From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DF0FEC4828F for ; Fri, 9 Feb 2024 00:13:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=7ABlxTTmzxSnx3eqTNoT7faY3crTsngsdn5cNMpFSQQ=; b=w5aHpoTNpKFh5E rPoKkTSG9VazKw1GpASe/AIW8zZ6PNJXj64RkLZHFry1kS4a+WMol8DRvfqYEslQKbBa1tgSebCl6 o5anS0umgCyyCZ+ZgNO50lK1p3QWbSXVxdQaqOVmS5ZwbcWtlBJCJpJ1+QhDe8N4ykrnrSKXESVMc TiO3RoIbYcqXjZ4+kWGDO9E55ki9N0aHFshgItv7AdEo8GN3sERfcSbjy8lWAtSdAcfusW6XNwNxE EGeSSauk45N17SgOMH+jiJCJ1RybWK41+R4YM4/iZLEO/kX1iwNFT4jMX3DQ+OlogAox0DDMgnHQE SaCtlPZsn6Ilzf1G8zrg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rYEWT-0000000FeTP-0qTG; Fri, 09 Feb 2024 00:13:41 +0000 Received: from mgamail.intel.com ([192.198.163.14]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rYEWR-0000000FeSh-1f6g for linux-arm-kernel@lists.infradead.org; Fri, 09 Feb 2024 00:13:40 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1707437619; x=1738973619; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=bi/0TOx79W8gC2c7v4EQ3+j3O2OhN2gIGw5Zazdda3Q=; b=lKY+eb6zIKXcf8iS4hvArUizB+kF5tQYUewn0G+lfPVuBpJRXf/QFgS/ Si6GA04E5//+F3fJ6leQxCD7fVce/yk3yjaVD0jAhKQUcXDgXRwuNdMOL gMtbU+91iToy1Vp3Hhh8qaEhl9LDJrF0Qw2/jpuSuuq824ahMuMzh/Y1v /CB6217LeRcDaKNd2WlU4zrae1nEPGxNNoIGvoloHApYXVzBbJ7gh/UDf clCGh5MVvI83Av6rFrcb8C1YwVWzxbX+OPHRRteVWONU/hP4EJU5QnAnX ++aPVlmQHvUBkRoujYRXxULQrjmMNXkfiRzq5jT21d9vtighQqg/TSIc7 Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10978"; a="1501362" X-IronPort-AV: E=Sophos;i="6.05,255,1701158400"; d="scan'208";a="1501362" Received: from orviesa005.jf.intel.com ([10.64.159.145]) by fmvoesa108.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2024 16:13:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.05,255,1701158400"; d="scan'208";a="6432514" Received: from tassilo.jf.intel.com (HELO tassilo) ([10.54.38.190]) by orviesa005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2024 16:13:36 -0800 Date: Thu, 8 Feb 2024 16:13:31 -0800 From: Andi Kleen To: Adrian Hunter Cc: Peter Zijlstra , Ingo Molnar , Mark Rutland , Alexander Shishkin , Heiko Carstens , Thomas Richter , Hendrik Brueckner , Suzuki K Poulose , Mike Leach , James Clark , coresight@lists.linaro.org, linux-arm-kernel@lists.infradead.org, Yicong Yang , Jonathan Cameron , Will Deacon , Arnaldo Carvalho de Melo , Jiri Olsa , Namhyung Kim , Ian Rogers , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Subject: Re: [PATCH V5 01/12] perf/core: Add aux_pause, aux_resume, aux_start_paused Message-ID: References: <20240208113127.22216-1-adrian.hunter@intel.com> <20240208113127.22216-2-adrian.hunter@intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20240208113127.22216-2-adrian.hunter@intel.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240208_161339_500794_0D03D748 X-CRM114-Status: GOOD ( 10.24 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org > +static void __perf_event_aux_pause(struct perf_event *event, bool pause) > +{ > + if (pause) { > + if (!READ_ONCE(event->aux_paused)) { > + WRITE_ONCE(event->aux_paused, 1); > + event->pmu->stop(event, PERF_EF_PAUSE); > + } > + } else { > + if (READ_ONCE(event->aux_paused)) { > + WRITE_ONCE(event->aux_paused, 0); > + event->pmu->start(event, PERF_EF_RESUME); > + } This doesn't look atomic. Either the READ/WRITE once are not needed, or you need an actually atomic construct. > + > + rb = ring_buffer_get(event); > + if (!rb) > + return; > + > + local_irq_save(flags); > + /* Guard against NMI, NMI loses here */ > + if (READ_ONCE(rb->aux_in_pause_resume)) > + goto out_restore; > + WRITE_ONCE(rb->aux_in_pause_resume, 1); > + barrier(); > + __perf_event_aux_pause(event, pause); > + barrier(); > + WRITE_ONCE(rb->aux_in_pause_resume, 0); Dito. -Andi _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel