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 E1A3A29E0E7; Sat, 20 Sep 2025 00:59:55 +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=1758329996; cv=none; b=X/NyODdSOmJb4dkqicyAfEPVy4sbhI9pUrZxv41XkFlib5Hnu35zxG2GzwcLVbKW9RKfyEC/DXyDHB0WCjm9PgnnWCS/uRVz+t1dwUwOQNBzc0ua3ovnYDdE9wWhWUEiZv9aCK+TRB5yAzaTRiB/uUeCGLSd2MFTVmTzbR/Xhww= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758329996; c=relaxed/simple; bh=7sQ1fkcc+qgQeE3eG8/hVzks21NicPfu4GUI9mIepjg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MeHs9HsiMdvnU5kEk4ChP7zIZtIvvCh8rkRJMUdixqh1y5p8I/af3YjVoQeNA4w4HCBAuSZzpFY1hIyDM9dv4uZ0FwMGdvJKvF3f2F9DLf1ZWHXUGF33DFnV0QXGGirOw6IZbAUbL7nw5ptrySPcW4F+xH8F6z5YGLzYiPlJVSs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mCl9dVrH; 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="mCl9dVrH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A7B57C4CEF0; Sat, 20 Sep 2025 00:59:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1758329995; bh=7sQ1fkcc+qgQeE3eG8/hVzks21NicPfu4GUI9mIepjg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mCl9dVrHknEABH+oTYymPBHB+7GkmS8sigrVSTEONAKkStfk29S1LZU5LWAJeYh7u 2Zar6SIIqWn0//5OsKh6VosLOt0gnNX5hKMPRa3ij+nI14OYbqy595YoqCo3KhrmpC 1xVQxEwZ507erjUrPEiyUOX5VoNe2GPJNc5EKyqm3X3/wRHWf7nFX8ZOQncUgq4tSY NwpOSdAO4rxOEJe3j5yk2CcNQLYBRPpcLTGvBnaN9DmgD+Pe3Wo/qPVZdoZhxUChIv eh2ImvJvu98D3TOapzEBkqHz94ZKHv6DQW/+M7NjbKHfHSmG/zXXYjWQHqTz8UjcOZ 6p0U+7rSQTukA== From: Tejun Heo To: void@manifault.com, arighi@nvidia.com, multics69@gmail.com Cc: linux-kernel@vger.kernel.org, sched-ext@lists.linux.dev, memxor@gmail.com, bpf@vger.kernel.org, Tejun Heo Subject: [PATCH 21/46] sched_ext: Minor reorganization of enable/disable path Date: Fri, 19 Sep 2025 14:58:44 -1000 Message-ID: <20250920005931.2753828-22-tj@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20250920005931.2753828-1-tj@kernel.org> References: <20250920005931.2753828-1-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 - Separate out scx_root_disable() from scx_disable_workfn(). - Rename scx_enable() to scx_root_enable(). - Add @sch to scx_disable(). The callers are now responsible for providing the scx_sched to disable. No functional changes. Signed-off-by: Tejun Heo --- kernel/sched/ext.c | 70 ++++++++++++++++++++++++++-------------------- 1 file changed, 40 insertions(+), 30 deletions(-) diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 0ee716ff4dab..54f65a196d94 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -3018,8 +3018,8 @@ void sched_ext_free(struct task_struct *p) spin_unlock_irqrestore(&scx_tasks_lock, flags); /* - * @p is off scx_tasks and wholly ours. scx_enable()'s READY -> ENABLED - * transitions can't race us. Disable ops for @p. + * @p is off scx_tasks and wholly ours. scx_root_enable()'s READY -> + * ENABLED transitions can't race us. Disable ops for @p. */ if (scx_get_task_state(p) != SCX_TASK_NONE) { struct rq_flags rf; @@ -3933,24 +3933,12 @@ static const char *scx_exit_reason(enum scx_exit_kind kind) } } -static void scx_disable_workfn(struct kthread_work *work) +static void scx_root_disable(struct scx_sched *sch) { - struct scx_sched *sch = container_of(work, struct scx_sched, disable_work); struct scx_exit_info *ei = sch->exit_info; struct scx_task_iter sti; struct task_struct *p; - int kind, cpu; - - kind = atomic_read(&sch->exit_kind); - while (true) { - if (kind == SCX_EXIT_DONE) /* already disabled? */ - return; - WARN_ON_ONCE(kind == SCX_EXIT_NONE); - if (atomic_try_cmpxchg(&sch->exit_kind, &kind, SCX_EXIT_DONE)) - break; - } - ei->kind = kind; - ei->reason = scx_exit_reason(ei->kind); + int cpu; /* guarantee forward progress by bypassing scx_ops */ scx_bypass(true); @@ -4078,21 +4066,35 @@ static void scx_disable_workfn(struct kthread_work *work) scx_bypass(false); } -static void scx_disable(enum scx_exit_kind kind) +static void scx_disable_workfn(struct kthread_work *work) +{ + struct scx_sched *sch = container_of(work, struct scx_sched, disable_work); + struct scx_exit_info *ei = sch->exit_info; + int kind; + + kind = atomic_read(&sch->exit_kind); + while (true) { + if (kind == SCX_EXIT_DONE) /* already disabled? */ + return; + WARN_ON_ONCE(kind == SCX_EXIT_NONE); + if (atomic_try_cmpxchg(&sch->exit_kind, &kind, SCX_EXIT_DONE)) + break; + } + ei->kind = kind; + ei->reason = scx_exit_reason(ei->kind); + + scx_root_disable(sch); +} + +static void scx_disable(struct scx_sched *sch, enum scx_exit_kind kind) { int none = SCX_EXIT_NONE; - struct scx_sched *sch; if (WARN_ON_ONCE(kind == SCX_EXIT_NONE || kind == SCX_EXIT_DONE)) kind = SCX_EXIT_ERROR; - rcu_read_lock(); - sch = rcu_dereference(scx_root); - if (sch) { - atomic_try_cmpxchg(&sch->exit_kind, &none, kind); - kthread_queue_work(sch->helper, &sch->disable_work); - } - rcu_read_unlock(); + atomic_try_cmpxchg(&sch->exit_kind, &none, kind); + kthread_queue_work(sch->helper, &sch->disable_work); } static void dump_newline(struct seq_buf *s) @@ -4558,7 +4560,7 @@ static int validate_ops(struct scx_sched *sch, const struct sched_ext_ops *ops) return 0; } -static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) +static int scx_root_enable(struct sched_ext_ops *ops, struct bpf_link *link) { struct scx_sched *sch; struct scx_task_iter sti; @@ -4808,7 +4810,7 @@ static int scx_enable(struct sched_ext_ops *ops, struct bpf_link *link) * Flush scx_disable_work to ensure that error is reported before init * completion. sch's base reference will be put by bpf_scx_unreg(). */ - scx_error(sch, "scx_enable() failed (%d)", ret); + scx_error(sch, "scx_root_enable() failed (%d)", ret); kthread_flush_work(&sch->disable_work); return 0; } @@ -4940,7 +4942,7 @@ static int bpf_scx_check_member(const struct btf_type *t, static int bpf_scx_reg(void *kdata, struct bpf_link *link) { - return scx_enable(kdata, link); + return scx_root_enable(kdata, link); } static void bpf_scx_unreg(void *kdata, struct bpf_link *link) @@ -4948,7 +4950,7 @@ static void bpf_scx_unreg(void *kdata, struct bpf_link *link) struct sched_ext_ops *ops = kdata; struct scx_sched *sch = ops->priv; - scx_disable(SCX_EXIT_UNREG); + scx_disable(sch, SCX_EXIT_UNREG); kthread_flush_work(&sch->disable_work); kobject_put(&sch->kobj); } @@ -5074,7 +5076,15 @@ static struct bpf_struct_ops bpf_sched_ext_ops = { static void sysrq_handle_sched_ext_reset(u8 key) { - scx_disable(SCX_EXIT_SYSRQ); + struct scx_sched *sch; + + rcu_read_lock(); + sch = rcu_dereference(scx_root); + if (likely(sch)) + scx_disable(sch, SCX_EXIT_SYSRQ); + else + pr_info("sched_ext: BPF schedulers not loaded\n"); + rcu_read_unlock(); } static const struct sysrq_key_op sysrq_sched_ext_reset_op = { -- 2.51.0