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Howlett" , Mike Rapoport , Suren Baghdasaryan , Muchun Song , Hao Li , Christoph Lameter , David Rientjes , Pedro Falcato , Jann Horn , Matthew Wilcox , Petr Tesarik , linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com, linux-mm@kvack.org, cgroups@vger.kernel.org Subject: Re: [PATCH] slab: remove the SLUB_DEBUG functionality and config option Message-ID: References: <20260401-b4-are-you-serious-v1-1-dcacda70647d@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260401-b4-are-you-serious-v1-1-dcacda70647d@kernel.org> X-Rspamd-Queue-Id: C1BC4120011 X-Stat-Signature: ucn53g39bby8w87ansq8mmwmaq33j8gy X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1775042112-112737 X-HE-Meta: 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 N1jUXiaR MI6xKOkqnyunDf/3k6rG4tSVFd4k02AIy9UUV0VK2sFrFPkjhftHUayLBnwMiY8cmi8o5DM9HeNWYcnOqdMxAqAq+IwpOEaGSHWwpiXx621b4n6rDY+lCf8NOBo5Shd/ghPOSUz6qO30iUoH6Bf+Cd2JZ3JfuOq9MMmNELaASY0vtQMcnxuvn/ysAksfkfcJ4VdtmJEzxUOuWyoEN9MA1OhItAztbTcbr9LvC0XqClgm1jrUiwiTpcqv71muYmHER5p+lt9UrGbZJTi8C8bWYHmEGTbhtSd7g3M/UdPadfuWtvu6axHja6Zpf88jFc45IyuGWeHbuc7fXWGRHpyLumR98LuPnvGYKsq7N Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Apr 01, 2026 at 12:59:29PM +0200, Vlastimil Babka (SUSE) wrote: > The boot-time enabled per-cache debugging has served us well in the > past, but it's time for it to go, for the following reasons. > > - It's a debugging feature. However, thanks to the advent of LLM-based > reviews, we are not adding bugs to the kernel anymore, so it's > unnecessary now. > > - KASAN is more powerful anyway for the classes of bugs that SLUB_DEBUG > can catch. But I suspect KASAN is likely to be removed soon too, see > above. > > - SLAB never had no such dynamic debugging functionality. With the > introduction of sheaves percpu caching, we have turned SLUB back into > SLAB partially, so this just follows that direction. > > - It's removing ~2500 lines of code and I want to keep my overal > diffstats negative. This adds a nice margin. Honestly you're making me look bad because mine is so 'positive' (I SWEAR IT IS TEST CODE AND COMMENTS) so this turns me against this patch... > > Since the slub kunit test depends on SLUB_DEBUG, remove it too. It's not > a big loss, see the first point above. > > Singed-off-by: Vlastimil Babka (SUSE) > --- > Signed-off-by: Vlastimil Babka (SUSE) ...but because you're removing clearly useless and superceded debug code (I mean hello, we have people using openclaw to automate all this unnecessary kernel dev stuff): Reviewed-by: claude-opus-4-6[1m] Assisted-by: Lorenzo Stokes (as per the register) Cheers, Claude