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 536BCC87FD2 for ; Thu, 7 Aug 2025 18:02:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B20176B00B7; Thu, 7 Aug 2025 14:02:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AF7CA6B00BB; Thu, 7 Aug 2025 14:02:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9E6366B00BC; Thu, 7 Aug 2025 14:02:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 8DAAC6B00B7 for ; Thu, 7 Aug 2025 14:02:01 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 3C9A5137744 for ; Thu, 7 Aug 2025 18:02:01 +0000 (UTC) X-FDA: 83750730042.30.D45584C Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf09.hostedemail.com (Postfix) with ESMTP id B554C140002 for ; Thu, 7 Aug 2025 18:01:58 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=VF2yECpk; spf=pass (imf09.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1754589718; 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=mhUS2sM+ExcCQ6yCHHvb67H8y6ZDFz4/8Rje0oa/xWU=; b=IOKvnaUZx7RAnKIoSCLfrcrwEIwsmBhnSW2fS/nDYdM68io97Qc7DMOCfo5AEDrRKWK+a4 jVbZv9PaJ3kk3iZlsEjt1TOwNLnRi6SyMh5fAKZGHJ3dASUYTnCZgMzTpn5urCvpEcefLb OijK1hW07CAld2MJNvAIG4Kd8jtwBEU= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=VF2yECpk; spf=pass (imf09.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1754589718; a=rsa-sha256; cv=none; b=6K2zJ9xhw49rNVlj/WJqb3qtjulxOA2ay3EML7vBYcu4sslcA1g42c9QixMy8OSdpKdGYp IGJwJepuIh1HTncEgpZ6J2/zpbaDIr0NTm9/FNE9IFCO0EHyxKkI8rTS3RV5/7mSS2+1A7 EOu414Myta35wqtpKxEhI0mRr0HmfgM= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1754589718; h=from:from: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:autocrypt:autocrypt; bh=mhUS2sM+ExcCQ6yCHHvb67H8y6ZDFz4/8Rje0oa/xWU=; b=VF2yECpkuGVWLsUU2Bc67zfqIfJKakWnJqXdpQZMCSRD7+sc9dstxzladTRxDjoLTE5Jmz 1S4XJjcbZqMEw7DHNBSL4SOmD9aZBENKC9NrjzBxmLSp2xNRvte7IKbQ0CYD8y50DORaKq AC3LCR1GfryxLssm+ghKTGDdtF6DFPI= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-28-vGkuJ2u7NTSTvt_9pw7-QQ-1; Thu, 07 Aug 2025 14:01:55 -0400 X-MC-Unique: vGkuJ2u7NTSTvt_9pw7-QQ-1 X-Mimecast-MFC-AGG-ID: vGkuJ2u7NTSTvt_9pw7-QQ_1754589715 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-459e30eeea3so7727735e9.0 for ; Thu, 07 Aug 2025 11:01:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1754589714; x=1755194514; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=mhUS2sM+ExcCQ6yCHHvb67H8y6ZDFz4/8Rje0oa/xWU=; b=dNTrCTdACdxcpglxxXud9Z+NosZHW/FlQE5OFOF7wogqDzVsLJmxMFNsSVcS40ZtgC q140uLCGB4ski8rOpFCTW2tvG66hfzz7Z6Vi0bfGn7szXJVBqs9zH/MIGZPs2kTzPVQo duLAqctDwqQhJvb3+PnjJ5j0dmqh2o1SEQzpg1+5+KN/E2OfoVfAgBLcrO+w3F6LalJQ /hrhD4QvY8jNxK1PDiSQaqFYUCcn/P0fzoFW7ZstPUlAlDCEJ6TVUBqa+BhV7w13lqa8 VENd6jDev7x/MvibUfLamGJOK43ezAZGgQPpUKfPqyKH2JwUgOzHWtvwB2rEuIpYY1eo 7Eqw== X-Forwarded-Encrypted: