, 9 Feb 2025 22:30:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739140213; cv=none; b=rnWVutDLFmxUXUdWB90IJWOlfF/631dRKDYc75zcRxgqhAk5adel5bR7VmS2Ngo4l1RCloAadbm3k6IXfNaPTNti/YnIyWO1V9ghSLgXBMF6JXrQPR+0Vc/I2g9pxlj068A9azZjAFzEKYhOb/alv7NDp439LlYXKs48WqTbW+4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739140213; c=relaxed/simple; bh=1rNkUd1hCd+4vEvTywqE43/ZrYdxvChv2CgPqlTsF4o=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=cnOTXHzmEGX6bggz0CtBNMhXhqwi2UbWTjrAgCDxmaFZQqgVWbJqDtxOt7e+p7a7hDYLJcae+RO+4Lictgz6wCHNZJMAl8+Dflix1lHmZzg9YY2ayghIG14UkK8fUe38/mC0nPrnVc+YomrLeFVcGUXNCk3pV2Vej1Dz/6TUmUk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KYevvj0X; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KYevvj0X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 98273C4CEDD; Sun, 9 Feb 2025 22:30:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1739140213; bh=1rNkUd1hCd+4vEvTywqE43/ZrYdxvChv2CgPqlTsF4o=; h=From:To:Cc:Subject:Date:From; b=KYevvj0XQZ94iWXrQkZyh0/2bwCrKQ0zHPItVvdNT96mU7Xd6NmVWhHJ84KJrRIxl bdECFdUxa9wuxRwFTl9GvSVbJ+Y+KfHsWGPDwWeUHHO3nID89Uut3eEUDQmi3VJ2fo XVmKEkcZDFMApKR+6W56EmpGw7ae9mk8HNv75DjLYMu/cH4Qr+/8qnV10TEy7PVfXi m6yUHiIo1Fn9VloFQ3mA0kuaxG8ongRV0fcY4YduN1iKnoQIcC7OknrxWF0fY7uQ7/ HT6iM5iYqZ/7hiP6QLd8kLaSNo4sMCpNxnKYeO+IRfpAdAvYw9Jd5hkEVrZ8+ILNrQ o1ylUgvYdYf7A== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Peter Zijlstra , Ingo Molnar , Valentin Schneider , Marcelo Tosatti , Vlastimil Babka , Andrew Morton , Michal Hocko , Thomas Gleixner , Oleg Nesterov , linux-mm@kvack.org Subject: [PATCH 0/6 v2] mm: LRU drain flush on nohz_full Date: Sun, 9 Feb 2025 23:29:58 +0100 Message-ID: <20250209223005.11519-1-frederic@kernel.org> X-Mailer: git-send-email 2.46.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When LRUs are pending, the drain can be triggered remotely, whether the remote CPU is running in userspace in nohz_full mode or not. This kind of noise is expected to be caused by preparatory work before a task runs isolated in userspace. This patchset is a proposal to flush that before the task starts its critical work in userspace. Changes since v1: _ Various task_work improvements (Oleg) _ Remove leftover comment on numa_work (Valentin) _ Add Reviewed-by tag from Valentin _ Use housekeeping_cpu() instead of housekeeping_test_cpu() on fastpath to benefit from static branch (Vlastimil) _ Spare the actual remote LRU drain when the target CPU is nohz_full. It is assumed the LRU drain will happen locally eventually. (Michal) Frederic Weisbecker (6): task_work: Provide means to check if a work is queued sched/fair: Use task_work_queued() on numa_work sched: Use task_work_queued() on cid_work tick/nohz: Move nohz_full related fields out of hot task struct's places sched/isolation: Introduce isolated task work mm: Drain LRUs upon resume to userspace on nohz_full CPUs include/linux/sched.h | 15 +++++++++------ include/linux/sched/isolation.h | 17 +++++++++++++++++ include/linux/swap.h | 1 + include/linux/task_work.h | 12 ++++++++++++ kernel/sched/core.c | 6 ++---- kernel/sched/fair.c | 5 +---- kernel/sched/isolation.c | 34 +++++++++++++++++++++++++++++++++ kernel/sched/sched.h | 1 + kernel/task_work.c | 11 +++++++++-- mm/swap.c | 8 +++++++- 10 files changed, 93 insertions(+), 17 deletions(-) -- 2.46.0