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 X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4D6BFC43381 for ; Thu, 28 Mar 2019 06:05:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C4FDD20700 for ; Thu, 28 Mar 2019 06:05:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=messagingengine.com header.i=@messagingengine.com header.b="z/PJ0bvM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C4FDD20700 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=iki.fi Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6031C6B0003; Thu, 28 Mar 2019 02:05:41 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5898E6B0006; Thu, 28 Mar 2019 02:05:41 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 451236B0007; Thu, 28 Mar 2019 02:05:41 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) by kanga.kvack.org (Postfix) with ESMTP id 1B7346B0003 for ; Thu, 28 Mar 2019 02:05:41 -0400 (EDT) Received: by mail-qk1-f200.google.com with SMTP id l187so16685996qkd.7 for ; Wed, 27 Mar 2019 23:05:41 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:dkim-signature:subject:to:cc:references:from :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=jqtazJHsx+b9ct1DOtMFjfvs6F8nSs4P+e+seowAwTM=; b=s/Qb8Mz8nJEC6ucuBr9cjTmxxsffx1f2WjmnkjnDiSTV7fUT48kKwpf4+nd54vCtjB 2Y20bYF0ynDP2QJhsCiO+GgtUVGPS/tDhawcjeqDfmLwfuN7wlTW7ZYO768WIZKgZcwt 4JZ7W4xuSMtznT3V7Mco4EGyhVHytLeEyuCjEs6p77903XOfCx+OYmCv4YqmGkqC9lsM Wvov/2v3ioiVEPTvNVRlG7aSkY2Evq/vZlUs3fusJqwUvO9D+uKkHzBHT+EUiUmaM5ZK 0wLXnDA5uE4HZGyZL1ghv0QK1PUn2oYsDxpzAjN8K9Z2+UBVKDgSNMOgaJOBAxPTVj0+ M0pQ== X-Gm-Message-State: APjAAAXJ3QGyj5WsTk3xjxo0S3jR3u1c6904gf6Fgv5Iohs0Ku6Kxjl2 E0TDyfgAzn0vW5OGAHR62q6wudUq/iErd1Jidiv8E3iDJJQYvEzPO89dacwERgZJMtOvEF10+ou tlrgGBic2urtp9IL8gL1bAP4LrQpx2ToKREw/K76WuQXxIh60L2ne4zaOQLYb9+A= X-Received: by 2002:ae9:f202:: with SMTP id m2mr31849237qkg.52.1553753140755; Wed, 27 Mar 2019 23:05:40 -0700 (PDT) X-Google-Smtp-Source: APXvYqx404b2mRE+mV7ndZAAF+3WXB4Doru1URW71InRQ/ucoS3JSrPhXJs2rB25n3amIhzx8hgl X-Received: by 2002:ae9:f202:: with SMTP id m2mr31849214qkg.52.1553753140164; Wed, 27 Mar 2019 23:05:40 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1553753140; cv=none; d=google.com; s=arc-20160816; b=u6UtdhkadpEH23aVDpOhLOWQNzCqlKwx0Ko9WI3L+U4md4KZeppVa7sfBj7899i1zI gODTtEFduw150e3gt6EPHX8Mm/Sn01owx4FyMBPWYZrVx1DePqWKFID80UtfRX6v1zi3 2794qKKVo7nq5Po9y1/F1/mMt+niBAINJS4SNomURY049L9w6woSJ5GtgmKzYMLMucZJ HtAz4+CRmjYe4ORUY14rmRAXRwgcrRqE+wElQkhqfN+nYreLvus0R28FtEusYSotEWic xwCPcxfF3C3J2iKcsZCaFeFU1mJLVRrZEMYO/meQLQIRRhu6wBqdwWo4Lzw9EqRcp/vl P5og== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=content-transfer-encoding:content-language:in-reply-to:mime-version :user-agent:date:message-id:from:references:cc:to:subject :dkim-signature; bh=jqtazJHsx+b9ct1DOtMFjfvs6F8nSs4P+e+seowAwTM=; b=cbtMl9EhhD/cDqEaNJtursYjRQ6X3zPZR0owLkzDVLy9/2eP3kifKfZ/dnm4VZgANd UW9f+oRC35tQdYQFeXWwVoh+X/4kw9llWh8hWydpkD5YEGBtpGA9xBTcmNFLv/JXLHCm T50zuALbMR4GYzYt0n36dJcDqP11L6SNKmF1vkiDJDbX0M1qGT44goDGNQMe+oL5/lc/ 5jOph6a759qbd7DtIowfVrSzdIE+FIjiNfJp9veK1DFhIsmtcnb5sezcGjDlpi+dvTks EZH990fQqsx/UaN1vEEJA5PGi4wtFnH6T1YQQCWRBO0RlH8BLEFmPF93xCTlPLjvkCEh JN/A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@messagingengine.com header.s=fm2 header.b="z/PJ0bvM"; spf=neutral (google.com: 66.111.4.25 