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Thu, 21 Nov 2024 10:30:01 -0800 (PST) Sender: Guenter Roeck Date: Thu, 21 Nov 2024 10:30:00 -0800 From: Guenter Roeck To: "Christoph Lameter (Ampere)" Cc: Geert Uytterhoeven , 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: 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=us-ascii Content-Disposition: inline In-Reply-To: <693a6243-b2bd-7f2b-2b69-c7e2308d0f58@gentwo.org> 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. > > 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 ? Guenter