From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f169.google.com (mail-pl1-f169.google.com [209.85.214.169]) (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 B582F200A3; Thu, 21 Nov 2024 19:08:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732216136; cv=none; b=QsJg7zXnOXso1ea39217WJd9Z5xKNoI2ltrO9e2jH/9F7VYNy5GXNCCWWxWUh+HlmomM00Isn9WWi8L+tjdZeto/yxTVEcQieGtyf5kByafJds9Ou2vx0yKCrXItNPWdasuXncmybH9PtF8zA3vW6iuKeGoQcennqi4MzqNqlUY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1732216136; c=relaxed/simple; bh=aSnyh00fIsUC5ZDX5nHjI5fGwmj5u7jg46YIvqUp1x8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=o397lgmQK+zTaMGsof+KdU/+2x8RLBWs/mhrOqzvIx5W0O1tnMcYxmAG1xjlrpQfoaG50m+TyB8OztKX3zSIf6DKqsZuR2vCVc7RRm8u1zfw3SNKxdQVKOkc8h6Cz8sB2qv7fP075AjfSv3ZzSP2nmVcggJVvRLys0lIpK5ysGA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=roeck-us.net; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=aKl5eeRb; arc=none smtp.client-ip=209.85.214.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=roeck-us.net 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="aKl5eeRb" Received: by mail-pl1-f169.google.com with SMTP id d9443c01a7336-2126408cf52so10770565ad.1; Thu, 21 Nov 2024 11:08:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1732216134; x=1732820934; darn=vger.kernel.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :from:to:cc:subject:date:message-id:reply-to; bh=nbWq6dIR0dmg1klEoLZJOX63cY+RzZOanD3EV08YCvA=; b=aKl5eeRbqmO1z1/FLAAkQtwcm+i58dZdPqVBzBHgws/Vbsr+qjeBxcG8a2SHW4OAWv C4Q+Hf3wOu6NwAB4XRizSEasLPpiq/dTJYQKf4XvspSJ7SaXlF7Ei/2/5KFtBLTCfYkb v9uflF6x13xalCT/sDpK4mUMA9seCwlImuJDdeb9yKQaKsMUgTRWaF2vIVWh7RKLZJD4 ICN7VNLZN3dqSQ8drxoT6AU4PNXkrr3NKCbtQtGF2lzdI+jiad4TnwON9UZBhAf0m3Js z2l1KlSG6HSHoJ1XstZ45I8y88Tzg2DWIzaZQlavVIL1ylE3qqOler8m/d/g8gWSXoJE YAeQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1732216134; x=1732820934; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:sender :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=nbWq6dIR0dmg1klEoLZJOX63cY+RzZOanD3EV08YCvA=; b=iQS0b9BnPxPgXpgF0SbMjR52wcPxvgCEd0TW8a7FNpV2rIbWU1iC3IcBYUT7GImm4F q2FnAyoVzZJHdlhkfRrxk8wfQCUDQtWdR8brCViJ55teogwxYCziLllWRrJeOB15HtWD klqAwng31e6U+oCvg6s2dN0aSJof+jmGXs4Yeu0LK+hkvlH9G9e/edwUky0iwFuueav+ gbOovsI5BOJ2WY52pWN6V6MgxqdbYLP/JsqzrvsbIQaWVjNNBvbStmJJIoQ80nl0J9zc mpHhLtUht+uDNnumOumLmGuSPDOlp3Ib3A6aC3N9wLYYe5icjYPMdaS2Ls4fr+tCxo6E sIVQ== X-Forwarded-Encrypted: i=1; AJvYcCWSSNEZkuYqoI3A3S3qrPemuRx4BdyKPQoj+5rRMCjU8aZ5B6tEyp244FEXYhQW5+JD7I0BZtSMtUet+g==@vger.kernel.org, AJvYcCWYNX+axLbTyrGE17F3pVIoWrAmzCHpuZjg3MGcXe5bsanRbfVPkpdmXZSs5bcbCNu5DBMK6DrkrDo6XBX6@vger.kernel.org, AJvYcCXQLfw93NuliezF3NymagUKaszP1gwoFgsN3pnGYQvluBNjrJVUuLMEXPuWY6DnSyH4YX0U+qD2wg==@vger.kernel.org X-Gm-Message-State: AOJu0YybDcf5MO8d29edzS3AGkrFfsKBUGZsHyWpDPoDgQzk0Q9gpwds PT97vI3OSgCaZpYh9jmkpe3hLCpiCR/VACGguYwB/E/Y10j4GH7T X-Gm-Gg: ASbGnctWfq92DSOO9kgo34KfOYzC3ImFQKg4KDBjV25eiqxmFIEfUnfnwIw+Ap7Of/L 1YZFasQznQitkprH2Jhmu8UKSCRV3p45ZkNLhFajDKhYehEF7uKrkGB1MJMuzUXMsw9uFzTW8R2 js8eZGIfbmzQH1cV+Hy5USOIol5yRTuUeqXDdpMOiLAGQlVsBpGkG76lG0mMdk9Hk8xxs1CfSPt ivGaN/V+1AePHRvgsdBkOwJjxN1bORh3OseKt8qakRAb6XRpZDna1XWd90kBXk= X-Google-Smtp-Source: AGHT+IFp1nsvaBxxBP2+yKyPHL6/9xKZ1ZMDef8nNNgh7X2q36YFA4vEpFb89L6mjd+kNgwZJ1m9+A== X-Received: by 2002:a17:902:dad1:b0:20c:ee48:94f3 with SMTP id d9443c01a7336-2129f433d4fmr1047445ad.14.1732216133794; Thu, 21 Nov 2024 11:08:53 -0800 (PST) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2129dbf979csm1685255ad.129.2024.11.21.11.08.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 Nov 2024 11:08:52 -0800 (PST) Sender: Guenter Roeck Date: Thu, 21 Nov 2024 11:08:51 -0800 From: Guenter Roeck To: Geert Uytterhoeven Cc: "Christoph Lameter (Ampere)" , Vlastimil Babka , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Jens Axboe , Pavel Begunkov , Mike Rapoport , Christian Brauner , Kees Cook , Jann Horn , linux-mm@kvack.org, io-uring@vger.kernel.org, linux-m68k@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] slab: Fix too strict alignment check in create_cache() Message-ID: <508aa9c4-4176-4336-8948-a31f9791dd39@roeck-us.net> References: <80c767a5d5927c099aea5178fbf2c897b459fa90.1732106544.git.geert@linux-m68k.org> <4f70f8d3-4ba5-43dc-af1c-f8e207d27e9f@suse.cz> <2e704ffc-2e79-27f7-159e-8fe167d5a450@gentwo.org> <693a6243-b2bd-7f2b-2b69-c7e2308d0f58@gentwo.org> Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Thu, Nov 21, 2024 at 07:50:33PM +0100, Geert Uytterhoeven wrote: > On Thu, Nov 21, 2024 at 7:30 PM Guenter Roeck wrote: > > On Thu, Nov 21, 2024 at 09:23:28AM -0800, Christoph Lameter (Ampere) wrote: > > > On Thu, 21 Nov 2024, Geert Uytterhoeven wrote: > > > > Linux has supported m68k since last century. > > > > > > Yeah I fondly remember the 80s where 68K systems were always out of reach > > > for me to have. The dream system that I never could get my hands on. The > > > creme de la creme du jour. I just had to be content with the 6800 and > > > 6502 processors. Then IBM started the sick road down the 8088, 8086 > > > that led from crap to more crap. Sigh. > > > > > > > Any new such assumptions are fixed quickly (at least in the kernel). > > > > If you need a specific alignment, make sure to use __aligned and/or > > > > appropriate padding in structures. > > > > And yes, the compiler knows, and provides __alignof__. > > > > > > > > > How do you deal with torn reads/writes in such a scenario? Is this UP > > > > > only? > > > > > > > > Linux does not support (rate) SMP m68k machines. > > s/rate/rare/ > > > > Ah. Ok that explains it. > > > > > > Do we really need to maintain support for a platform that has been > > > obsolete for decade and does not even support SMP? > > > > Since this keeps coming up, I think there is a much more important > > question to ask: > > > > Do we really need to continue supporting nommu machines ? Is anyone > > but me even boot testing those ? > > Not all m68k platform are nommu. > Yes, I wasn't trying to point to m68k, but to nommu in general. Guenter