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 CCFC2C2D0CD for ; Wed, 21 May 2025 13:04:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 54E916B007B; Wed, 21 May 2025 09:04:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 500C26B0082; Wed, 21 May 2025 09:04:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3EEF36B0085; Wed, 21 May 2025 09:04:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 1FDF76B007B for ; Wed, 21 May 2025 09:04:09 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id B6D4158E1F for ; Wed, 21 May 2025 13:04:08 +0000 (UTC) X-FDA: 83466932976.09.55372A0 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf18.hostedemail.com (Postfix) with ESMTP id 131E71C0012 for ; Wed, 21 May 2025 13:04:05 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ZX1sukvc; spf=pass (imf18.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=ZX1sukvc; spf=pass (imf18.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 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=1747832646; 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=uLYiXvR2upB5dbdO5aK9jQCyJdLoqER+/JieU8fmX5M=; b=5KE276RxQRgbLiWU0Y36suJlDvKZKvhbzgE5rJTYQ2gu3kytdVNA+NLjYMzN44gS4sme1S oLNXjSShhOS6tljPzSe7XpDEihegTm8oDBwQgMm4SrWRNzAbSwTk/dSFz4MTtbNmFTT8Fa B1dCk0SrFftYvq+QjDioqa90uWe3dU8= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1747832646; a=rsa-sha256; cv=none; b=2WuRr6MXGvWGxrHOMUrjzwhwtdYg6jceejiSNqZ4Ka2Dbrfn5/am0hJ8OazOYtViCsLYoK ahjYNnKmOhUHtpxx0WhYr78ZmjPR3LfYN27Y3DOZB8QR+5DTN9KGvl9v65DTeN7AsuiMOC mfV9Y/9lOLPqq6KQX88HqUHJBBs7Dmg= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1747832645; 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=uLYiXvR2upB5dbdO5aK9jQCyJdLoqER+/JieU8fmX5M=; b=ZX1sukvcE9fQ4S1SKm1ha3Yjkc7nBLCMV5rN7hhE9T/+bMCtpACVmKZNbTp2FeJxTcZ56F +4tny+G1x7yIqIyHb+wh/ThyfFHtIC1k8zcyYEg1IycgwjinpUifkKVenHND7VOUNaA8yo a7rysumiCYKBR3m7Kva2KR4eznlYAsE= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-473-Xt1xq9kAP1qu8jvkOyc2_Q-1; Wed, 21 May 2025 09:04:04 -0400 X-MC-Unique: Xt1xq9kAP1qu8jvkOyc2_Q-1 X-Mimecast-MFC-AGG-ID: Xt1xq9kAP1qu8jvkOyc2_Q_1747832643 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-44059976a1fso28759815e9.1 for ; Wed, 21 May 2025 06:04:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1747832643; x=1748437443; 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=uLYiXvR2upB5dbdO5aK9jQCyJdLoqER+/JieU8fmX5M=; b=VqE+h5eqanVbDpNOtf/cRo031kdKLZVcIYuEI6CihsdWCnMeE1Zr/RmMgmHfoKcngD op0nGDLs25sXA2zQ8yDNiiAK99GRfgw/TQKvDAf/UYqMF5nWkQ+EXPr3nbMVCtSlbzv+ vAlQC+CaNfMoXdOvBTO3KsbAPmGgi/e8z+4j63nF3taGs/AAS6XmceOFa53Cs5Yn5xJg v3/gcweCksvQAYNXeNHznWc1w0V7zSCw4gwOkQVNvSc46zTwMMo7+UGQKS88Rvxb/lKw fK0rb+Qels1RiymjiyiFvGO/Z5hRBRlhkzwk4q8jqOdfz2aVl5WoJPB5vU1qk1aqqixQ +SAQ== X-Forwarded-Encrypted: i=1; AJvYcCXV7Td/FgqD9zQPMy8TR4XoiFZs2kHg3j5JUMbhgGDZqrm0dW5Jd2eyA6MnJ5IDz0dJzYytb2pcDQ==@kvack.org