From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id uScoDSVjeGAbdQAAWB0awg (envelope-from ) for ; Thu, 15 Apr 2021 12:00:37 -0400 Received: by simark.ca (Postfix, from userid 112) id 281CF1F104; Thu, 15 Apr 2021 12:00:37 -0400 (EDT) X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-1.1 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.2 Received: from lists.lttng.org (lists.lttng.org [167.114.26.123]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id 9ABCD1E01F for ; Thu, 15 Apr 2021 12:00:36 -0400 (EDT) Received: from lists-lttng01.efficios.com (localhost [IPv6:::1]) by lists.lttng.org (Postfix) with ESMTP id 4FLkZr0Y1Sz1BS8; Thu, 15 Apr 2021 12:00:36 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.lttng.org; s=default; t=1618502436; bh=VKmRhQhFBXNqQhHJPO7JaCVmw36dZPxXe/E6RcVFwVA=; h=Date:To:Cc:In-Reply-To:References:Subject:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From:Reply-To:From; b=jbskeKkiW+qoT716XLT7pfgD9ZVqvMK6zZDslNMYGmhDtmnS/jnViEJBvgcXsoA++ /lZ64uplkJF0GWY2SpLRYmbzirLMjeolOH3F1y51Ux0ZK9IuPvx0iwik61Hl8qI3he nw3iqnLfdMKSpuJEyOjqOrIDQOCw7zdwIuKP+y6AMjgYIDyMo7ucRmd5f52lXqOEtU H4b/ZiA/OQ2M2eFdBXuXZRnxbl+XsAQKvRScYBELzq432o9SvzOjE0/h/Af+No2N3b 4SXspbF7CmIy3z2rC97LQrqMBole6NCRZHVEIyBMcLVjLsp7foWyUWfRxFSG1g5Lgb GLrTDRapRu2og== Received: from mail.efficios.com (mail.efficios.com [167.114.26.124]) by lists.lttng.org (Postfix) with ESMTPS id 4FLkZq3JjZz1BS7 for ; Thu, 15 Apr 2021 12:00:35 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 04BDE32DBCE for ; Thu, 15 Apr 2021 12:00:29 -0400 (EDT) Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id rdHoBcQsgJxC; Thu, 15 Apr 2021 12:00:28 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 9071132DBCD; Thu, 15 Apr 2021 12:00:28 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 9071132DBCD X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id Ndf9cx-mfVEB; Thu, 15 Apr 2021 12:00:28 -0400 (EDT) Received: from mail03.efficios.com (mail03.efficios.com [167.114.26.124]) by mail.efficios.com (Postfix) with ESMTP id 7B8F232D86D; Thu, 15 Apr 2021 12:00:28 -0400 (EDT) Date: Thu, 15 Apr 2021 12:00:28 -0400 (EDT) To: lbj Cc: paulmck , lttng-dev Message-ID: <219280299.78204.1618502428396.JavaMail.zimbra@efficios.com> In-Reply-To: <7E67A2E3-2ABD-430D-8F06-A09A6E69FD8C@yahoo.com> References: <412098958.77686.1618491853089.JavaMail.zimbra@efficios.com> <7E67A2E3-2ABD-430D-8F06-A09A6E69FD8C@yahoo.com> MIME-Version: 1.0 X-Originating-IP: [167.114.26.124] X-Mailer: Zimbra 8.8.15_GA_3996 (ZimbraWebClient - FF87 (Linux)/8.8.15_GA_4007) Thread-Topic: QSBR urcu read lock question Thread-Index: nLQzDa0ilDyo/mKTGWaTlW8XQn2Zvg== Subject: Re: [lttng-dev] QSBR urcu read lock question X-BeenThere: lttng-dev@lists.lttng.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: LTTng development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Mathieu Desnoyers via lttng-dev Reply-To: Mathieu Desnoyers Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" ----- On Apr 15, 2021, at 10:54 AM, lbj lbj137@yahoo.com wrote: > Mathieu, > Thanks so much for your wealth if information and timely responses, they are > greatly appreciated. Final question: is there any harm in explicitly calling > rcu_thread_online/rcu_thread_offline from within my call_rcu callback function? > From what you described it sounds like it would be redundant, but presumably > would be harmless. Correct? Thanks again. You could indeed invoke pairs of: rcu_thread_offline(); <--- emphasis on _offline_ here. [ long wait ... ] rcu_thread_online(); in that specific order within the call-rcu worker thread. Note that the qsbr state of the call-rcu worker thread is "online" when it invokes the callbacks, so each callback should make sure that state is back to "online" before it returns control back to its caller. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev