From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id 56/mJhTQnWQ8XREAWB0awg (envelope-from ) for ; Thu, 29 Jun 2023 14:40:20 -0400 Authentication-Results: simark.ca; dkim=pass (2048-bit key; unprotected) header.d=lists.lttng.org header.i=@lists.lttng.org header.a=rsa-sha256 header.s=default header.b=oi5lU438; dkim-atps=neutral Received: by simark.ca (Postfix, from userid 112) id 8AE8F1E0BB; Thu, 29 Jun 2023 14:40:20 -0400 (EDT) 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)) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id 7FF241E0AC for ; Thu, 29 Jun 2023 14:40:18 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.lttng.org; s=default; t=1688064018; bh=aL8nykeo7/tvu8hUMkrJYYJZk6tXKDhETbf/q+zcaio=; h=Date:To:References:In-Reply-To:Subject:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=oi5lU438HT+rFqMYVqIGalHmVR7igMm/SMyijO8ImmxEZtt4rleCHEw+afda4a54w veEqiPJPAnp9PyE2hLB1R5HncqZiu3qQENTGiLjldCBju2l+sxa24m4GbMqDp86vgd qbthdv4G3AMgm5CY0NL+QirJFTAl28WnArp9DlYEx8bYHsb1EY8psCEdBYHgF9EcQV viXoRC3tqzVJvxZjIQZXWm2gUSLGpmvbjDN2hl0W+3ZDdA58guEHM7fpLeJq+NcpE2 Pk8LXZ2rm4oUtrjM7lL2fyLUFPG0IidfbM4jVwz9+JNWQ1tABoL3OWq3Ir6Zn/xO6C K/Bl1NV2OaCgQ== Received: from lists-lttng01.efficios.com (localhost [IPv6:::1]) by lists.lttng.org (Postfix) with ESMTP id 4QsS1Y6rzCz22Gy; Thu, 29 Jun 2023 14:40:17 -0400 (EDT) Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lists.lttng.org (Postfix) with ESMTPS id 4QsS1X5VfFz22Gx for ; Thu, 29 Jun 2023 14:40:16 -0400 (EDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 826E0615C5; Thu, 29 Jun 2023 18:40:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E653FC433C0; Thu, 29 Jun 2023 18:40:08 +0000 (UTC) Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id 8457ACE04CF; Thu, 29 Jun 2023 11:40:08 -0700 (PDT) Date: Thu, 29 Jun 2023 11:40:08 -0700 To: Olivier Dion Message-ID: <5a440c51-43d3-4be6-ba5a-215c9d3e960f@paulmck-laptop> References: <20230515201718.9809-1-odion@efficios.com> <20230607185359.8125-6-odion@efficios.com> <87bkgyjjsz.fsf@laura> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <87bkgyjjsz.fsf@laura> Subject: Re: [lttng-dev] [PATCH v2 05/12] urcu/uatomic: Add CMM memory model X-BeenThere: lttng-dev@lists.lttng.org X-Mailman-Version: 2.1.39 Precedence: list List-Id: LTTng development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: "Paul E. McKenney via lttng-dev" Reply-To: paulmck@kernel.org Cc: Tony Finch , lttng-dev@lists.lttng.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" On Thu, Jun 29, 2023 at 12:49:00PM -0400, Olivier Dion wrote: > On Wed, 21 Jun 2023, "Paul E. McKenney" wrote: > > On Wed, Jun 07, 2023 at 02:53:52PM -0400, Olivier Dion wrote: > >> -#ifdef __URCU_DEREFERENCE_USE_ATOMIC_CONSUME > >> -# define _rcu_dereference(p) __extension__ ({ \ > >> - __typeof__(__extension__ ({ \ > >> - __typeof__(p) __attribute__((unused)) _________p0 = { 0 }; \ > >> - _________p0; \ > >> - })) _________p1; \ > >> - __atomic_load(&(p), &_________p1, __ATOMIC_CONSUME); \ > > > > There is talk of getting rid of memory_order_consume. But for the moment, > > it is what there is. Another alternative is to use a volatile load, > > similar to old-style CMM_LOAD_SHARED() or in-kernel READ_ONCE(). > > I think we can stick to __ATOMIC_CONSUME for now. Hopefully getting rid > of it means it will be an alias for __ATOMIC_ACQUIRE for ever. That seems emininently reasonable to me! Thanx, Paul _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev