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 1B67CE571; Tue, 21 Jan 2025 18:01:53 +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=1737482514; cv=none; b=VclRejXs1gKfW6EiKw+U16bMD1aRLDj3a+WGwFMNv4ARLtJ4EXYKlOTN9NZWNsW8rpxAOuC9BZNkQmqRtWZv84pGBfnMrJZ0J06+w9ME+4jNRqhrdHIOZDvbGJuNTVDGg2hnkPBlk7IDW+BYzKzSpAtjhZms7qe6aCnf2FQZvms= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737482514; c=relaxed/simple; bh=GrExYwrFJBnBgbGShjjqvMP1rJw7JucgOhu4vdE9ZPc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sFMw/fAoy/rJ4RHO4CeP9tLarurBdHuEInNsp6TS/ixK+Np5DOlYVgXTwvNI91QTwh4a7SpmDUA/sR8FyGVlvMCvdnHuPzwcrNg75SCRpMjiSdJXx9b1A+lcy4H5Ci6e4SSfPkKUDRJegopbhJa10SHB2d9ka46rtYDJktoIaEs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BkUkHjsk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BkUkHjsk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33019C4CEDF; Tue, 21 Jan 2025 18:01:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1737482513; bh=GrExYwrFJBnBgbGShjjqvMP1rJw7JucgOhu4vdE9ZPc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BkUkHjsksJXL50lR2WHKr8pvaUqN0g6+3pKygytNXaqhzFmn5cyj40Ddq+1HgBZSg krmzmqmE1idSmHt1rK+Pfvp5rtDzBy59P2z90VDayOMPNeqH6GUfkHNS4pqmaSRbxH CXnXA8MaciD1TfVqmz+Ki/06LOBwuOJuv9//BUGo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Henry Huang , Andrea Righi , Tejun Heo , Sasha Levin Subject: [PATCH 6.12 063/122] sched_ext: keep running prev when prev->scx.slice != 0 Date: Tue, 21 Jan 2025 18:51:51 +0100 Message-ID: <20250121174535.422548733@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250121174532.991109301@linuxfoundation.org> References: <20250121174532.991109301@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Henry Huang [ Upstream commit 30dd3b13f9de612ef7328ccffcf1a07d0d40ab51 ] When %SCX_OPS_ENQ_LAST is set and prev->scx.slice != 0, @prev will be dispacthed into the local DSQ in put_prev_task_scx(). However, pick_task_scx() is executed before put_prev_task_scx(), so it will not pick @prev. Set %SCX_RQ_BAL_KEEP in balance_one() to ensure that pick_task_scx() can pick @prev. Signed-off-by: Henry Huang Acked-by: Andrea Righi Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin --- kernel/sched/ext.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index f928a67a07d29..4c4681cb9337b 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -2630,6 +2630,7 @@ static int balance_one(struct rq *rq, struct task_struct *prev) { struct scx_dsp_ctx *dspc = this_cpu_ptr(scx_dsp_ctx); bool prev_on_scx = prev->sched_class == &ext_sched_class; + bool prev_on_rq = prev->scx.flags & SCX_TASK_QUEUED; int nr_loops = SCX_DSP_MAX_LOOPS; lockdep_assert_rq_held(rq); @@ -2662,8 +2663,7 @@ static int balance_one(struct rq *rq, struct task_struct *prev) * See scx_ops_disable_workfn() for the explanation on the * bypassing test. */ - if ((prev->scx.flags & SCX_TASK_QUEUED) && - prev->scx.slice && !scx_rq_bypassing(rq)) { + if (prev_on_rq && prev->scx.slice && !scx_rq_bypassing(rq)) { rq->scx.flags |= SCX_RQ_BAL_KEEP; goto has_tasks; } @@ -2696,6 +2696,10 @@ static int balance_one(struct rq *rq, struct task_struct *prev) flush_dispatch_buf(rq); + if (prev_on_rq && prev->scx.slice) { + rq->scx.flags |= SCX_RQ_BAL_KEEP; + goto has_tasks; + } if (rq->scx.local_dsq.nr) goto has_tasks; if (consume_global_dsq(rq)) @@ -2721,8 +2725,7 @@ static int balance_one(struct rq *rq, struct task_struct *prev) * Didn't find another task to run. Keep running @prev unless * %SCX_OPS_ENQ_LAST is in effect. */ - if ((prev->scx.flags & SCX_TASK_QUEUED) && - (!static_branch_unlikely(&scx_ops_enq_last) || + if (prev_on_rq && (!static_branch_unlikely(&scx_ops_enq_last) || scx_rq_bypassing(rq))) { rq->scx.flags |= SCX_RQ_BAL_KEEP; goto has_tasks; -- 2.39.5