[{"id":35391,"web_url":"https://patchwork.libcamera.org/comment/35391/","msgid":"<20250814013901.GA8360@pendragon.ideasonboard.com>","date":"2025-08-14T01:39:01","subject":"Re: [RFC PATCH v1] libcamera: thread: Use `acquire` memo. when\n\treading event dispatcher","submitter":{"id":2,"url":"https://patchwork.libcamera.org/api/people/2/","name":"Laurent Pinchart","email":"laurent.pinchart@ideasonboard.com"},"content":"Hi Barnabás,\n\nThank you for the patch.\n\nOn Tue, Jan 28, 2025 at 01:03:10PM +0000, Barnabás Pőcze wrote:\n> Use `std::memory_order_acquire` everywhere the dispatcher is loaded\n> to guarantee synchronization with the release-store that places\n> the pointer there.\n> \n> Signed-off-by: Barnabás Pőcze \n\nReviewed-by: Laurent Pinchart \n\n> ---\n> src/libcamera/base/thread.cpp | 4 ++--\n> 1 file changed, 2 insertions(+), 2 deletions(-)\n> \n> diff --git a/src/libcamera/base/thread.cpp b/src/libcamera/base/thread.cpp\n> index 319bfda9a..de60567f6 100644\n> --- a/src/libcamera/base/thread.cpp\n> +++ b/src/libcamera/base/thread.cpp\n> @@ -238,7 +238,7 @@ Thread::Thread()\n> \n> Thread::~Thread()\n> {\n> -\tdelete data_->dispatcher_.load(std::memory_order_relaxed);\n> +\tdelete data_->dispatcher_.load(std::memory_order_acquire);\n> \tdelete data_;\n> }\n> \n> @@ -371,7 +371,7 @@ void Thread::exit(int code)\n> \tdata_->exitCode_ = code;\n> \tdata_->exit_.store(true, std::memory_order_release);\n> \n> -\tEventDispatcher *dispatcher = data_->dispatcher_.load(std::memory_order_relaxed);\n> +\tEventDispatcher *dispatcher = data_->dispatcher_.load(std::memory_order_acquire);\n> \tif (!dispatcher)\n> \t\treturn;\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 35931BDCC1\n\tfor ;\n\tThu, 14 Aug 2025 01:39:24 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 36F3D69251;\n\tThu, 14 Aug 2025 03:39:23 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 0808861436\n\tfor ;\n\tThu, 14 Aug 2025 03:39:21 +0200 (CEST)","from pendragon.ideasonboard.com (81-175-209-231.bb.dnainternet.fi\n\t[81.175.209.231])\n\tby perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id F1B0DAD0;\n\tThu, 14 Aug 2025 03:38:26 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"PDiwDEX5\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1755135507;\n\tbh=HdZ/bj0aU8vMm0hCSnKC5+wqfwcv9clAMetqDYtWCyI=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=PDiwDEX5xUS7BGVZAoLrOPalCKYiDImUjiNSVKwmUmMWu+3EFjDqaJFxBQjygqad5\n\taDs5lRrXCTj2zE5L9I9hfwzvTbv1QcjUVCOm3RPbEDEO0e2HP6TSGKHO527ST7r0yK\n\tem06F4FPiTmrHeXrXWDso137X3Td7F1SxAeN/kCs=","Date":"Thu, 14 Aug 2025 04:39:01 +0300","From":"Laurent Pinchart ","To":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","Cc":"libcamera-devel@lists.libcamera.org","Subject":"Re: [RFC PATCH v1] libcamera: thread: Use `acquire` memo. when\n\treading event dispatcher","Message-ID":"<20250814013901.GA8360@pendragon.ideasonboard.com>","References":"<20250128130308.509297-1-pobrn@protonmail.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=utf-8","Content-Disposition":"inline","Content-Transfer-Encoding":"8bit","In-Reply-To":"<20250128130308.509297-1-pobrn@protonmail.com>","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}}]