From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A431B36D for ; Fri, 24 May 2024 01:11:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.15 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716513073; cv=none; b=b+52HBsGvgbKYASEHxKAP5qsj5Fb5ImoxkuA8abUWaf5M6+629lNPTKvlpkuJmOKVdoz8dtspUVKIDMx8tMMfbNNr4Cnpk1itFWd+psjUR2FWbX/94kPw6F0EhYGRCBfJNhx1cQ8H/aan8JSJz0kLwhFWTfy+Y8oivwjxBlCsjk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716513073; c=relaxed/simple; bh=7eD2UmuhPW/+ApwIW9GMlhMuZIHesbvVW8A7NKI8QOY=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=jF8afSzPkskPTYaVUo1pWu1OnkWBwuaQZqwWuCP2wwtHbNWXDXeseR4eVhF0Syauj0qnPq4W0ZFt7/P7xjpUcXCumZZdZUgHkfXdbnXEjnKWJiY5ba4DgcG2JARpJERQgZEVgGAjohcPQozsFOADQaMO3UT0AaVXwCttV8se5Ms= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=nV1a2LlW; arc=none smtp.client-ip=198.175.65.15 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="nV1a2LlW" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1716513070; x=1748049070; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=7eD2UmuhPW/+ApwIW9GMlhMuZIHesbvVW8A7NKI8QOY=; b=nV1a2LlWGpJYj7L36YCtBK1+fxPjG5U+6d0zdM+CZtndyOwrnn7/VulQ alkpc6BMrEpO607gRzVU5G9yAstkwBnsVVvsZtm+RylxgFWAq+5Svc89h Nkj6jN16Pmf7EuNpGWi2rmZllMZebZTA9DQvmGiPDNcWR0QIhFCuqJJkW 9CexgF3f6iqHIikFqTMRMKbo5b5Jbo8rhdTqCgYnmhhId9JfPk3sM8otm yRg+a4PB/we/Yx2NfVzyLleuN0q8G6py8JCraY2n5WBSPsVizOpLWil+F CYenarS7ImJ5jnuyB+b49fsYZVgnEqNxaQV0+p2zHTwe43B3gfFfW4ly1 A==; X-CSE-ConnectionGUID: n6CurlpvSeS6SzWXDcQOBA== X-CSE-MsgGUID: NXz1JHeVQiigp/KvK30x7A== X-IronPort-AV: E=McAfee;i="6600,9927,11081"; a="16662317" X-IronPort-AV: E=Sophos;i="6.08,184,1712646000"; d="scan'208";a="16662317" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 23 May 2024 18:11:10 -0700 X-CSE-ConnectionGUID: TP+9MNGVSm+rgXGYip3/Yg== X-CSE-MsgGUID: eaiXLBj7TkqBRQcgNjeoGw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,184,1712646000"; d="scan'208";a="65065360" Received: from unknown (HELO [10.239.159.127]) ([10.239.159.127]) by fmviesa001.fm.intel.com with ESMTP; 23 May 2024 18:11:08 -0700 Message-ID: <44d4013d-5c25-40ba-a599-91eee6d50a8c@linux.intel.com> Date: Fri, 24 May 2024 09:09:11 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: baolu.lu@linux.intel.com, David Woodhouse , Joerg Roedel , Will Deacon , Robin Murphy Subject: Re: [PATCH 2/3] iommu/vt-d: Use try_cmpxchg64() in intel_pasid_get_entry() To: Uros Bizjak , iommu@lists.linux.dev, linux-kernel@vger.kernel.org References: <20240522082729.971123-1-ubizjak@gmail.com> <20240522082729.971123-2-ubizjak@gmail.com> Content-Language: en-US From: Baolu Lu In-Reply-To: <20240522082729.971123-2-ubizjak@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 5/22/24 4:26 PM, Uros Bizjak wrote: > Use try_cmpxchg64() instead of cmpxchg64 (*ptr, old, new) != old in > intel_pasid_get_entry(). cmpxchg returns success in ZF flag, so > this change saves a compare after cmpxchg (and related move > instruction in front of cmpxchg). > > Signed-off-by: Uros Bizjak > Cc: David Woodhouse > Cc: Lu Baolu > Cc: Joerg Roedel > Cc: Will Deacon > Cc: Robin Murphy > --- > drivers/iommu/intel/pasid.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) Reviewed-by: Lu Baolu Best regards, baolu