From patchwork Thu Jan 16 20:13:20 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 13942199 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 F1EB52361DE; Thu, 16 Jan 2025 20:13:29 +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=1737058410; cv=none; b=G0G3r7CRcNrQNBe8Fdq20fEGfcNkqILH2td+lda+Bmitqmbki7wYnB/bifuYK0J6MdUqeHaPJbqTn7siuOHW4kCqiLg7qbfcrxuCSrQHioYrKa3v6VClUjEQAc825XsWCYgr7ImM2zb41bZ0jd2IX+2BQiOK6NSCKht+ldunECI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1737058410; c=relaxed/simple; bh=UlkuzeoqMzYgR+og5Wa1i/pWnGmyFhloUaxNTrXLAcY=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=idwn1ZPZTjM0AeNKsE8cX4MzekX5o582nv896llAOotnx6Kq9FYuMKtZs56kMzbYDKFMHz7Crb94VSNEV0KQ3qBaPZVIYiS7oL+EdaQzwb/XRmLkYdCEowg+3lq5lL93TFG8tdlpdcaT370fUfvXc4OKuOLz+s7eqgJG9vK82KI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eL1tsiJX; 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="eL1tsiJX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A21C2C4CEDF; Thu, 16 Jan 2025 20:13:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1737058409; bh=UlkuzeoqMzYgR+og5Wa1i/pWnGmyFhloUaxNTrXLAcY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eL1tsiJX0l3qAYVtd8nXR0IM9MDWdFw5QOSYAFEEf+WC23k8BvEjd1SRpS0z48iem OkuuYEQVkqixEgbm/gPsweYCmYAyj/SlchGB+n8X6Lijg6aseLYA36M0dFPp9M5Ws1 eb2BFHVGeijUcQMB+QzhCF3b4YWIJJjJgH65LGTEt65OOJBaDJ2SkLwYNoFlTNDY6x Fy0NJoo5Yxm2in53WPAoaMbngMUknYX3C1cfNsl+eHOkny0+s+yNUpUQPAm8zZjUY0 N74QPWWe7bO8oiENy+bJnJgY0qgwZv7rIYJZ0SNX15A3qfDSyWk2JvJjpdy1DxDw7s s/1BtBeJY170w== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 4CE74CE13C4; Thu, 16 Jan 2025 12:13:29 -0800 (PST) From: "Paul E. McKenney" To: rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, Ankur Arora , "Paul E . McKenney" , Frederic Weisbecker , Sebastian Andrzej Siewior Subject: [PATCH rcu 2/9] rcu: rename PREEMPT_AUTO to PREEMPT_LAZY Date: Thu, 16 Jan 2025 12:13:20 -0800 Message-Id: <20250116201327.3782963-2-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: References: Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Ankur Arora Replace mentions of PREEMPT_AUTO with PREEMPT_LAZY. Also, since PREMPT_LAZY implies PREEMPTION, we can reduce the TASKS_RCU selection criteria from: NEED_TASKS_RCU && (PREEMPTION || PREEMPT_AUTO) to: NEED_TASKS_RCU && PREEMPTION CC: Paul E. McKenney Reviewed-by: Frederic Weisbecker Reviewed-by: Sebastian Andrzej Siewior Signed-off-by: Ankur Arora Signed-off-by: Paul E. McKenney --- include/linux/srcutiny.h | 2 +- kernel/rcu/Kconfig | 2 +- kernel/rcu/srcutiny.c | 14 +++++++------- 3 files changed, 9 insertions(+), 9 deletions(-) diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h index 1321da803274d..31b59b4be2a74 100644 --- a/include/linux/srcutiny.h +++ b/include/linux/srcutiny.h @@ -64,7 +64,7 @@ static inline int __srcu_read_lock(struct srcu_struct *ssp) { int idx; - preempt_disable(); // Needed for PREEMPT_AUTO + preempt_disable(); // Needed for PREEMPT_LAZY idx = ((READ_ONCE(ssp->srcu_idx) + 1) & 0x2) >> 