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 9B99BC35274 for ; Mon, 18 Dec 2023 11:29:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2B4B88D0008; Mon, 18 Dec 2023 06:29:49 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 265EB8D0001; Mon, 18 Dec 2023 06:29:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 106648D0008; Mon, 18 Dec 2023 06:29:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id EEC288D0001 for ; Mon, 18 Dec 2023 06:29:48 -0500 (EST) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id C138E1C0E57 for ; Mon, 18 Dec 2023 11:29:48 +0000 (UTC) X-FDA: 81579719256.23.1DE233E Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf02.hostedemail.com (Postfix) with ESMTP id 6686E8000A for ; Mon, 18 Dec 2023 11:29:46 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=YPrwcFgy; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf02.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 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=1702898986; 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=GSd7La5h0M9e2qVPUNvunxZbxK4L5T2M7NX5H+PBXVk=; b=pp0CcSsK4g3V31It6KTY5EyAx8UjenmLC7RVNpDOLA0mEIzuPN+Neqm0qTbK31dm5bqVT8 TpZwD50ibJwKTd8CUVS0ojAs3A9f/Nj9sZ32X7/e0ZLakCgN+PXHGxBIjBpbXdQ4RP2D+z neN3EMzmy3xYvnII8Fp/qNEWYU6RHm8= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=YPrwcFgy; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf02.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1702898986; a=rsa-sha256; cv=none; b=dVcPDOWlyhCmDldJjbsYMwKYIUZS7C5Uu5nlTwyVfFesV3V9ng4xrR2B2laaS/RDmZP3zB JXL7GqRWPcbhkwb8kKN9yPcjq10giuMJzjrYGkgPao1ZkownaUl1XvD3hhc8h9dvhii37o mHSUU0YVgALze7/yncjKNx5sGA0iF5Y= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1702898985; 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=GSd7La5h0M9e2qVPUNvunxZbxK4L5T2M7NX5H+PBXVk=; b=YPrwcFgy+ibVOtXmOaNpyEJ+FwMGoUN734HNZ+I+2/0AkWdHGKjae7oL25phVVncNdcB+0 m0QXjCJEQgju+eyPE75c8xt1inwz+k+GhQ0rllWkIOT31jUykpZ4dwfmaify2gXo4QygS3 9JrlQMfnaqTv8aXM5sqyRkqq8GT4hPU= Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com [209.85.221.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-317-0ZdbjLCGOcC6JHDTMnDzfQ-1; Mon, 18 Dec 2023 06:29:44 -0500 X-MC-Unique: 0ZdbjLCGOcC6JHDTMnDzfQ-1 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-33349915d3cso2267000f8f.3 for ; Mon, 18 Dec 2023 03:29:43 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702898983; x=1703503783; h=content-transfer-encoding:in-reply-to:organization:autocrypt:from :references:cc:to:content-language:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=GSd7La5h0M9e2qVPUNvunxZbxK4L5T2M7NX5H+PBXVk=; b=ZbJ4YZrRnEmFBcpEsL8QayRK/3ZBR+htNL3s9daFivMRXWTjAQ/aTdCZ+6O785Zkl/ QcQTO9snt3hHdGFLxriGOtL6wqqO7ewvMQcOSY3YMkW2fRfAl0842h1+edyycLPinkVX xfdtPOxnaaMk92YSUEtDdsqxM5lHShPMnVNVaTvZTgrFZTVnfo6WiVmjDDwNr6JMDPCW NymssiXEMZsXpQB8tCwkDdTTgENWeY/daZXCJ6+NfUphR5BSKs6qiUCQw1egEJ9dqHp3 P82Par8v1oPEEDj1owAfpwxbh00tC1F0ibkRm4vJBOgcY07BQyF88pLuH1JcXtiXmfIy T1xQ== X-Gm-Message-State: AOJu0YztWoQ1LE0CjICpbQhFoISjrViizUB9uIU6PL9D9xPiY3S2FC5C Ooyj4KYAiSK9G92JRmexyDfWvfD+9c9g1qVOh7UdJJJXeVqzd2WPMPwlJnTXZPPu7/jTFoa3DlN /hrQjTp2jRXg= X-Received: by 2002:adf:ef04:0:b0:336:6907:cbb4 with SMTP id e4-20020adfef04000000b003366907cbb4mr472475wro.53.1702898983024; Mon, 18 Dec 2023 03:29:43 -0800 (PST) X-Google-Smtp-Source: AGHT+IFSYs8MX72nGp36XBQBg4VQAgzg9jXe+N+wQBLnawj0g5rPEg6QHYh8Pl/GzzsFyY2vnJR3ZA== X-Received: by 2002:adf:ef04:0:b0:336:6907:cbb4 with SMTP id e4-20020adfef04000000b003366907cbb4mr472462wro.53.1702898982551; Mon, 18 Dec 2023 03:29:42 -0800 (PST) Received: from ?IPV6:2003:cb:c72b:b500:b53e:6e32:1408:27ac? (p200300cbc72bb500b53e6e32140827ac.dip0.t-ipconnect.de. [2003:cb:c72b:b500:b53e:6e32:1408:27ac]) by smtp.gmail.com with ESMTPSA id r8-20020a056000014800b003364360839esm13204369wrx.81.2023.12.18.03.29.41 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 18 Dec 2023 03:29:42 -0800 (PST) Message-ID: <07c3d204-8285-46d2-b7fa-c63800bd7073@redhat.com> Date: Mon, 18 Dec 2023 12:29:40 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 1/4] mm/ksm: add ksm advisor To: Stefan Roesch , kernel-team@fb.com Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, riel@surriel.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20231213182729.587081-1-shr@devkernel.io> <20231213182729.587081-2-shr@devkernel.io> 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: <20231213182729.587081-2-shr@devkernel.io> 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: 7bit X-Rspamd-Queue-Id: 6686E8000A X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: hrzhpirs3d5b93i9paywanayoyiypoy4 X-HE-Tag: 1702898986-936504 X-HE-Meta: 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 GZU+F2gT 823ylfHS380xpFNsFVKneESiCeLwHjUcL1sBijGrclwDF9LvDjiUlLlndfheJOAWoE9JfpLKu6v7VY+GrT9Bxm/7ei6nLZH+aiY9BBXoGB0ACYgBH/5OV1rvtdaA2cY5B9PiuW/5zBAvLhSpZD+9Yz2Hz3NnzyMyOQFzFGAd087OcuiPTGObbVGtHjPZDWVZ1x0y94uATQebNDKP5cFcEv4WrTe56WtAr+/9pBWcdhvoUyzJlfvKkKmFabfMQBE+i9oS054g5c3Fd/QH+6n7wxAF01Pe23r+vlQt6+dgKo9jlZ+616jS8DsaIYIu66iV65JaT+H6FSR+Qe+QmTXjBuT8Am2lcLJ/6jjPV 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 13.12.23 19:27, Stefan Roesch wrote: > This adds the ksm advisor. The ksm advisor automatically manages the > pages_to_scan setting to achieve a target scan time. The target scan > time defines how many seconds it should take to scan all the candidate > KSM pages. In other words the pages_to_scan rate is changed by the > advisor to achieve the target scan time. The algorithm has a max and min > value to: > - guarantee responsiveness to changes > - limit CPU resource consumption > > The respective parameters are: > - ksm_advisor_target_scan_time (how many seconds a scan should take) > - ksm_advisor_max_cpu (maximum value for cpu percent usage) > > - ksm_advisor_min_pages (minimum value for pages_to_scan per batch) > - ksm_advisor_max_pages (maximum value for pages_to_scan per batch) > > The algorithm calculates the change value based on the target scan time > and the previous scan time. To avoid pertubations an exponentially > weighted moving average is applied. > > The advisor is managed by two main parameters: target scan time, > cpu max time for the ksmd background thread. These parameters determine > how aggresive ksmd scans. > > In addition there are min and max values for the pages_to_scan parameter > to make sure that its initial and max values are not set too low or too > high. This ensures that it is able to react to changes quickly enough. > > The default values are: > - target scan time: 200 secs > - max cpu: 70% > - min pages: 500 > - max pages: 30000 > > By default the advisor is disabled. Currently there are two advisors: > none and scan-time. > > Tests with various workloads have shown considerable CPU savings. Most > of the workloads I have investigated have more candidate pages during > startup, once the workload is stable in terms of memory, the number of > candidate pages is reduced. Without the advisor, the pages_to_scan needs > to be sized for the maximum number of candidate pages. So having this > advisor definitely helps in reducing CPU consumption. > > For the instagram workload, the advisor achieves a 25% CPU reduction. > Once the memory is stable, the pages_to_scan parameter gets