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 2E982C4345F for ; Tue, 16 Apr 2024 07:04:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A79386B0087; Tue, 16 Apr 2024 03:04:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A28096B0088; Tue, 16 Apr 2024 03:04:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8A1B56B0089; Tue, 16 Apr 2024 03:04:01 -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 630946B0087 for ; Tue, 16 Apr 2024 03:04:01 -0400 (EDT) Received: from smtpin05.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id E444B1A0976 for ; Tue, 16 Apr 2024 07:04:00 +0000 (UTC) X-FDA: 82014505440.05.AF457F3 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf05.hostedemail.com (Postfix) with ESMTP id 901A6100005 for ; Tue, 16 Apr 2024 07:03:58 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=gQEBlKqW; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf05.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1713251038; 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=Do0uDpxoQP+HWYaPIE1vxxWsSiL7fxPwch7MqAGw4MQ=; b=FhaeTvp/shCV8mL6b1SglRb1TuoH8rtS0UaR+e1DahugVOgpps0jmEMmLUcQTHT1tm8k9/ yturXjoVXz6CU6F+i3dLyt0KvM79wLSW4woLtyFa8a8NjJq4LdIFcXcQo6S5/wrsHSeGP3 60oMEEaPn7bbyabmTv4r9UQOqBBgoxw= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=gQEBlKqW; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf05.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1713251038; a=rsa-sha256; cv=none; b=XB1YTfKh8C374wjIbxGjUpF1YUSsO4s/h/RPDijoRa9WYu7PU1G/xplwxEH0aE3iJHF4Jw ZI+4VkLSzaci2cYvlisKzaKDNukoa0ORufkTqzM9Uy1TGtW0yo7anRk+kgAhg3hwQW/S+z lPbjIrmR6GPjLqv73ZXAa2Re+mxu80c= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1713251037; 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=Do0uDpxoQP+HWYaPIE1vxxWsSiL7fxPwch7MqAGw4MQ=; b=gQEBlKqWOkk8O5P/rK0sIqMJoKGsQrd3D5yc15fsAkEtoPaMcW48oCty9bRXvtAMro+g4H RZ4nKZgbP3mGwO6riXJgaJxjMcz1nt1jnykP699IHhTbiKw0yEPtoilY8DzP3890xLAB7r FbL4iyrjhpiQRdOjQ2wdLe/hGuBEdb8= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-652-YnuFpp0UOgePwPopHdjaQQ-1; Tue, 16 Apr 2024 03:03:56 -0400 X-MC-Unique: YnuFpp0UOgePwPopHdjaQQ-1 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-41681022d82so15866555e9.1 for ; Tue, 16 Apr 2024 00:03:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1713251035; x=1713855835; 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=Do0uDpxoQP+HWYaPIE1vxxWsSiL7fxPwch7MqAGw4MQ=; b=GIvp9P1yST/+pDIJnT7fn7sQjiNEmgOlNLwUOYrH2p1OG3xJ6RtsVn8uU9Q0WCOFtt 7BtGsqLc48O9gwwYdvSDz/bzzBVFS+6JoVh0CKPvbyyOvbWX+xPZTGnQzuBYGD3bFjim T153ONMzI03GqnEFYU+AUpitvv796Wb48CfMKg0nuBB86moc43yoDT1wM9KywzUOeI7H 84rMaYDOZv2zFdwwptylPSQ607125EXWwImedJyP7zNHAX0BCIEc+VLCz6U+bq61hbPJ D90vbETj7AKt0s7aLtX/OBiGi/GfQU6hM3NyqYlbeev6uUKljcMFeqRd/J8EISAh5FqG 8S7w== X-Forwarded-Encrypted: i=1; AJvYcCX+Z1ditBs8yTVUcCc5WDCsHciDUS2FsCRP4BbSF/Grdf2pw4E0N81EeoYkr1WoKY22bWuo3QfijPfTfd99io3RmVw= X-Gm-Message-State: AOJu0YzBxPRCG0D6QFtcxpdAsrMuJwGEC7sERb54qnDjf13jVtq9Y9IG NzHORep5J8ItoyUjtYZd2qg+9RoCtt6NKPODW5XtehdexFo4k6mudKgkUb0/ZKrM+vbyCzz8Cxu 4esODjUwyiDX32vre/PvQdd4ny63F6aJbWeCnXy5h0sASSbh8 X-Received: by 2002:a05:600c:4511:b0:417:d624:1fe8 with SMTP id t17-20020a05600c451100b00417d6241fe8mr9161781wmo.30.1713251034916; Tue, 