i=1; AJvYcCXMzFIcCg+Vb49wcm1/IiOnLckXzhKBMZriyaCHH+NFHeLP+FVKPIuiPR8yAj14CvIchgMIjuSj1g==@kvack.org X-Gm-Message-State: AOJu0Yy0sVs3Ybd3m1DL7oM+AwcF7rmpRkt4IdscCutw1XVR1bz9zQ9p a6aDFXrZSQepfenBHdhqufI50X7/+4B9Jr2ZxsMxF7VgF+N3pWus1v7c0RnR3H+D8MdfvosIN3V iHSbUu/IumEFZVEQTL58g0WQlHRxuyZN3zcqmmpNxLedqoTHHnVD4 X-Gm-Gg: ASbGncuG3y6p44EGm4DPySGBgtDsSueCs8PpfPFjBOlzN3zZBCZlypCj2/KyUXfQHvw eT82UKjskl+K+T8BYUJm6BZR1SioGAnMbrJfgYWteO0w9UesIjpoM/Fw1M/4k/zHVV6Aw/hYw3A V6DIHwtAzrjHq7s0vBTdaONSd/vlcy8x13ZMhGQZQ9oN6MXg+djqhhIHW0dI/L1IHuYILE5DVFf qcsveCQ0EDjnkXyFmsJSX804g5CAx3fmmcFreYWacx/iG72b1BD/nUqgMgps70PpiIfXEK4nK62 RhK+0h70lRKAKg95IZhSdacRWtBVpc9zdGcs3r5Z3oD4UUDWJFtFOAHloLRBbhOyPAbvY89RIxN X+cAlRxlswjSNzFB/ekQjW9w6xPi9POqyu56CfvkL+F6ZCLDBmoE1WD9lpUvH1/kegT8= X-Received: by 2002:a05:600c:46c8:b0:459:ddad:a3a3 with SMTP id 5b1f17b1804b1-459e74a4ad6mr64013475e9.25.1754589714414; Thu, 07 Aug 2025 11:01:54 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGxcVatWP7rFIfVWx9CqdmH8FLM3Nm306vOiRTmVXgWVKdqiIY4890kJtBR5KGb3c604MXHrw== X-Received: by 2002:a05:600c:46c8:b0:459:ddad:a3a3 with SMTP id 5b1f17b1804b1-459e74a4ad6mr64012855e9.25.1754589713826; Thu, 07 Aug 2025 11:01:53 -0700 (PDT) Received: from ?IPV6:2003:d8:2f49:bc00:12fa:1681:c754:1630? (p200300d82f49bc0012fa1681c7541630.dip0.t-ipconnect.de. [2003:d8:2f49:bc00:12fa:1681:c754:1630]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3b79c3c33fesm27989570f8f.29.2025.08.07.11.01.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 07 Aug 2025 11:01:53 -0700 (PDT) Message-ID: Date: Thu, 7 Aug 2025 20:01:51 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [linus:master] [mm] f822a9a81a: stress-ng.bigheap.realloc_calls_per_sec 37.3% regression To: Lorenzo Stoakes , Jann Horn Cc: kernel test robot , Dev Jain , oe-lkp@lists.linux.dev, lkp@intel.com, linux-kernel@vger.kernel.org, Andrew Morton , Barry Song , Pedro Falcato , Anshuman Khandual , Bang Li , Baolin Wang , bibo mao , Hugh Dickins , Ingo Molnar , Lance Yang , Liam Howlett , Matthew Wilcox , Peter Xu , Qi Zheng , Ryan Roberts , Vlastimil Babka , Yang Shi , Zi Yan , linux-mm@kvack.org References: <202508071609.4e743d7c-lkp@intel.com> <9e3a59b2-11c0-43ca-aff3-414091f04aa4@lucifer.local> From: David Hildenbrand Autocrypt: addr=david@redhat.com; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAmgsLPQFCRvGjuMACgkQTd4Q 9wD/g1o0bxAAqYC7gTyGj5rZwvy1VesF6YoQncH0yI79lvXUYOX+Nngko4v4dTlOQvrd/vhb 02e9FtpA1CxgwdgIPFKIuXvdSyXAp0xXuIuRPQYbgNriQFkaBlHe9mSf8O09J3SCVa/5ezKM OLW/OONSV/Fr2VI1wxAYj3/Rb+U6rpzqIQ3Uh/5Rjmla6pTl7Z9/o1zKlVOX1SxVGSrlXhqt kwdbjdj/csSzoAbUF/duDuhyEl11/xStm/lBMzVuf3ZhV5SSgLAflLBo4l6mR5RolpPv5wad GpYS/hm7HsmEA0PBAPNb5DvZQ7vNaX23FlgylSXyv72UVsObHsu6pT4sfoxvJ5nJxvzGi69U