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 6FF829443 for ; Fri, 27 Sep 2024 23:48:41 +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=1727480921; cv=none; b=fqVRvKHmGCi98jMsgcDedrksiyIz6LDJE6cDOmqavDBcTC7nzWL2oA08nbob6MnV8CzLUCfoSWF/w+ngpQtnZbUvQ7BQvs3MsWP/fXN+ztjuN8a8PsmQ+S9+06eGL1UTdxcHe8dKz/NqhUW1jjGX5fQNSA42GhI5AbdtJP88Xps= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727480921; c=relaxed/simple; bh=a+Rk+PQXrVjXnfbKNLhS+TPJo9auIHLOf14dn7KCPKY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=mt/IrWvRK1myMEUbrkTvovvc8IPqSsSnFYVrk7HH3McNpUrX80c1G6Zsxlki0vcc0G5U9XNnGoPSCc6rg6d4P549tbCFjcIAAxllRca7CoB3TftvdXA6WAYnMUBqcffBx6aC773h/ucrFNoVWm/aVU3+r5mBftZ65QLnFtQScAI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BBXs/mut; 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="BBXs/mut" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA502C4CEC4; Fri, 27 Sep 2024 23:48:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1727480920; bh=a+Rk+PQXrVjXnfbKNLhS+TPJo9auIHLOf14dn7KCPKY=; h=From:To:Cc:Subject:Date:From; b=BBXs/mutAZz7KbWSFqg7bupOQZhvQEbogrXP+va8lhadJnYXymd27X5WxRAUbEu/D 3GF0K3UrW9GuEHH503+mPw6oYr5OSLXbPJg37LiugRhn1CPqnOadCBkhLcDhxtZNXb OIw7l2n5y/sz55LRt9sykSC220ujSgZmvHW2NR0LrfOr3JVHcqRKmq74ITlV3i0no0 UBXhur+Fhqv2aank3yd2qTyDcgwHYkJOW7W58ImdcrkTOx7V3tDLBX+zB+jBzEi+aI DQssfg36tHLVZnIahxzEV1j7tqHxjNr7RZxMSY7b5BQlbLNGOZNBbkomf0qKT4mrC7 AXP6TtJoUpP+g== From: Tejun Heo To: void@manifault.com, peterz@infradead.org, mingo@redhat.com Cc: kernel-team@meta.com, linux-kernel@vger.kernel.org, sched-ext@meta.com Subject: [PATCHSET sched/urgent, sched_ext/for-6.12-fixes] sched/core, sched_ext: Add ENQUEUE_RQ_SELECTED to fix ->select_task_rq() skip detection in sched_ext schedulers Date: Fri, 27 Sep 2024 13:46:10 -1000 Message-ID: <20240927234838.152112-1-tj@kernel.org> X-Mailer: git-send-email 2.46.2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit During ttwu, ->select_task_rq() can be skipped if only one CPU is allowed or migration is disabled. sched_ext schedulers may perform operations such as direct dispatch from ->select_task_rq() path and it is useful for them to know whether ->select_task_rq() was skipped in the ->enqueue_task() path. Currently, sched_ext schedulers are using ENQUEUE_WAKEUP for this purpose and end up assuming incorrectly that ->select_task_rq() was called for tasks that are bound to a single CPU or migration disabled. This patchset adds ENQUEUE_RQ_SELECTED to indicate whether ->select_task_rq() was called to ->enqueue_task() and propagate that to sched_ext schedulers so that they can reliably detect whether ->select_task_rq() was skipped. Peter, please let me know how 0001-0002 should be routed. If they get applied to sched/urgent (when it opens), I'll pull it into sched_ext/for-6.12-fixes and apply 0003 on top. If you'd prefer, I can take all three through sched_ext/for-6.12-fixes too. This patchset contains the following patches: 0001-sched-core-Make-select_task_rq-take-the-pointer-to-w.patch 0002-sched-core-Add-ENQUEUE_RQ_SELECTED-to-indicate-wheth.patch 0003-sched_ext-scx_qmap-Add-and-use-SCX_ENQ_CPU_SELECTED.patch 0001-0002 are sched/core patches to add ENQUEUE_RQ_SELECTED. 0003 makes sched_ext propagate the flag as SCX_ENQ_CPU_SELECTED and fix scx_qmap using the new flag. and can also be found in the following git branch: git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext.git scx-ENQUEUE_RQ_SELECTED diffstat follows. Thanks. kernel/sched/core.c | 21 ++++++++++++++------- kernel/sched/ext.c | 1 + kernel/sched/sched.h | 3 +++ tools/sched_ext/scx_qmap.bpf.c | 4 ++-- 4 files changed, 20 insertions(+), 9 deletions(-) -- tejun