From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 BC6763ABD90 for ; Tue, 2 Jun 2026 09:09:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780391390; cv=none; b=PoScTqL/zC/wvmtn4kY5IEmwxEYOuGQ2sLySY0jMczK+nuj1V4JKcsvYhGoOk6PjzPqXFnHwPlxoNesYrkZplWS+3GPZGDWFZRE2VU9Qbaoj1IhD1w9WEP+UUozOqwUFYJ7X67FSpRpCjWsa+P6FFnLNEwkxWHL4AyyrwbE6v/o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780391390; c=relaxed/simple; bh=IXVO4UOJzgfZJZuUQDDB36hp6i+Z/9jHGpNEhKkcdVg=; h=Date:Message-ID:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=oU92nUdnkcZ77FvIyg57ebOsC5SU1Mz5wCme1nIOFjLewcv5g1ZjmHO+8bEJqAu+yqXRfzl3HiaxwMhYz358Dpy+pgKVfC62kP9SoihGJmxxtVgaOCVG2/9fVcaLH49KU2W97WYoAJntzoL+Q5zSzvdQcXAB3jJvKKl2BHFX0KA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=aVeFKNKL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="aVeFKNKL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E34D1F00893; Tue, 2 Jun 2026 09:09:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780391389; bh=0XVBmz9BHknHzfKuDWPHyxc43ZSAObhCdYfjZB2hI14=; h=Date:From:To:Cc:Subject:References; b=aVeFKNKLAEBJFVz2mTCFs1cpOYEnh9vJI4ePigpdbLyTwVZLz+1DU9CWQ8iWd7/BQ TVE9Vt5xjstiaBJvBznl2nRhYBcrvgwg1Q4RhoIiufDhny/Enb9tB674K1esqFMZTx RBxHNgpHa8ZNVJub6SaYyv+BRBUtr0Xy+yDRrNxFBJqmnT0E8KzK605Yi1bgDpOoEy DUR2J6jh/dxIAH1GueJ8ZZtNFdUVJ/Z/kb4viZuvuejRkjBoIx4oNEMZHav1w8bMoY y3AQazTI0kI3G4jgoHGxLFrEv8X4Ox/xg8f/lJDEMTF1ARecub1dKon8QtPdvCeXN0 ZySAU/7NpliyQ== Date: Tue, 02 Jun 2026 11:09:47 +0200 Message-ID: <20260602090535.564499644@kernel.org> User-Agent: quilt/0.69 From: Thomas Gleixner To: LKML Cc: Mathieu Desnoyers , =?UTF-8?q?Andr=C3=A9=20Almeida?= , Sebastian Andrzej Siewior , Carlos O'Donell , Peter Zijlstra , Florian Weimer , Rich Felker , Torvald Riegel , Darren Hart , Ingo Molnar , Davidlohr Bueso , Arnd Bergmann , "Liam R . Howlett" , Uros Bizjak , =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= , Mark Brown , Richard Weinberger Subject: [patch V5 07/16] x86: Select ARCH_MEMORY_ORDER_TSO References: <20260602084648.462672743@kernel.org> 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=UTF-8 The generic unsafe_atomic_store_release_user() implementation does: if (!IS_ENABLED(CONFIG_ARCH_MEMORY_ORDER_TSO)) smp_mb(); unsafe_put_user(); As x86 implements Total Store Order (TSO) which means stores imply release, select ARCH_MEMORY_ORDER_TSO to avoid the unnecessary smp_mb(). Signed-off-by: Thomas Gleixner Reviewed-by: André Almeida --- V4: Rename it correctly V3: Rename to TOS - Peter V2: New patch --- arch/x86/Kconfig | 1 + 1 file changed, 1 insertion(+) --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -113,6 +113,7 @@ config X86 select ARCH_HAS_ZONE_DMA_SET if EXPERT select ARCH_HAVE_NMI_SAFE_CMPXCHG select ARCH_HAVE_EXTRA_ELF_NOTES + select ARCH_MEMORY_ORDER_TSO select ARCH_MHP_MEMMAP_ON_MEMORY_ENABLE select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI select ARCH_MIGHT_HAVE_PC_PARPORT