From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 A75AA23AB9D; Sat, 15 Aug 2026 01:05:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786755936; cv=none; b=p9M/a8iP7oZw8ljsn18/Ty/gD95axskKTZA5TdzZo7A7p/j7w6wCt82PBGpzFJZS8eWlJBhqkGAnruCJbYskrs3ijigr5rjE3O5xs5abPzPENIOb/Wv9tH3hLdM29XwIcZP/dkWw8Bvihedh4ZFJwxCY2TLO41fUXSDtt71Q6rc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786755936; c=relaxed/simple; bh=IEvCmi4jX4TOPxqdiJWzdumqiYtVhTarQmIJlSCN1CY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=HJG2P/91kS+dkbdUqfkUzsj3Hdxtd7FGE1PrdQTXnmjqmtEsHiHBBuWDGCYywWdmT7KRv71YRiOYAqZh3wSddEeTzZu8pggwaP/dX6g4R8KU9nSUUhqg6im6O1cisgMonZbr1q5QjqZ0dy6XhXjqHBlcEfYohaOc/pLYaZa7cfo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SwRt3JB7; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SwRt3JB7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A7A31F000E9; Sat, 15 Aug 2026 01:05:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786755935; bh=ropyht7MWTjZXecsTc27JOBIBJy4URexeNyvlMRiWK8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=SwRt3JB7Apro/ALHKcy/mdZPsdHTAl9ipxprZmUEkJIzaxuFxY/EVOdDqKInRflMi c458mHcDAbyk06IUViv4+1oPviYmEW8BNfjpLFqqxGpqYLpfqEJuYVJhWDxA3SoMI2 DbiAi/g+l9TtBypsoylGeNeLdj0WVkp2ywbqzbh2CBmyalOsY5GZ1lKBYtrWNB/osZ qW73yn3CUhnc6o4HQugX20dgxrjiw8rst9xowGlH+IjCGoRVUhwt5QE1hJfQyx5+lE Dpp4wj82WcxsChot1QxQp9khG/ftK0LSwSNvgyZwHXoAiYnwis21iMuHGwiIlAFdsq lIZpfDdIXKFiQ== From: Tejun Heo To: David Vernet , Andrea Righi , Changwoo Min Cc: Peter Zijlstra , Emil Tsalapatis , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org, Tejun Heo Subject: [PATCH 2/3] sched_ext: Drop the stale keep_prev fixup in dispatch_pick() Date: Fri, 14 Aug 2026 15:05:31 -1000 Message-ID: <20260815010532.3663253-3-tj@kernel.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260815010532.3663253-1-tj@kernel.org> References: <20260815010532.3663253-1-tj@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The fixup demoting a keep verdict when @prev is not on ext_sched_class guarded against the rq-level SCX_RQ_BAL_KEEP flag going stale back when balancing and picking were separate operations. The verdict now travels in the return value, created and consumed in one invocation against the @prev it evaluated, and every keep decision tests SCX_TASK_QUEUED under the rq lock, which implies ext_sched_class as a class switch dequeues first. Drop the fixup along with dispatch_core_pick()'s copy. Signed-off-by: Tejun Heo --- kernel/sched/ext/ext.c | 12 ------------ 1 file changed, 12 deletions(-) diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index 4867517b71a4..19db98f0e727 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -3355,11 +3355,6 @@ static enum scx_dsp_verdict dispatch_pick(struct rq *rq, struct rq_flags *rf, kick_sync_wait_bal_cb); } - if (unlikely(verdict == SCX_DSP_PREV && prev->sched_class != &ext_sched_class)) { - WARN_ON_ONCE(scx_enable_state() == SCX_ENABLED); - verdict = SCX_DSP_LOCAL; - } - return verdict; } @@ -3410,13 +3405,6 @@ static enum scx_dsp_verdict dispatch_core_pick(struct rq *rq, struct rq_flags *r if (rq->scx.lock_drop_seq != seq) return SCX_DSP_RETRY; - /* see dispatch_pick() */ - if (unlikely(verdict == SCX_DSP_PREV && - prev->sched_class != &ext_sched_class)) { - WARN_ON_ONCE(scx_enable_state() == SCX_ENABLED); - verdict = SCX_DSP_LOCAL; - } - return verdict; } #else /* CONFIG_SCHED_CORE */ -- 2.55.0