is neither permitted nor denied by domain of penberg@iki.fi) smtp.mailfrom=penberg@iki.fi; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=iki.fi Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com. [66.111.4.25]) by mx.google.com with ESMTPS id l88si798804qtd.251.2019.03.27.23.05.39 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 27 Mar 2019 23:05:40 -0700 (PDT) Received-SPF: neutral (google.com: 66.111.4.25 is neither permitted nor denied by domain of penberg@iki.fi) client-ip=66.111.4.25; Authentication-Results: mx.google.com; dkim=pass header.i=@messagingengine.com header.s=fm2 header.b="z/PJ0bvM"; spf=neutral (google.com: 66.111.4.25 is neither permitted nor denied by domain of penberg@iki.fi) smtp.mailfrom=penberg@iki.fi; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=iki.fi Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.nyi.internal (Postfix) with ESMTP id B8EF92106A; Thu, 28 Mar 2019 02:05:39 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute4.internal (MEProxy); Thu, 28 Mar 2019 02:05:39 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-me-proxy:x-me-proxy:x-me-sender:x-me-sender :x-sasl-enc; s=fm2; bh=jqtazJHsx+b9ct1DOtMFjfvs6F8nSs4P+e+seowAw TM=; b=z/PJ0bvMjNqjIRFMSifCfyHzH4pwkBOj+fX7DVLxdUaCOxD3o3cpxDRTU TRIBku+dtNMhmuuDTsJZyE98dZWQtKmh6upJVYkQuC/PYNZ88jAOpdwJox5DBg4T awNU+jHqh92Enu/+aAZu0g4M48fuCumuGVGkbqlhw67MkLWYBLQli03Aq3RiTc+E 9BnomWRH0LnvQSeF6xTr/dEUpA1H3zqvL0knmozMCbfYjFxifMUethwluvXr+9/E ptaAaEoCnHnbpZvRjF08qSRxYZX1G2mQArmnInOut1SXQWT+18itpmE5GSyVL3iY X5zzyDmyu3NxX41Sq6JLSSHiXMGlQ== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedutddrkeefgddutdduucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefuvfhfhffkffgfgggjtgfgsehtje ertddtfeejnecuhfhrohhmpefrvghkkhgrucfgnhgsvghrghcuoehpvghnsggvrhhgsehi khhirdhfiheqnecukfhppeekledrvdejrdeffedrudejfeenucfrrghrrghmpehmrghilh hfrhhomhepphgvnhgsvghrghesihhkihdrfhhinecuvehluhhsthgvrhfuihiivgeptd X-ME-Proxy: Received: from Pekka-MacBook.local (89-27-33-173.bb.dnainternet.fi [89.27.33.173]) by mail.messagingengine.com (Postfix) with ESMTPA id 039F9E442F; Thu, 28 Mar 2019 02:05:34 -0400 (EDT) Subject: Re: [PATCH v4] kmemleak: survive in a low-memory situation To: Qian Cai , akpm@linux-foundation.org Cc: catalin.marinas@arm.com, cl@linux.com, mhocko@kernel.org, willy@infradead.org, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20190327005948.24263-1-cai@lca.pw> From: Pekka Enberg Message-ID: Date: Thu, 28 Mar 2019 08:05:31 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:60.0) Gecko/20100101 Thunderbird/60.6.0 MIME-Version: 1.0 In-Reply-To: <20190327005948.24263-1-cai@lca.pw> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit 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: Hi, On 27/03/2019 2.59, Qian Cai wrote: > Unless there is a brave soul to reimplement the kmemleak to embed it's > metadata into the tracked memory itself in a foreseeable future, this > provides a good balance between enabling kmemleak in a low-memory > situation and not introducing too much hackiness into the existing > code for now. Unfortunately I am not that brave soul, but I'm wondering what the complication here is? It shouldn't be too hard to teach calculate_sizes() in SLUB about a new SLAB_KMEMLEAK flag that reserves spaces for the metadata. - Pekka