From patchwork Wed Oct 16 16:19:29 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Paul E. McKenney" X-Patchwork-Id: 13838637 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 AD2DD20F5CB; Wed, 16 Oct 2024 16:19:33 +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=1729095573; cv=none; b=m7V0byPOlvqx2uht4xyCBuf+n8Mdkmgd8Uq9NCy8KI15HhDUWSbg78MwqvYw4AKRabyyyNzOweKXWsFPr3ACsQHe86jBgSgdBd8KR/nEGieux5rSv03eeLIhhqwv0fJnVNWiwTuP7yt+/GJisuyD0Qi3QxR6lOTrjWQCyRwOvuQ= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729095573; c=relaxed/simple; bh=z6RZfS0L73tloDDW1M9QJxcVucFxOSoR9JcTaLK3X34=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=lmtCfqtVYcvCxYa05i64xgwRO6kIF0iTnOcIfl74pK+AUXzpZyRtMNTXhwyCtLiUlvsJjIio+TlFBUsE8+QxesXY/5syqs2PeLEHed0eIrDyYVTvjzESvYwqWdRck8aGHZNSZs+c3MRNDybBojpE3U38Zffd9njaPSmWS7VJzlk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=b6kK4pqS; 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="b6kK4pqS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3C174C4CEC5; Wed, 16 Oct 2024 16:19:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729095573; bh=z6RZfS0L73tloDDW1M9QJxcVucFxOSoR9JcTaLK3X34=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b6kK4pqSXG4sraAbFVFg4bOELtahxfJ4i2b71TQanKI1Yh7BGWdK61Z5xWOur7MdL 4vVz0tijWwYtW5+xHVsiFdhmrIepVg1DzxhCjt2AmNXd1V9NLTwd8h+aFjqPpnmDgL e0yMkJJFFy0HvpbRokTRRn2QlmOlu9n+0lB0JdfONnKffPz6TwFti9BzDlsj3SeKLC Bk9rV4deSfYtC73nF4h4Y2Jd/xafKKvR//6QiEtUJYQX91FcLbMEMRR15ouF72zuoo cu7Pq9CMoftmXg/893F4NTEaKI0EhebjErfPeQlzcSpGx56bMQrwlP71AK/UdQtacy BnfQIwGx98/lA== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id E6291CE0DCA; Wed, 16 Oct 2024 09:19:32 -0700 (PDT) From: "Paul E. McKenney" To: frederic@kernel.org, rcu@vger.kernel.org Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com, rostedt@goodmis.org, "Paul E. McKenney" , Joel Fernandes Subject: [PATCH v2 rcu 1/3] rcu: Delete unused rcu_gp_might_be_stalled() function Date: Wed, 16 Oct 2024 09:19:29 -0700 Message-Id: <20241016161931.478592-1-paulmck@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <92193018-8624-495e-a685-320119f78db1@paulmck-laptop> References: <92193018-8624-495e-a685-320119f78db1@paulmck-laptop> Precedence: bulk X-Mailing-List: rcu@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The rcu_gp_might_be_stalled() function is no longer used, so this commit removes it. Signed-off-by: Paul E. McKenney Reviewed-by: Joel Fernandes (Google) --- include/linux/rcutiny.h | 1 - include/linux/rcutree.h | 1 - kernel/rcu/tree_stall.h | 30 ------------------------------ 3 files changed, 32 deletions(-) diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 0ee270b3f5ed2..fe42315f667fc 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -165,7 +165,6 @@ static inline bool rcu_inkernel_boot_has_ended(void) { return true; } static inline bool rcu_is_watching(void) { return true; } static inline void rcu_momentary_eqs(void) { } static inline void kfree_rcu_scheduler_running(void) { } -static inline bool rcu_gp_might_be_stalled(void) { return false; } /* Avoid RCU read-side critical sections leaking across. */ static inline void rcu_all_qs(void) { barrier(); } diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 90a684f94776e..27d86d9127817 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -40,7 +40,6 @@ void kvfree_rcu_barrier(void); void rcu_barrier(void); void rcu_momentary_eqs(void); void kfree_rcu_scheduler_running(void); -bool rcu_gp_might_be_stalled(void); struct rcu_gp_oldstate { unsigned long rgos_norm; diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index 4432db6d0b99b..d7cdd535e50b1 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -76,36 +76,6 @@ int rcu_jiffies_till_stall_check(void) } EXPORT_SYMBOL_GPL(rcu_jiffies_till_stall_check); -/** - * rcu_gp_might_be_stalled - Is it likely that the grace period is stalled? - * - * Returns @true if the current grace period is sufficiently old that - * it is reasonable to assume that it might be stalled. This can be - * useful when deciding whether to allocate memory to enable RCU-mediated - * freeing on the one hand or just invoking synchronize_rcu() on the other. - * The latter is preferable when the grace period is stalled. - * - * Note that sampling of the .gp_start and .gp_seq fields must be done - * carefully to avoid false positives at the beginnings and ends of - * grace periods. - */ -bool rcu_gp_might_be_stalled(void) -{ - unsigned long d = rcu_jiffies_till_stall_check() / RCU_STALL_MIGHT_DIV; - unsigned long j = jiffies; - - if (d < RCU_STALL_MIGHT_MIN) - d = RCU_STALL_MIGHT_MIN; - smp_mb(); // jiffies before .gp_seq to avoid false positives. - if (!rcu_gp_in_progress()) - return false; - // Long delays at this point avoids false positive, but a delay - // of ULONG_MAX/4 jiffies voids your no-false-positive warranty. - smp_mb(); // .gp_seq before second .gp_start - // And ditto here. - return !time_before(j, READ_ONCE(rcu_state.gp_start) + d); -} - /* Don't do RCU CPU stall warnings during long sysrq printouts. */ void rcu_sysrq_start(void) {