reduced to > about 40% of its max value. > > Signed-off-by: Stefan Roesch > --- > mm/ksm.c | 161 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 160 insertions(+), 1 deletion(-) > > diff --git a/mm/ksm.c b/mm/ksm.c > index 7efcc68ccc6ea..4f7b71a1f3112 100644 > --- a/mm/ksm.c > +++ b/mm/ksm.c > @@ -21,6 +21,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -248,6 +249,9 @@ static struct kmem_cache *rmap_item_cache; > static struct kmem_cache *stable_node_cache; > static struct kmem_cache *mm_slot_cache; > > +/* Default number of pages to scan per batch */ > +#define DEFAULT_PAGES_TO_SCAN 100 > + > /* The number of pages scanned */ > static unsigned long ksm_pages_scanned; > > @@ -276,7 +280,7 @@ static unsigned int ksm_stable_node_chains_prune_millisecs = 2000; > static int ksm_max_page_sharing = 256; > > /* Number of pages ksmd should scan in one batch */ > -static unsigned int ksm_thread_pages_to_scan = 100; > +static unsigned int ksm_thread_pages_to_scan = DEFAULT_PAGES_TO_SCAN; > > /* Milliseconds ksmd should sleep between batches */ > static unsigned int ksm_thread_sleep_millisecs = 20; > @@ -297,6 +301,155 @@ unsigned long ksm_zero_pages; > /* The number of pages that have been skipped due to "smart scanning" */ > static unsigned long ksm_pages_skipped; > > +/* Don't scan more than max pages per batch. */ > +static unsigned long ksm_advisor_max_pages = 30000; > + > +/* At least scan this many pages per batch. */ > +static unsigned long ksm_advisor_min_pages = 500; > + > +/* Min CPU for scanning pages per scan */ > +static unsigned int ksm_advisor_min_cpu = 10; That will never be modified, right? Either mark it const or just turn it into a define. [...] > +/* > + * The scan time advisor is based on the current scan rate and the target > + * scan rate. > + * > + * new_pages_to_scan = pages_to_scan * (scan_time / target_scan_time) > + * > + * To avoid perturbations it calculates a change factor of previous changes. > + * A new change factor is calculated for each iteration and it uses an > + * exponentially weighted moving average. The new pages_to_scan value is > + * multiplied with that change factor: > + * > + * new_pages_to_scan *= change facor > + * > + * The new_pages_to_scan value is limited by the cpu min and max values. It > + * calculates the cpu percent for the last scan and calculates the new > + * estimated cpu percent cost for the next scan. That value is capped by the > + * cpu min and max setting. > + * > + * In addition the new pages_to_scan value is capped by the max and min > + * limits. > + */ > +static void scan_time_advisor(void) > +{ > + unsigned int cpu_percent; > + unsigned long cpu_time; > + unsigned long cpu_time_diff; > + unsigned long cpu_time_diff_ms; > + unsigned long pages; > + unsigned long per_page_cost; > + unsigned long factor; > + unsigned long change; > + unsigned long last_scan_time; > + unsigned long scan_time; > + > + /* Convert scan time to seconds */ > + scan_time = div_s64(ktime_ms_delta(ktime_get(), advisor_ctx.start_scan), > + MSEC_PER_SEC); > + scan_time = scan_time ? scan_time : 1; > + > + /* Calculate CPU consumption of ksmd background thread */ > + cpu_time = task_sched_runtime(current); > + cpu_time_diff = cpu_time - advisor_ctx.cpu_time; > + cpu_time_diff_ms = cpu_time_diff / 1000 / 1000; > + > + cpu_percent = (cpu_time_diff_ms * 100) / (scan_time * 1000); > + cpu_percent = cpu_percent ? cpu_percent : 1; > + last_scan_time = prev_scan_time(&advisor_ctx, scan_time); I'd simply inline prev_scan_time() here and get rid of it. Whatever you think is best. Acked-by: David Hildenbrand -- Cheers, David / dhildenb