16 Apr 2024 00:03:54 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFDI8QdqqjCePdShbSV6lGjX1xBv3EcWc99MCeY9kMbwTLT6KvZn6PZ3xA81U/zj7FDvknu1g== X-Received: by 2002:a05:600c:4511:b0:417:d624:1fe8 with SMTP id t17-20020a05600c451100b00417d6241fe8mr9161755wmo.30.1713251034427; Tue, 16 Apr 2024 00:03:54 -0700 (PDT) Received: from [192.168.3.108] (p4ff2389d.dip0.t-ipconnect.de. [79.242.56.157]) by smtp.gmail.com with ESMTPSA id l6-20020a05600c4f0600b00418948a5eb0sm1159902wmq.32.2024.04.16.00.03.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 16 Apr 2024 00:03:54 -0700 (PDT) Message-ID: Date: Tue, 16 Apr 2024 09:03:52 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH rfc 0/3] mm: allow more high-order pages stored on PCP lists To: Barry Song <21cnbao@gmail.com>, Kefeng Wang Cc: Andrew Morton , Huang Ying , Mel Gorman , Ryan Roberts , Barry Song , Vlastimil Babka , Zi Yan , "Matthew Wilcox (Oracle)" , Jonathan Corbet , Yang Shi , Yu Zhao , linux-mm@kvack.org References: <20240415081220.3246839-1-wangkefeng.wang@huawei.com> <54623c8c-a94f-4f88-bf53-5f92c634f78a@huawei.com> <3b931621-7cd1-4df8-9070-535ecaee970e@redhat.com> <90501d59-e3f2-4ac4-9e42-4eca3bb0a91b@huawei.com> 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/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz 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+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 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-Stat-Signature: wtbzieqor37ee7yx1dxdefjejxg9n8fy X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 901A6100005 X-HE-Tag: 1713251038-373403 X-HE-Meta: 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 ZZrORw6t 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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 16.04.24 07:26, Barry Song wrote: > On Tue, Apr 16, 2024 at 4:58 PM Kefeng Wang wrote: >> >> >> >> On 2024/4/16 12:50, Kefeng Wang wrote: >>> >>> >>> On 2024/4/16 8:21, Barry Song wrote: >>>> On Tue, Apr 16, 2024 at 12:18 AM Kefeng Wang >>>> wrote: >>>>> >>>>> >>>>> >>>>> On 2024/4/15 18:52, David Hildenbrand wrote: >>>>>> On 15.04.24 10:59, Kefeng Wang wrote: >>>>>>> >>>>>>> >>>>>>> On 2024/4/15 16:18, Barry Song wrote: >>>>>>>> On Mon, Apr 15, 2024 at 8:12 PM Kefeng Wang >>>>>>>> wrote: >>>>>>>>> >>>>>>>>> Both the file pages and anonymous pages support large folio, >>>>>>>>> high-order >>>>>>>>> pages except PMD_ORDER will also be allocated frequently which could >>>>>>>>> increase the zone lock contention, allow high-order pages on pcp >>>>>>>>> lists >>>>>>>>> could reduce the big zone lock contention, but as commit >>>>>>>>> 44042b449872 >>>>>>>>> ("mm/page_alloc: allow high-order pages to be stored on the per-cpu >>>>>>>>> lists") >>>>>>>>> pointed, it may not win in all the scenes, add a new control >>>>>>>>> sysfs to >>>>>>>>> enable or disable specified high-order pages stored on PCP lists, >>>>>>>>> the order >>>>>>>>> (PAGE_ALLOC_COSTLY_ORDER, PMD_ORDER) won't be stored on PCP list by >>>>>>>>> default. >>>>>>>> >>>>>>>> This is precisely something Baolin and I have discussed and intended >>>>>>>> to implement[1], >>>>>>>> but unfortunately, we haven't had the time to do so. >>>>>>> >>>>>>> Indeed, same thing. Recently, we are working on unixbench/lmbench >>>>>>> optimization, I tested Multi-size THP for anonymous memory by >>>>>>> hard-cord >>>>>>> PAGE_ALLOC_COSTLY_ORDER from 3 to 4[1], it shows some improvement but >>>>>>> not for all cases and not very stable, so re-implemented it by >>>>>>> according >>>>>>> to the user requirement and enable it dynamically. >>>>>> >>>>>> I'm wondering, though, if this is really a suitable candidate for a >>>>>> sysctl toggle. Can anybody really come up with an educated guess for >>>>>> these values? >>>>> >>>>> Not sure this is suitable in sysctl, but mTHP anon is enabled in sysctl, >>>>> we could trace __alloc_pages() and do order statistic to decide to >>>>> choose the high-order to be enabled on PCP. >>>>> >>>>>> >>>>>> Especially reading "Benchmarks Score shows a little improvoment(0.28%)" >>>>>> and "it may not win in all the scenes", to me it mostly sounds like >>>>>> "minimal impact" -- so who cares? >>>>> >>>>> Even though lock conflicts are eliminated, there is very limited >>>>> performance improvement(even maybe fluctuation), it is not a good >>>>> testcase to show improvement, just show the zone-lock issue, we need to >>>>> find other better testcase, maybe some test on Andriod(heavy use 64K, no >>>>> PMD THP), or LKP maybe give some help? >>>>> >>>>> I will try to find other testcase to show the benefit. >>>> >>>> Hi Kefeng, >>>> >>>> I wonder if you will see some major improvements on mTHP 64KiB using >>>> the below microbench I wrote just now, for example perf and time to >>>> finish the program >>>> >>>> #define DATA_SIZE (2UL * 1024 * 1024) >>>> >>>> int main(int argc, char **argv) >>>> { >>>> /* make 32 concurrent alloc and free of mTHP */ >>>> fork(); fork(); fork(); fork(); fork(); >>>> >>>> for (int i = 0; i < 100000; i++) { >>>> void *addr = mmap(NULL, DATA_SIZE, PROT_READ | >>>> PROT_WRITE, >>>> MAP_ANONYMOUS | MAP_PRIVATE, -1, 0); >>>> if (addr == MAP_FAILED) { >>>> perror("fail to malloc"); >>>> return -1; >>>> } >>>> memset(addr, 0x11, DATA_SIZE); >>>> munmap(addr, DATA_SIZE); >>>> } >>>> >>>> return 0; >>>> } >>>> >> >> Rebased on next-20240415, >> >> echo never > /sys/kernel/mm/transparent_hugepage/enabled >> echo always > /sys/kernel/mm/transparent_hugepage/hugepages-64kB/enabled >> >> Compare with >> echo 0 > /sys/kernel/mm/transparent_hugepage/hugepages-64kB/pcp_enabled >> echo 1 > /sys/kernel/mm/transparent_hugepage/hugepages-64kB/pcp_enabled >> >>> >>> 1) PCP disabled >>> 1 2 3 4 5 average >>> real 200.41 202.18 203.16 201.54 200.91 201.64 >>> user 6.49 6.21 6.25 6.31 6.35 6.322 >>> sys 193.3 195.39 196.3 194.65 194.01 194.73 >>> >>> 2) PCP enabled >>> real 198.25 199.26 195.51 199.28 189.12 196.284 >>> -2.66% >>> user 6.21 6.02 6.02 6.28 6.21 6.148 -2.75% >>> sys 191.46 192.64 188.96 192.47 182.39 189.584 >>> -2.64% >>> >>> for above test, time reduce 2.x% > > This is an improvement from 0.28%, but it's still below my expectations. Yes, it's noise. Maybe we need a system with more Cores/Sockets? But it does feel a bit like we're trying to come up with the problem after we have a solution; I'd have thought some existing benchmark could highlight if that is worth it. -- Cheers, David / dhildenb