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Wed, 1 Apr 2026 11:08:06 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id Sm16JZb8zGnULwAAD6G6ig (envelope-from ); Wed, 01 Apr 2026 11:08:06 +0000 Date: Wed, 1 Apr 2026 12:08:05 +0100 From: Pedro Falcato To: "Vlastimil Babka (SUSE)" Cc: Andrew Morton , Andrey Ryabinin , David Hildenbrand , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Harry Yoo , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , Suren Baghdasaryan , Muchun Song , Hao Li , Christoph Lameter , David Rientjes , 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-Action: no action X-Rspam-User: X-Rspamd-Queue-Id: 4A89D40006 X-Stat-Signature: j5qe65ey9hycsn11zfojzhr6efqqxuaj X-Rspamd-Server: rspam06 X-HE-Tag: 1775041692-335911 X-HE-Meta: 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 TubZA0ue I/QKNlE+QCJgYFfwaPgdzkh4xD3asjqqmvK2DP2EKO/B/iaJZYzI7pDuXcqdAnyUmVDGJvKIHqUEn98fFqd4rZqQdeafuyDXz5fQGKeh7UEW8AYP1G2WNKUs25nN+PjmQnKx4B4w4MNn/yuA33EyRCOhDNBdRzHTvfml8mzVj5P48ELe9Lx7G0IcjzSOPCc5zFRGImAizIcg5oMBAjMpCnowFT406Ou3hHNP1EaAfhBG3RWmw2A0o+q9E868J628dByAIKPvKASGsC5cVXcAui8DmD5FxFgZ+kA44IHlfxYiWTUygQnfods04PxEp9NGKXTT+kiAkzBv6YKi+foD9YwZlveUWATakrTIPlnqbaRYkvsot3YKnIBgsXw6Uebp2Oiu2ecbCUEKAl8gSKIb9Qzxgxw== 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. > > Since the slub kunit test depends on SLUB_DEBUG, remove it too. It's not > a big loss, see the first point above. Did you check if there's a performance regression with this patch? > > Singed-off-by: Vlastimil Babka (SUSE) > --- > Signed-off-by: Vlastimil Babka (SUSE) LGTM, thanks Signed-off-by: Vlastimil Babka (SUSE) -- Pedro