s1uryvlAfS6E+D5ULrV35taTwSpcBAh0/RqRbV0mTc57vvAoXofBDcs3Z30IReFS34QSpjvl Hxbe7itHGuuhEVM1qmq2U72ezOQ7MzADbwCtn+yGeISQqeFn9QMAZVAkXsc9Wp0SW/WQKb76 FkSRalBZcc2vXM0VqhFVzTb6iNqYXqVKyuPKwhBunhTt6XnIfhpRgqveCPNIasSX05VQR6/a OBHZX3seTikp7A1z9iZIsdtJxB88dGkpeMj6qJ5RLzUsPUVPodEcz1B5aTEbYK6428H8MeLq NFPwmknOlDzQNC6RND8Ez7YEhzqvw7263MojcmmPcLelYbfOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCaCwtJQUJG8aPFAAKCRBN3hD3AP+DWlDnD/4k2TW+HyOOOePVm23F5HOhNNd7nNv3 Vq2cLcW1DteHUdxMO0X+zqrKDHI5hgnE/E2QH9jyV8mB8l/ndElobciaJcbl1cM43vVzPIWn 01vW62oxUNtEvzLLxGLPTrnMxWdZgxr7ACCWKUnMGE2E8eca0cT2pnIJoQRz242xqe/nYxBB /BAK+dsxHIfcQzl88G83oaO7vb7s/cWMYRKOg+WIgp0MJ8DO2IU5JmUtyJB+V3YzzM4cMic3 bNn8nHjTWw/9+QQ5vg3TXHZ5XMu9mtfw2La3bHJ6AybL0DvEkdGxk6YHqJVEukciLMWDWqQQ RtbBhqcprgUxipNvdn9KwNpGciM+hNtM9kf9gt0fjv79l/FiSw6KbCPX9b636GzgNy0Ev2UV m00EtcpRXXMlEpbP4V947ufWVK2Mz7RFUfU4+ETDd1scMQDHzrXItryHLZWhopPI4Z+ps0rB CQHfSpl+wG4XbJJu1D8/Ww3FsO42TMFrNr2/cmqwuUZ0a0uxrpkNYrsGjkEu7a+9MheyTzcm vyU2knz5/stkTN2LKz5REqOe24oRnypjpAfaoxRYXs+F8wml519InWlwCra49IUSxD1hXPxO WBe5lqcozu9LpNDH/brVSzHCSb7vjNGvvSVESDuoiHK8gNlf0v+epy5WYd7CGAgODPvDShGN g3eXuA== Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: WCLtpr9Zy-7kI1g4QVTM29jCdcqCzNvLfY140xkMUNE_1754589715 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Queue-Id: B554C140002 X-Rspamd-Server: rspam06 X-Stat-Signature: ftjapexboxq4y4yrba8tczwf96mpossf X-HE-Tag: 1754589718-583056 X-HE-Meta: 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 z78jF9v9 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 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 07.08.25 19:51, Lorenzo Stoakes wrote: > On Thu, Aug 07, 2025 at 07:46:39PM +0200, Jann Horn wrote: >> On Thu, Aug 7, 2025 at 7:41 PM Lorenzo Stoakes >> wrote: >>> On Thu, Aug 07, 2025 at 07:37:38PM +0200, Jann Horn wrote: >>>> On Thu, Aug 7, 2025 at 10:28 AM Lorenzo Stoakes >>>> wrote: >>>>> On Thu, Aug 07, 2025 at 04:17:09PM +0800, kernel test robot wrote: >>>>>> 94dab12d86cf77ff f822a9a81a31311d67f260aea96 >>>>>> ---------------- --------------------------- >>>>>> %stddev %change %stddev >>>>>> \ | \ >>>>>> 13777 ą 37% +45.0% 19979 ą 27% numa-vmstat.node1.nr_slab_reclaimable >>>>>> 367205 +2.3% 375703 vmstat.system.in >>>>>> 55106 ą 37% +45.1% 79971 ą 27% numa-meminfo.node1.KReclaimable >>>>>> 55106 ą 37% +45.1% 79971 ą 27% numa-meminfo.node1.SReclaimable >>>>>> 559381 -37.3% 350757 stress-ng.bigheap.realloc_calls_per_sec >>>>>> 11468 +1.2% 11603 stress-ng.time.system_time >>>>>> 296.25 +4.5% 309.70 stress-ng.time.user_time >>>>>> 0.81 ą187% -100.0% 0.00 perf-sched.sch_delay.avg.ms.__cond_resched.zap_pte_range.zap_pmd_range.isra.0 >>>>>> 9.36 ą165% -100.0% 0.00 perf-sched.sch_delay.max.ms.