From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f47.google.com (mail-wr1-f47.google.com [209.85.221.47]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2B7551FFC7E for ; Wed, 5 Mar 2025 22:18:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.47 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741213092; cv=none; b=Y4Arl4p2rUfBXw5Py4cXGx/O307W6+4ZA+29//Kw3L5m0Jtf30IUKreEty6rjPg/uytfmdJgQhlV5fnNDT/NG3p3+Ae2qxEC9Sgu3RFkKh2d8Gj64meaKRvdSSCsv2jWg800vDpjYmMceAWq8JRyfP53tvgsKBYHy/18B3yJ45w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741213092; c=relaxed/simple; bh=4cfWO8Yj6d04AnoSQtflHOyvcE27k8sYwQ1CDe3NE5s=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=FDhcVGmbA1MNzCHq6jKdttpaLtAGPiuiapcaX9X2R0roPgWmd8NWh1CS+5LSP8iCzAQoFcfYFzuyv1MUML+S/HrDZkfptH+Gx3LwvH6bAEZDRK6WE0ERushwjABv4S0kPlbLMj5VVBuswBNl3RtSOZtst72GZfoAZNhFatGN/Ho= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=QUUL1H7A; arc=none smtp.client-ip=209.85.221.47 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QUUL1H7A" Received: by mail-wr1-f47.google.com with SMTP id ffacd0b85a97d-390e88caa4dso3739334f8f.1 for ; Wed, 05 Mar 2025 14:18:10 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1741213089; x=1741817889; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=xOZNX3gKnQPew7txKyrctAu7JSbEQnrnprCnUb7aAJg=; b=QUUL1H7ANvW4HVsYMvlD6JILxRsTDbAWRGnIwslvzct/HB1O3gB1hQ6+OEUy+y3MHG E33tJ5thOcw7zpEGH62SKeHhOCxhSZubXTHlwaVp8LplJex28p4eAN1x5AWJZ8aZQ/Vr 6Ou9zm65n77vzirgnGTijDcXt8K4EFOS+/IpeosRoS8xGBWrBaoGns/7S4A7XjKyzvRX XBeRZCZLE6Wpb+EFotRNpMmwSIgtXwcUNYvc65xXG5QxIHL2WXQOsOHnvVrqG4vhSlLC mBzQZzw+uLYu0OTj0SDJywfb1jY5PZagglD1lgsDFisNTM1MBJ/bHGES8VFcxpdGY7aN yknw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1741213089; x=1741817889; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=xOZNX3gKnQPew7txKyrctAu7JSbEQnrnprCnUb7aAJg=; b=k2Wvo4IBYE/R0zFYARpM3ivIVH6lzFCTWxEO4NYp0WHzYoz/bbCjBuW5sSBk5QAlyx 3M9Ll5HlE6AZ6ppB3fsiVtIycjQ57LT7YbAFJyAIKRS06qA79kBYjZr4GgNMvBpgArTv 5hSNddvRKN6rqSut5Z/epqOkyLnWFwxbYFNdkZoWjbEm50Ov4s+98qE5VTKCA7dS8OIw LjlOsJMPMg+o5roE7aLLvFTj07TgZyR3dJIyCPa0ZwzVKnhLyc4JOehb2/CWnWId8ktq GQ2dSRWUhczUL1NGxlDpR02UofU+/Nmz7wlddh9NyxtqXgVOP6wYKpd8q21dnjqZU/kO yzmA== X-Forwarded-Encrypted: i=1; AJvYcCV/xDX3zvPm7KynyyqADyKIznKqaubi+FNJasGxoGqDF7xOtfSOEVND9i5V2ABqBtw9F3OavAAUvlcRR94=@vger.kernel.org X-Gm-Message-State: AOJu0YyFHz9UbrXZH7OtQF0dI7blvYvjiwR7lfiX6gHrDB9GzwPDsYJC FFEeaGpOtFgpl0rOE7P+6BeNQnoauTkNVq+OA8JbVK2VWPQD/RFI X-Gm-Gg: ASbGncsG8WEQNmYOLwQVvUWXbktD52AehRPjt8Hgs9lh5lKvEaFHd20JCKbWVSqiKat oxdYcKiWflmvUFYNRjILNGqxlSwInv65RJMsk66rlNc2yFw/VqQQzqeomL7Oc4dUt77DHLElkcb xJkNATRjT2uVowdc+BLTYvczj5k2yzMBp1XgCR5xgkrjYoXSeB/umm0ZYt497NkN5ryaCXPLU7b rUsJ4I8JfgDC+9vDdj7+FR6h00l6PdhjUjrU2tzxdJykzP4xJzGISGrd1728enP2HsPEVuyyftS fsB5+TWm4gUOJfO2JmaEPKPjfmeRHEcTwAEZmzJOPc8ZepiBkhew64idrcenEp6/a98VkcEE77R zKCafzFE= X-Google-Smtp-Source: AGHT+IEr5nOoTaExHSb8p2vSF/KGydetuYekTDGZJO2SpoBVqouVUnVQTXu1uqYRvCF6pnkyFIDFEw== X-Received: by 2002:a5d:47a5:0:b0:390:e9ea:59a with SMTP id ffacd0b85a97d-3911f72f96dmr3480448f8f.5.1741213088775; Wed, 05 Mar 2025 14:18:08 -0800 (PST) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-390e47b6d31sm22056501f8f.42.2025.03.05.14.18.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Mar 2025 14:18:07 -0800 (PST) Date: Wed, 5 Mar 2025 22:18:06 +0000 From: David Laight To: Uros Bizjak Cc: Linus Torvalds , Borislav Petkov , Dave Hansen , x86@kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Dave Hansen , "H. Peter Anvin" Subject: Re: [PATCH -tip] x86/locking/atomic: Use asm_inline for atomic locking insns Message-ID: <20250305221806.7f25108f@pumpkin> In-Reply-To: References: <20250228123825.2729925-1-ubizjak@gmail.com> <20f1af22-71dc-4d62-9615-03030012222e@intel.com> <20250301123802.GCZ8L_qsv7-WwUwqt5@fat_crate.local> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 5 Mar 2025 20:47:46 +0100 Uros Bizjak wrote: ... > From the compiler POV, now that "lock; " prefix lost its semicolon, > removing LOCK_PREFIX_HERE or using asm_inline would result in exactly > the same code. The problematic 31k code size increase (1.1%) with -O2 > is inevitable either way, if we want to move forward. Have you looked to see where that 31k comes from? The compiler must be very near to inlining something and removing a couple of instructions is making a big difference. It is quite likely that some other change will have the same (or the reverse) effect. David