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 148B6255E47 for ; Tue, 25 Mar 2025 11:33:50 +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=1742902431; cv=none; b=pIzOP+sfxeEEou19d+2EbBZltuqxHjxsqoUOzmMhqdp9HTrc8hJ0Q/hfJgSnBUCCutzkCcYTTCUsgJ/HfqNj1t0jczEKKFVd7iTz6FYrdegpG466aI4XXdwfLPaOrFhaCX7JCCVZcI/fJNF3eEOaJxOh8tj83vAvHDKFlQhzyTQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742902431; c=relaxed/simple; bh=1nvub6VmcPWBU5DeaJMe39ZPNnlVg0YiEQNScqiABx0=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version:Content-Type; b=k1HNBwHLDi3ST4rs8lfMUHnckpQAJ5hyaRcWkMLmDLlYL9cPptzJ+xTypsK0s/j35ffXOiMyvFYR9EdhwSI9RjyhSnI82hO/baMh+BrhTcdzYkEthozzqhk7SqrHBzVS/auptwJPMA1LYepWv0aPYCM2LMaXPF89S2hY/hrTU7A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=JexeCldD; 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="JexeCldD" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6952EC4CEE4; Tue, 25 Mar 2025 11:33:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742902430; bh=1nvub6VmcPWBU5DeaJMe39ZPNnlVg0YiEQNScqiABx0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JexeCldDxkoV5cw07DeplE3CKQOZ7GC6cmgeuehuP5NrJFfWA9uxZde0m0iSzzZQh AOkob+2n3KWqsJsL7LRoo6g4Rj3ztxjdgYXBUBYLxs5nu2ZnFigxySIrcMUXQoJX2J lmTaemmydXrqJLaGQsX4bSJ4U6VB9BLtw+DUNg8uii5iDtTOqcJLAItIduhuwxXgoO p9rgnp0etS9ACOMBexBtIXjJgWf9KVxxMw+DJU+QuamfrqanHfM8AQKLNvQe+DEWqM 7+xKGyub8vGSWW23WnYRfJYPog1fs7Z4fqZ0lgalAgjfx34CdZ/6bVJ3TELaOFDyXY CgNCtgg56HpFw== From: Sasha Levin To: stable@vger.kernel.org Cc: Hagar Hemdan , Sasha Levin Subject: Re: [PATCH 6.6] Revert "sched/core: Reduce cost of sched_move_task when config autogroup" Date: Tue, 25 Mar 2025 07:33:49 -0400 Message-Id: <20250324203640-8a44c31bfa09fb2f@stable.kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250324213706.8335-1-hagarhem@amazon.com> References: Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit [ Sasha's backport helper bot ] Hi, ✅ All tests passed successfully. No issues detected. No action required from the submitter. The upstream commit SHA1 provided is correct: 76f970ce51c80f625eb6ddbb24e9cb51b977b598 WARNING: Author mismatch between patch and upstream commit: Backport author: Hagar Hemdan Commit author: Dietmar Eggemann Status in newer kernel trees: 6.13.y | Not found 6.12.y | Not found Note: The patch differs from the upstream commit: --- 1: 76f970ce51c80 ! 1: 03098b8360be3 Revert "sched/core: Reduce cost of sched_move_task when config autogroup" @@ ## Metadata ## -Author: Dietmar Eggemann +Author: Hagar Hemdan ## Commit message ## Revert "sched/core: Reduce cost of sched_move_task when config autogroup" + commit 76f970ce51c80f625eb6ddbb24e9cb51b977b598 upstream. + This reverts commit eff6c8ce8d4d7faef75f66614dd20bb50595d261. Hazem reported a 30% drop in UnixBench spawn test with commit @@ Commit message Tested-by: Hagar Hemdan Cc: Linus Torvalds Link: https://lore.kernel.org/r/20250314151345.275739-1-dietmar.eggemann@arm.com + [Hagar: clean revert of eff6c8ce8dd7 to make it work on 6.6] + Signed-off-by: Hagar Hemdan ## kernel/sched/core.c ## @@ kernel/sched/core.c: void sched_release_group(struct task_group *tg) @@ kernel/sched/core.c: static struct task_group *sched_get_task_group(struct task_ #ifdef CONFIG_FAIR_GROUP_SCHED if (tsk->sched_class->task_change_group) -@@ kernel/sched/core.c: void sched_move_task(struct task_struct *tsk, bool for_autogroup) +@@ kernel/sched/core.c: void sched_move_task(struct task_struct *tsk) { int queued, running, queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE | DEQUEUE_NOCLOCK; - struct task_group *group; + struct rq_flags rf; struct rq *rq; - CLASS(task_rq_lock, rq_guard)(tsk); - rq = rq_guard.rq; - + rq = task_rq_lock(tsk, &rf); - /* - * Esp. with SCHED_AUTOGROUP enabled it is possible to get superfluous - * group changes. - */ - group = sched_get_task_group(tsk); - if (group == tsk->sched_task_group) -- return; +- goto unlock; - update_rq_clock(rq); - running = task_current_donor(rq, tsk); -@@ kernel/sched/core.c: void sched_move_task(struct task_struct *tsk, bool for_autogroup) + running = task_current(rq, tsk); +@@ kernel/sched/core.c: void sched_move_task(struct task_struct *tsk) if (running) put_prev_task(rq, tsk); - sched_change_group(tsk, group); + sched_change_group(tsk); - if (!for_autogroup) - scx_cgroup_move_task(tsk); + + if (queued) + enqueue_task(rq, tsk, queue_flags); +@@ kernel/sched/core.c: void sched_move_task(struct task_struct *tsk) + resched_curr(rq); + } + +-unlock: + task_rq_unlock(rq, tsk, &rf); + } --- Results of testing on various branches: | Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-6.6.y | Success | Success |