__cond_resched.zap_pte_range.zap_pmd_range.isra.0 >>>>>> 0.81 ą187% -100.0% 0.00 perf-sched.wait_time.avg.ms.__cond_resched.zap_pte_range.zap_pmd_range.isra.0 >>>>>> 9.36 ą165% -100.0% 0.00 perf-sched.wait_time.max.ms.__cond_resched.zap_pte_range.zap_pmd_range.isra.0 >>>>>> 5.50 ą 17% +390.9% 27.00 ą 56% perf-c2c.DRAM.local >>>>>> 388.50 ą 10% +114.7% 834.17 ą 33% perf-c2c.DRAM.remote >>>>>> 1214 ą 13% +107.3% 2517 ą 31% perf-c2c.HITM.local >>>>>> 135.00 ą 19% +130.9% 311.67 ą 32% perf-c2c.HITM.remote >>>>>> 1349 ą 13% +109.6% 2829 ą 31% perf-c2c.HITM.total >>>>> >>>>> Yeah this also looks pretty consistent too... >>>> >>>> FWIW, HITM hat different meanings depending on exactly which >>>> microarchitecture that test happened on; the message says it is from >>>> Sapphire Rapids, which is a successor of Ice Lake, so HITM is less >>>> meaningful than if it came from a pre-IceLake system (see >>>> https://lore.kernel.org/all/CAG48ez3RmV6SsVw9oyTXxQXHp3rqtKDk2qwJWo9TGvXCq7Xr-w@mail.gmail.com/). >>>> >>>> To me those numbers mainly look like you're accessing a lot more >>>> cache-cold data. (On pre-IceLake they would indicate cacheline >>>> bouncing, but I guess here they probably don't.) And that makes sense, >>>> since before the patch, this path was just moving PTEs around without >>>> looking at the associated pages/folios; basically more or less like a >>>> memcpy() on x86-64. But after the patch, for every 8 bytes that you >>>> copy, you have to load a cacheline from the vmemmap to get the page. >>> >>> Yup this is representative of what my investigation is showing. >>> >>> I've narrowed it down but want to wait to report until I'm sure... >>> >>> But yeah we're doing a _lot_ more work. >>> >>> I'm leaning towards disabling except for arm64 atm tbh, seems mremap is >>> especially sensitive to this (I found issues with this with my abortive mremap >>> anon merging stuff too, but really expected it there...) >> >> Another approach would be to always read and write PTEs in >> contpte-sized chunks here, without caring whether they're actually >> contiguous or whatever, or something along those lines. > > Not sure I love that, you'd have to figure out offset without cont pte batch and > can it vary? And we're doing this on non-arm64 arches for what reason? > > And would it solve anything really? We'd still be looking at folio, yes less > than now, but uselessly for arches that don't benefit? > > The basis of this series was (and I did explicitly ask) that it wouldn't harm > other arches. We'd need some hint to detect "this is either small" or "this is unbatchable". Sure, we could use pte_batch_hint(), but I'm curious if x86 would also benefit with larger folios (e.g., 64K, 128K) with this patch. -- Cheers, David / dhildenb