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 6961A1F16B for ; Thu, 3 Jul 2025 14:07:33 +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=1751551653; cv=none; b=ccpVAIzssVqLNlAVfzgjjA5i0QKm7xYD3Wo4gxwXSB5vexDo9atVoLLJQN8B+9h2McNsSwFrNtTYnCRBivh6ui/OCMS9tKWllNeZj73MsQRHDKH6OsPeHj8NhW64VQtSveXTSAzTWqERSflOk0RzWJpFE2Y+85YE0bR3ZpbJ/cg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751551653; c=relaxed/simple; bh=aGQWnq0QCADOSirD4jg6Bw1RAIJiwhztAM0VS25tjiw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=SSge08fIjRJHDKsb4DQ9bYFrafw+ex3nSpUHDX86sbOgP3Z2n+QxwZy6zowkA1u5nDmN93sbh2UDgqzTM5jfJSKH9F24b7YOdmSLu9inUM7WLApvvrX+Ymkhv4CTLFWby0bax9gGFj22zaa8qaPDtv+AGXtCu7vuLcJM10MLJjQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GvfbuRZz; 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="GvfbuRZz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7358EC4CEE3; Thu, 3 Jul 2025 14:07:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751551653; bh=aGQWnq0QCADOSirD4jg6Bw1RAIJiwhztAM0VS25tjiw=; h=From:To:Cc:Subject:Date:From; b=GvfbuRZzCxRSB3obuOFCZE2quIRObLGytbFv6dYkGBo5IQ/JWNx8EnUQCZHB7NxB9 3/LQJLiVO7Kc/k80CbT3rEc+K7Tm9BeWryFuYWiXt7YExOKMTrD8uC3ax+A+48jnew g3QkrNpziYBP35FXyJwVIpzebFASVdVRevDlgD4YpSBSpnNzItlATS5gdO2WjRb0CI TAve5DpVi6Xm0ata7oCZk7qo+Ws9aFE/vO9om1QvqRMbZJafl1thHb4Nq6TuOapJCQ pZRm5Cv62Z5NgyOPJWYgZTlV+dW1It3qxW61ZNrn0NZx+hVMDWVUxxrE1FFrtze+7O Td6fgJcHq/gSQ== From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Oleg Nesterov , Peter Zijlstra , Valentin Schneider , Thomas Gleixner , Michal Hocko , linux-mm@kvack.org, Ingo Molnar , Marcelo Tosatti , Vlastimil Babka , Andrew Morton Subject: [PATCH 0/6 v4] sched/mm: LRU drain flush on nohz_full Date: Thu, 3 Jul 2025 16:07:11 +0200 Message-ID: <20250703140717.25703-1-frederic@kernel.org> X-Mailer: git-send-email 2.48.1 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 v3: * Apply review from Oleg and K Prateek Nayak (handle io_uring kthreads and use guard) * Confine this into a new CONFIG_NO_HZ_FULL_WORK because it is still experimental. git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git task/work-v4 HEAD: 87896fa0dc36b421533c9dc85dd32b61eaff887b Thanks, Frederic --- 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/pagevec.h | 18 ++---------------- include/linux/sched.h | 18 ++++++++++++------ 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 | 26 ++++++++++++++++++++++++++ kernel/sched/sched.h | 1 + kernel/task_work.c | 9 +++++++-- kernel/time/Kconfig | 12 ++++++++++++ mm/swap.c | 30 +++++++++++++++++++++++++++++- 12 files changed, 122 insertions(+), 33 deletions(-)