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From: Roman Gushchin To: Vlastimil Babka Cc: Christoph Lameter , David Rientjes , Joonsoo Kim , Pekka Enberg , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Matthew Wilcox , Linus Torvalds , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Catalin Marinas , Rustam Kovhaev , Andrew Morton Subject: Re: Deprecating and removing SLOB Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=fIlmEvFd; spf=pass (imf03.hostedemail.com: domain of roman.gushchin@linux.dev designates 188.165.223.204 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1667933225; a=rsa-sha256; cv=none; b=ayznWpaAzMcAJVZv9vcPe8GjcxV1eWm8pQUM7tOc42NcfIgDght4HLWAeePLp/WHCophP3 Bckdq3lsZm5M+pqBUhuHc8u9U5dLX9PGHOklsWmYH7MK++8DEOkHi0C/XvB48jkEQy1Q8z be3XcZK7h+9EAUK11jeOcOtXOnxlVJ4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1667933225; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=MrIQ3FtzqufFcsoDNlQ77HxkMw/494S1TkLC77QW0G4=; b=mwH5FGSDSp11Os5imlRIczAA3IAgXCoejfqhM67t8vFJq7vmxdeL9ytXQwQp/VCUqITbaD +JyIPODhPklQlswQMayCVoy/tl6mxyLpf7T07gy/SYOp+FFnxBPAZyfS3rnOOJZs6QLy97 JDAnV9/zvEmn9iurL8OFwF6hn0ezwb4= X-Stat-Signature: 4ofkysn831emaoattufc1oeezxwtz1bq X-Rspamd-Queue-Id: 76CDE20003 Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=fIlmEvFd; spf=pass (imf03.hostedemail.com: domain of roman.gushchin@linux.dev designates 188.165.223.204 as permitted sender) smtp.mailfrom=roman.gushchin@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Rspamd-Server: rspam05 X-Rspam-User: X-HE-Tag: 1667933225-871021 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Nov 08, 2022 at 04:55:29PM +0100, Vlastimil Babka wrote: > Hi, > > as we all know, we currently have three slab allocators. As we discussed at > LPC [1], it is my hope that one of these allocators has a future, and two of > them do not. > > The unsurprising reasons include code maintenance burden, other features > compatible with only a subset of allocators (or more effort spent on the > features), blocking API improvements (more on that below), and my inability > to pronounce SLAB and SLUB in a properly distinguishable way, without > resorting to spelling out the letters. > > I think (but may be proven wrong) that SLOB is the easier target of the two > to be removed, so I'd like to focus on it first. Great! SLOB is not supported by the kernel memory accounting code, so if we'll deprecate SLOB, we can remove all those annoying ifndefs. But I wonder if we can deprecate SLAB too? Or at least use the moment to ask every non-SLUB user on why they can't/don't want to use SLUB. Are there any known advantages of SLAB over SLUB? Also, for memory-constrained users we might want to add some guide on how to configure SLUB to minimize the memory footprint. Thank you! Roman