1; WRITE_ONCE(ssp->srcu_lock_nesting[idx], READ_ONCE(ssp->srcu_lock_nesting[idx]) + 1); preempt_enable(); diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig index 2bb22dac3b5a9..582d461c9ab7d 100644 --- a/kernel/rcu/Kconfig +++ b/kernel/rcu/Kconfig @@ -91,7 +91,7 @@ config NEED_TASKS_RCU config TASKS_RCU bool - default NEED_TASKS_RCU && (PREEMPTION || PREEMPT_AUTO) + default NEED_TASKS_RCU && PREEMPTION select IRQ_WORK config FORCE_TASKS_RUDE_RCU diff --git a/kernel/rcu/srcutiny.c b/kernel/rcu/srcutiny.c index 4dcbf8aa80ff7..f688bdad293ed 100644 --- a/kernel/rcu/srcutiny.c +++ b/kernel/rcu/srcutiny.c @@ -98,7 +98,7 @@ void __srcu_read_unlock(struct srcu_struct *ssp, int idx) { int newval; - preempt_disable(); // Needed for PREEMPT_AUTO + preempt_disable(); // Needed for PREEMPT_LAZY newval = READ_ONCE(ssp->srcu_lock_nesting[idx]) - 1; WRITE_ONCE(ssp->srcu_lock_nesting[idx], newval); preempt_enable(); @@ -120,7 +120,7 @@ void srcu_drive_gp(struct work_struct *wp) struct srcu_struct *ssp; ssp = container_of(wp, struct srcu_struct, srcu_work); - preempt_disable(); // Needed for PREEMPT_AUTO + preempt_disable(); // Needed for PREEMPT_LAZY if (ssp->srcu_gp_running || ULONG_CMP_GE(ssp->srcu_idx, READ_ONCE(ssp->srcu_idx_max))) { preempt_enable(); return; /* Already running or nothing to do. */ @@ -138,7 +138,7 @@ void srcu_drive_gp(struct work_struct *wp) WRITE_ONCE(ssp->srcu_gp_waiting, true); /* srcu_read_unlock() wakes! */ preempt_enable(); swait_event_exclusive(ssp->srcu_wq, !READ_ONCE(ssp->srcu_lock_nesting[idx])); - preempt_disable(); // Needed for PREEMPT_AUTO + preempt_disable(); // Needed for PREEMPT_LAZY WRITE_ONCE(ssp->srcu_gp_waiting, false); /* srcu_read_unlock() cheap. */ WRITE_ONCE(ssp->srcu_idx, ssp->srcu_idx + 1); preempt_enable(); @@ -159,7 +159,7 @@ void srcu_drive_gp(struct work_struct *wp) * at interrupt level, but the ->srcu_gp_running checks will * straighten that out. */ - preempt_disable(); // Needed for PREEMPT_AUTO + preempt_disable(); // Needed for PREEMPT_LAZY WRITE_ONCE(ssp->srcu_gp_running, false); idx = ULONG_CMP_LT(ssp->srcu_idx, READ_ONCE(ssp->srcu_idx_max)); preempt_enable(); @@ -172,7 +172,7 @@ static void srcu_gp_start_if_needed(struct srcu_struct *ssp) { unsigned long cookie; - preempt_disable(); // Needed for PREEMPT_AUTO + preempt_disable(); // Needed for PREEMPT_LAZY cookie = get_state_synchronize_srcu(ssp); if (ULONG_CMP_GE(READ_ONCE(ssp->srcu_idx_max), cookie)) { preempt_enable(); @@ -199,7 +199,7 @@ void call_srcu(struct srcu_struct *ssp, struct rcu_head *rhp, rhp->func = func; rhp->next = NULL; - preempt_disable(); // Needed for PREEMPT_AUTO + preempt_disable(); // Needed for PREEMPT_LAZY local_irq_save(flags); *ssp->srcu_cb_tail = rhp; ssp->srcu_cb_tail = &rhp->next; @@ -261,7 +261,7 @@ unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp) { unsigned long ret; - preempt_disable(); // Needed for PREEMPT_AUTO + preempt_disable(); // Needed for PREEMPT_LAZY ret = get_state_synchronize_srcu(ssp); srcu_gp_start_if_needed(ssp); preempt_enable();