From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id ED4BCC43458 for ; Tue, 30 Jun 2026 02:03:19 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D5D946B00B5; Mon, 29 Jun 2026 22:03:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D347C6B00B6; Mon, 29 Jun 2026 22:03:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C25EC6B00B7; Mon, 29 Jun 2026 22:03:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 987556B00B5 for ; Mon, 29 Jun 2026 22:03:18 -0400 (EDT) Received: from smtpin24.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 190BB8D22F for ; Tue, 30 Jun 2026 02:03:18 +0000 (UTC) X-FDA: 84934931676.24.CD878B6 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf14.hostedemail.com (Postfix) with ESMTP id 70194100002 for ; Tue, 30 Jun 2026 02:03:16 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=JB67cFz1; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf14.hostedemail.com: domain of harry@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=harry@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1782784996; b=0Kty3BaI0e5qALEVMDZXP0jB9N4jHIqIceheFQe/uo7y5IvHfA4Bz9DzVq7SLBVlaoz+vr wR7138k8ltO7LIVrQpTVmWzyBQqNtZG7R/M64OJXktphlRlAYkgdzXG7dd2FVoU/k2AFSU 2LrWwJQXj6XvkE1ChTW4zMK2mTlHV/w= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1782784996; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=Mh7wOyZn2mNMutLQV04yehx/G0sNH7B0Hew764ZGcLo=; b=dG6MeCB/AlHBOT1LszKb+gegwlzfvbBhIr9i8lzILcbpRY60eEhwKCKjH3knPlKvEfgRLN wmtLha0VBG/04VOskdTzexoSgcy1ulDew5XnwQNrGQ0YX4xbXHitePihqQ8kQX0Flf+av1 vve17L6bTCnr507Zx4aMGTxiRyWMPUQ= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=JB67cFz1; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf14.hostedemail.com: domain of harry@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=harry@kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id DD17F600BB; Tue, 30 Jun 2026 02:03:15 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C18461F000E9; Tue, 30 Jun 2026 02:03:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782784995; bh=Mh7wOyZn2mNMutLQV04yehx/G0sNH7B0Hew764ZGcLo=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=JB67cFz1Eh2BdtYGo48IZqLlyadmM5XzhgRACvMfyawWgPNoYxUHyrZy5U9qvgJWi JDCxVqtXhhj/3rGgcWOlYxodxD/oGy9i/fHg6legClp2Ygb7fjhz+l84Ecz0/Sc3MX dvocMWlQ3yLz6SWHtuNDCH9d7zateJBMlxyccULPWLKp0unyu5DGjtsY7kDyk9Fx8Q ql36xS8xTsif8z3MUyDP9o5J3ClXX31dGr2CYylHkVO8n3V1jRSpCfLNhIntXt3TLY HHTzBoPCTak0Ohj39z4YgccsnA/nZpskQIWEHaxCb/4C/cVG2Pq//iUkYMoazNaRX1 MEe4aRGsAkfqA== Message-ID: <393141e3-589d-46d0-90a6-88b9129ae67e@kernel.org> Date: Tue, 30 Jun 2026 11:03:11 +0900 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm/slub: serve slabobj_ext array from a strictly larger kmalloc cache To: Shakeel Butt , Suren Baghdasaryan Cc: "Vlastimil Babka (SUSE)" , Andrew Morton , Roman Gushchin , Hao Li , Christoph Lameter , David Rientjes , Usama Arif , Meta kernel team , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Danielle Costantino , Kees Cook References: <62453403-954c-4cf1-8924-6d38184b0810@kernel.org> <09267187-6c85-438f-8791-4cce8d07892a@kernel.org> <68122038-e8e0-47ed-82f8-cb6a23e4658e@kernel.org> Content-Language: en-US From: Harry Yoo In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 70194100002 X-Rspam-User: X-Stat-Signature: jjszunjte3tr39g7taid3nfk8gg546in X-HE-Tag: 1782784996-204868 X-HE-Meta: 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 dUVaQl5+ /IdTvJ3Xd8RXgnV08wv+29s9xSXL6Lfe6AubJMdjoVYW8G7cA8mdWfSTBc8lEGuRUOzUxPn5n7sKKcXKj8oWk5m87aVNyh60BrRGKxhDRmeSzRT+FSMB8wxEv8R555DFkTNIsYSfh8JxQTMazI31Xtgv4awsf1iZmn15nxi2CUeA0BwsQaTtQmzCC1SsfqCYGUPoUHg1x3gzbi2zZz6KE6sP0gn7B72P7p+2/6tnNJI2besYcipPObyz0TL6njDnAGKADadtQxG1U8drxT6dO7qFoItgTjXtVMYD/cffv21ujCgbuQOT3d45z3yzjlCh3O6ufwTOF2+xgSDuNe0V8E6GG97LYVxyHdFX7 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 6/30/26 4:52 AM, Shakeel Butt wrote: > On Sun, Jun 28, 2026 at 09:28:51PM -0700, Suren Baghdasaryan wrote: >> On Sun, Jun 28, 2026 at 8:57 PM Harry Yoo wrote: >>> >>> > > [...] > > Thanks all for great discussion. Let me summarize the conclusion and please > correct me if I missed something. I think you didn't miss anything. > Let's keep the original one-line fix (serve the obj_exts array from a > strictly larger cache, making the relation a DAG). Right. > We will NOT gate it on> mem_alloc_profiling_enabled() as I floated earlier Right. > -- per Harry, is_kmalloc_normal(s) is already the right condition, Right. > and gating on> profiling would miss the SLUB_TINY + __GFP_RECLAIMABLE|__GFP_ACCOUNT memcg > case. Right. > So the bump stays unconditional for is_kmalloc_normal() caches. Right. > This over-allocates the array for larger caches, but only for profiling and > SLUB_TINY+MEMCG users (the latter unrealistic). Acceptable for a small, > backportable fix. Yes. Thanks! -- Cheers, Harry / Hyeonggon