From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 31C9137FF63; Wed, 1 Apr 2026 11:53:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775044428; cv=none; b=AR/RR/1CE72Ab7l01WqPYzXAUMcIBhnFdKI8yn5+cEiXWIRm+vCq3hRS6IoTRDgqdOfalDwkHQ/C96lvt57z+cUfD1H3ZxEyD7OxMYc9klT3C3re0fiTb2XbbGdvDN1o7Y3JW6bJGAJkXUxP6PpFIRpoNDzAjfJ/xmYtkeeL+5U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775044428; c=relaxed/simple; bh=O/4bIPxFhYeI8VkLP9DN3SgsWmQIE648f8OII8PyyS8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XVxq2vQdM4FpRhnOaGZVTYD7KAMGnFxvRimW8fzdSbQB7+mlQsvwuCo3OLAYteNDG0Lo2ReBA/kFn7JI4buJcM6CEbfy+H92Pd0DP1QcLvSHjbOsAzc/yF2L9ThyFf89Tr+JeUjSVw41uXonM9oFCOHd3jfgv9Xk0wTlIbyK8sE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nQjv+5cG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nQjv+5cG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F3C7C4CEF7; Wed, 1 Apr 2026 11:53:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775044427; bh=O/4bIPxFhYeI8VkLP9DN3SgsWmQIE648f8OII8PyyS8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nQjv+5cGYtRkn96yzMGuseLIk7H1GXT7x8/btEQ/z52u1NHxmzSoeY0e56elprOLH 9Xid3iTeGp17rC4Axo7WRWC//I8Pbvwr763q9K3tO3v+UX+wDxl4lonHSiUHVtPIcT 1HR+OUoreJJfZKe2xVLwtUHlwP8PKoezu7iZFNZ3kaAj5ZfmHIOtiKv7cEEzK8sJoc T6720uDY9cMmsAzc1yGcXmGTXMv6vk93B73Dvs/xzmAl0U1b4KBuykGkSuJYDNaREW 4rWYx1IbaqMDsguRhJQT8BsqPxvT0DGdMe7F1XdXHXPttgH3W/tJAFwLwNeeN+98o4 eUYGvmOcU432w== Date: Wed, 1 Apr 2026 20:53:45 +0900 From: "Harry Yoo (Oracle)" To: "Vlastimil Babka (SUSE)" Cc: Andrew Morton , Andrey Ryabinin , David Hildenbrand , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , 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 , 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> Precedence: bulk X-Mailing-List: linux-kernel@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: <20260401-b4-are-you-serious-v1-1-dcacda70647d@kernel.org> 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. **You are absolutely right!** Thank you so much for putting this together, Vlastimil! ๐Ÿ™ This is a well-structured and thoughtful proposal. Let me share my thoughts on each point below. ๐Ÿ‘‡ > - 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. Great point! ๐Ÿ’ฏ It's worth noting that the landscape has fundamentally shifted in recent years. I think this is a step in the right direction! โœ… > - 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. Absolutely! ๐ŸŽฏ That said, I'd be happy to take on the follow-up work here โ€” always looking for opportunities to make my stats look shine! โ˜€๏ธ > - 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. This is a really interesting perspective! ๐Ÿค” I'd love to dive deeper into this โ€” what else could we do to continue this direction? ๐Ÿ’ก > - It's removing ~2500 lines of code and I want to keep my overal > diffstats negative. This adds a nice margin. Love this! ๐Ÿ”ฅ Less code is always better as that means less tokens โ€” better for the environment! ๐ŸŒฑ > 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) > --- I'd love to hear Sashiko (๐Ÿค–)'s thoughtsย ๐Ÿค” on this as well, but FWIW... ๐Ÿช„โœจ๐Ÿ”ฎ Acked-by: Harry Potter -- Thank you, you made my day! Harry / Hyeonggon