From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id qGz5C6MveGDZcAAAWB0awg (envelope-from ) for ; Thu, 15 Apr 2021 08:20:51 -0400 Received: by simark.ca (Postfix, from userid 112) id 23C011F104; Thu, 15 Apr 2021 08:20:51 -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 77A191E01F for ; Thu, 15 Apr 2021 08:20:50 -0400 (EDT) Received: from lists-lttng01.efficios.com (localhost [IPv6:::1]) by lists.lttng.org (Postfix) with ESMTP id 4FLdjF5fdQz19nv; Thu, 15 Apr 2021 08:20:49 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.lttng.org; s=default; t=1618489250; bh=uFCufTGxcDxtbMuHtBpAj/JCqW/lYvVHGEJSXxjMLok=; 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=oYly55h7ML1EMUwWm0m67X5hTLH7ppDbycMxts/4wByTWzWxZQBKA4XhNpKVDA/z6 AmQEYEQDh4GThQUFl9JjPz70FIaKoVCjtIA+FhJh52j+afdem8r5ZkHV1pwGP6gPJw UGhV8n1SFaDhpR4HccohaA2rvHIFR73UQSrS5d2g7u6n4L3cahVpOhV8Yx8x1lDdvW Jo748mbIJZoMhnSbP3cawa9wT0h51qlOIizVcccJkr1MCYuvR045zmhtRk4lSoCLrz VxR37/YgahnCbvX8EqyVpGjNU7VXJnKWNo8CAwhQNXlnGx4qLkYZWX6YQi2IG3Is0i 0dn0srJFJsq7A== Received: from mail.efficios.com (mail.efficios.com [167.114.26.124]) by lists.lttng.org (Postfix) with ESMTPS id 4FLdjF3N3Hz19ns for ; Thu, 15 Apr 2021 08:20:49 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 332C232BFD1 for ; Thu, 15 Apr 2021 08:20:43 -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 q1Y5FoI3HEGT; Thu, 15 Apr 2021 08:20:42 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id A890D32C04F; Thu, 15 Apr 2021 08:20:42 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com A890D32C04F 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 3oCNqJVegseD; Thu, 15 Apr 2021 08:20:42 -0400 (EDT) Received: from mail03.efficios.com (mail03.efficios.com [167.114.26.124]) by mail.efficios.com (Postfix) with ESMTP id 8970F32C04A; Thu, 15 Apr 2021 08:20:42 -0400 (EDT) Date: Thu, 15 Apr 2021 08:20:42 -0400 (EDT) To: lbj , paulmck Cc: lttng-dev Message-ID: <1791312961.77601.1618489242390.JavaMail.zimbra@efficios.com> In-Reply-To: <793BB53F-CE1B-4A8A-8D6D-850C7A144DBB@yahoo.com> References: <1546175211.59087.1617739554450.JavaMail.zimbra@efficios.com> <793BB53F-CE1B-4A8A-8D6D-850C7A144DBB@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: jJYF+3USoCaGg2NPW31xy2ZIDoGpHA== 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 13, 2021, at 11:19 PM, lttng-dev lttng-dev@lists.lttng.org wrote: > Hello all, > > I have two different entities that are both protected by QSBR rcu: a policy and > a hashtable. In the reclamation thread for the policy I would like to take a > read lock so that I can safely iterate through the hashtable. I dont see > anything wrong with this, but I just wanted to make sure it was ok since taking > an rcu read lock in an rcu reclamation thread seems like it may be a bit > suspect. Thanks for any insights, let me know if clarification is needed! When you say "the reclamation thread for the policy", do you refer to a call-rcu worker thread ? Also, you are aware that RCU read-side lock/unlock are effectively no-ops for QSBR rcu, right ? 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