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]) by smtp.lore.kernel.org (Postfix) with ESMTP id F0349C52D71 for ; Fri, 9 Aug 2024 09:05:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8C1C26B0088; Fri, 9 Aug 2024 05:05:57 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 84A9F6B0092; Fri, 9 Aug 2024 05:05:57 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6ECB96B0095; Fri, 9 Aug 2024 05:05:57 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 500F36B0088 for ; Fri, 9 Aug 2024 05:05:57 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id EBC9140AE7 for ; 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s=arc-20220608; d=hostedemail.com; t=1723194281; a=rsa-sha256; cv=none; b=4Sg54uowqR0GUmoTbr/61A7Cw0dTChyhY9mtPmGGkKCpgLMwoByBQO5CcU4Jn2cs/lIxQa 0tDZTQ5ZTQZZEyg8FgBae01VvvJr1rRSdHDuNwD5p+NGDXlRe2BxzBBSOrqzgBIbQ4Wn29 0f/tU61NHFyqN8v4JhzY6r63IzwyP1M= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf01.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 24DD2FEC; Fri, 9 Aug 2024 02:06:20 -0700 (PDT) Received: from [10.57.95.64] (unknown [10.57.95.64]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A18EF3F6A8; Fri, 9 Aug 2024 02:05:52 -0700 (PDT) Message-ID: <9f8ba5c8-5bc3-4af2-96d2-2f52ee923ef5@arm.com> Date: Fri, 9 Aug 2024 10:05:51 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC 1/2] mm: collect the number of anon large folios Content-Language: en-GB To: David Hildenbrand , Barry Song <21cnbao@gmail.com>, akpm@linux-foundation.org, linux-mm@kvack.org Cc: chrisl@kernel.org, kaleshsingh@google.com, kasong@tencent.com, linux-kernel@vger.kernel.org, ioworker0@gmail.com, baolin.wang@linux.alibaba.com, ziy@nvidia.com, hanchuanhua@oppo.com, Barry Song References: <20240808010457.228753-1-21cnbao@gmail.com> <20240808010457.228753-2-21cnbao@gmail.com> <1222cd76-e732-4238-9413-61843249c1e8@arm.com> <4465afdc-23e9-4844-a0a0-519f49b1229c@redhat.com> <616401ea-289d-4ae2-acde-6704b0fa9c46@redhat.com> From: Ryan Roberts In-Reply-To: <616401ea-289d-4ae2-acde-6704b0fa9c46@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 30B3740009 X-Stat-Signature: xw9j95k7do4rtnge54khbj66yxidceap X-Rspam-User: X-HE-Tag: 1723194354-441392 X-HE-Meta: U2FsdGVkX19kEPCUr8O6sP2wAJM8bTRE8P9sON29mIraBbXkPKe2KmWMCQfUd1a92HU4To1Ulol+oxx1ID0kB+0vcdnhgaWXpbOvI2POSUaO/v0V0MWS3DWpcjgE3h3PvmydProKcyeBQiFNIAD9n0RuT7V0c9KF8dOM2h63YRIM2F912w0z2GLZpvEkzeBfg8CGhUNs8MC+7y11RwYaFCz2xJ/OpNzupsHJHtWYJskTSNL+c/rasyArGCAVCZUrlo6WeBxgWUEXNBDtsy2MKTB0kTfAmn3AunOpY2BIrW8Fk5qrsW7HTKpnneBPvP2Oh5iwozrxq+b6WpmmvvVW/s3htyXo4unB68X5c0UcApg7tPH+daYHovSidJPpbTQpOv4qiBA+Y26/8nr+Soo+n1OsEhf1zjURoAK0YNRG+S8+tSbZ/uC3TLmADIVxqyYYLoyI4Noil8Fpcoaxh3BQVH5EuqtyiModrYXt23J3D0Qw3kQGchTrHGTG/r8m5N8eSv9eDt3bA4FnSrohZMuxrdrRp9Pwf5TywqLsFzEwNyMQGoax5HpG1jJvbhXVG4H6BECzsEuG7bli0Jbt9sBQwXj9j/rhgnrQ9/4pT9I70O1KjujwPwBzrhppJtXaJq4rZTmAfcLAOTuW1Wz+stfs5l9WyUrESq/4G/OOA01iKfa/TbDZqIxGVmJV+hUWThIaOktl2UqJm/p+/v2eSj+ww9DLPPaOzHXE0YVX3oZcZHvZuVYgYXpSOOpmH3sBiLrAJ0N4Rs2YIKLd8j8bCoxK803ZQGiZRLKX+wYhyENlwxgpIdeBc1YfZo7ICyCD9SFMtBjLL+2Fro/Jdrz6U/l1XGyo317XAg1D027LyN6CJaXDC9Tc5Hbdm9kAfSfLSFfvi5l5rxjlVkyfff5SUaaAY+SwRKy90D/ZZ/qvTDtrNxhJjagZAb+CAXAccBy6LT9GiAiScxvfg46qpg4Tua8 u+Y+eAlt V7Q6wu/tACSRdK/wHmJv4IBEvAqVcqGkZTGACk7TCEna5hJihye+3dXK8lBYupxzujqDUWk3s+bJPNPxbCX1mWMcgU2NNre06S2CCXVKrO2dUL9s427d8bDghR+EW4fctxGwNbU5pCkT4Ics9YnHcQisGCQ== 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: List-Subscribe: List-Unsubscribe: On 09/08/2024 09:58, David Hildenbrand wrote: > On 09.08.24 10:42, David Hildenbrand wrote: >>>> Not sure I fully understand why David prefers to do the unaccounting at >>>> free-time though? It feels unbalanced to me to increment when first mapped but >>>> decrement when freed. Surely its safer to either use alloc/free or use first >>>> map/last map? >>>> >>>> If using alloc/free isn't there a THP constructor/destructor that prepares the >>>> deferred list? (My memory may be failing me). Could we use that? >>> >>> Additionally, if we wanted to extend (eventually) to track the number of shmem >>> and file mthps in additional counters, could we also account using similar folio >>> free-time hooks? If not, it might be an argument to account in rmap_unmap to be >>> consistent for all? >> >> Again, see NR_FILE_THPS handling. No rmap over-complication please. > > ... not to mention that it is non-sensical to only count pageache folios that > are mapped to user space ;) Yes, good point. I'll get back in my box. :)