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 95CA7F3380B for ; Tue, 17 Mar 2026 08:06:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=cg592/7ax/ai3vj9+LKz1OiWhoFxMvDSIh8YWquZMBA=; b=gt/iia26w+ZXb5oR9pZNLT+AWE /0+jmNCFj/YMT2UsrCW42Xv3wPASB+vninjrLbCyCziqiyEFtsKcpJIA/ynoRbrnNjqMDoijp6UpP MvV5QWKveDYW8JeQ+ucMs5oLtYnOL2bk8jqcXSucncOMeXz36NtE+3uSupSZUFnn1nvyzd2pRXT5y qGTjB596m6AfVUZpK38tJLSmYqETA6OMWA5CyWebW/VdtQwUvIaQD8l0Y2ihVG6U9Pe9zprhlSAFW +Nrqpqbpoinyq1aXiCEKSTu67bgspBHgvqYw7EsxaPMGL5f2BTmGCmr5155P3M3ADkVbBpdz7mFY4 FL65QLNA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1w2PRI-00000005hA2-0zm1; Tue, 17 Mar 2026 08:06:08 +0000 Received: from mgamail.intel.com ([192.198.163.19]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1w2PRF-00000005h9e-3Mxf for linux-arm-kernel@lists.infradead.org; Tue, 17 Mar 2026 08:06:06 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1773734766; x=1805270766; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=iMURNNM9AIH1rsZHJq+NkuOt1cRxxMqU8WKIAQJWBhY=; b=eN/Vw3xFo6L0Ez9LtUIqf1D5kZzucJMPpNuE9c49quSkRiwp3hvUMTkM OQ3Wd+uWy61SaY1m0Z/oHWqI9w2yHilgmMWtssQNnOIUDFq0hpdvmc4a1 U3uiI0wNM8hA2vvvyjaB4DPKHiM4c+ctbAhvax0uL4/0I1ioXL9q4i9Rg vqRz0tPoOKSGsaE8zcZmDt7eWJktHfC5sAHThlm0TQnpOh6ehZEDZQDcz LrGV2cFt495+Ryl4BF109D2BIIAyyzhHkztBK90b4xMBuGJ8dAY3SCuhE E2bbv/nJ3KpFDskz/KdRL/ImefS5EbusHDRdDZkwpAy6PGOT6THx5y2zY g==; X-CSE-ConnectionGUID: hHtTKaudRNKnZ2mpnmuC3w== X-CSE-MsgGUID: FXuiLtvKTw2koDZJNkibbw== X-IronPort-AV: E=McAfee;i="6800,10657,11731"; a="73777645" X-IronPort-AV: E=Sophos;i="6.23,124,1770624000"; d="scan'208";a="73777645" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by fmvoesa113.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Mar 2026 01:06:05 -0700 X-CSE-ConnectionGUID: B6sce5gfS3eYat7KD1IA9A== X-CSE-MsgGUID: 7EgpgieoQr+l3rFUEy13xA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,124,1770624000"; d="scan'208";a="221425403" Received: from abityuts-desk.ger.corp.intel.com (HELO localhost) ([10.245.245.97]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Mar 2026 01:05:58 -0700 Date: Tue, 17 Mar 2026 10:05:55 +0200 From: Andy Shevchenko To: Wolfram Sang Cc: Douglas Anderson , Greg Kroah-Hartman , "Rafael J . Wysocki" , Danilo Krummrich , stable@vger.kernel.org, Andrew Lunn , Daniel Scally , "David S. Miller" , Eric Dumazet , Fabio Estevam , Frank Li , Heikki Krogerus , Heiner Kallweit , Jakub Kicinski , Len Brown , Mark Brown , Paolo Abeni , Pengutronix Kernel Team , Rob Herring , Russell King , Sakari Ailus , Saravana Kannan , Sascha Hauer , devicetree@vger.kernel.org, driver-core@lists.linux.dev, imx@lists.linux.dev, linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH] device property: Make modifications of fwnode "flags" thread safe Message-ID: References: <20260316154159.1.I0a4d03104ecd5103df3d76f66c8d21b1d15a2e38@changeid> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs, Bertel Jungin Aukio 5, 02600 Espoo X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260317_010605_852361_1874F8D7 X-CRM114-Status: GOOD ( 20.60 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Mar 17, 2026 at 10:04:43AM +0200, Andy Shevchenko wrote: > On Tue, Mar 17, 2026 at 08:42:08AM +0100, Wolfram Sang wrote: > > > > > ... this change costs some memory on every system. Maybe it can be > > > > avoided? > > > > > > How much memory does it cost? On most 64-bit architectures is +4 bytes, > > > rarely +0 bytes, on m68k it might be +2bytes. On 32-bit it most likely > > > +0 bytes. I expect that 64-bit machines will cope with this bump. > > > > I am not opposing that the issue should be fixed. If it is not possible > > to take the lock everywhere, this is a proper solution. But if we don't > > have to use more memory, then we could save it. Our new SoC easily has > > 'struct device' in the hundreds. > > What's the alignment for the u8 member in your SoC? 4 bytes or 8 bytes? > (I assume it's 64-bit SoC.) FWIW, with the given change it will be still inside 64-byte data structure which most likely occupies a single cache line (before this patch and after as well). -- With Best Regards, Andy Shevchenko