X-Gm-Message-State: AOJu0YwepamtiBJHpieE6ncoIZuOCBAvoU3wm8KOPqu7zs6y356Sr7c1 FS1BIWqhSrjjmr1JqlIN5ih/EQ7r7isgGrPZfNeW254C6znvTu7TB48VzJvcZ0e179X1zI4FBuA fsiBTostvRn9wmEYgN9V080+QEzcLPAdWaC3Tp7Ila89ns09FloRe X-Gm-Gg: ASbGnctKBtKkml0gehHnwZWG6aA/FVrJqnPtq6fsP4OAXUIIgwNaoBXhjeBnVLt9G9M tAbxxT7pvlVYAU5oly4SwFoTsgM28ZrUQfSv1J6g4FfcFbvWRUg+QZ4zVX5pdeVz7yZVqYOx76g ApBR8yBCifMJYejRNosQNb8wiwiIaSC3glpeFthcbsZqmF++CaVmYY6oc3dzgPQ2QtUSHpgSsqV 7zMsMA1Ox1Q6WtwGPvELu4UkODxBGkuvmskU87KkkWTlQy7fMNDPrBFuR4AH31AkT9EChyFZ4ZN rqU9nXEhKyFitr6CcjpwK/ZRzFTEPPzGnnphBmbPE8wldFV6U2hJEt5MOt1NCBD0eRwJO92gzfL 1OJAVUQQWjAZuE1QzE4QoSEeEhBvrMIPvEDuJmlQ= X-Received: by 2002:a05:600c:3f06:b0:43b:ca39:6c75 with SMTP id 5b1f17b1804b1-442fd63c7aemr234724375e9.16.1747832642774; Wed, 21 May 2025 06:04:02 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEQq97nuCAPHqp/2ziYJfPmUt4MlXXMuJzYIz7ZGgDP6Pek7ndHBqtTZCxqduzSztL4Q8FrRQ== X-Received: by 2002:a05:600c:3f06:b0:43b:ca39:6c75 with SMTP id 5b1f17b1804b1-442fd63c7aemr234723475e9.16.1747832642191; Wed, 21 May 2025 06:04:02 -0700 (PDT) Received: from ?IPV6:2003:d8:2f25:9c00:e2c7:6eb5:8a51:1c60? (p200300d82f259c00e2c76eb58a511c60.dip0.t-ipconnect.de. [2003:d8:2f25:9c00:e2c7:6eb5:8a51:1c60]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-447f73d3d6csm70659835e9.19.2025.05.21.06.04.00 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 21 May 2025 06:04:01 -0700 (PDT) Message-ID: <25283dbd-2867-4034-bb16-951e0fb81843@redhat.com> Date: Wed, 21 May 2025 15:04:00 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9] mm/mempolicy: Weighted Interleave Auto-tuning To: Joshua Hahn , gourry@gourry.net, akpm@linux-foundation.org Cc: harry.yoo@oracle.com, ying.huang@linux.alibaba.com, honggyu.kim@sk.com, yunjeong.mun@sk.com, gregkh@linuxfoundation.org, rakie.kim@sk.com, rafael@kernel.org, lenb@kernel.org, dan.j.williams@intel.com, Jonathan.Cameron@huawei.com, dave.jiang@intel.com, horen.chuang@linux.dev, hannes@cmpxchg.org, osalvador@suse.de, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-mm@kvack.org, kernel-team@meta.com References: <20250520141236.2987309-1-joshua.hahnjy@gmail.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: <20250520141236.2987309-1-joshua.hahnjy@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: K4f6szPvlOQBX6lkC9iFuAwuaBia5Rn1eVXoVlVwwNQ_1747832643 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 131E71C0012 X-Stat-Signature: j7x8334xnipfuqhzh36sx5mkb63obwmt X-Rspam-User: X-HE-Tag: 1747832645-148336 X-HE-Meta: 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 u7A/bx1i 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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 20.05.25 16:12, Joshua Hahn wrote: > On machines with multiple memory nodes, interleaving page allocations > across nodes allows for better utilization of each node's bandwidth. > Previous work by Gregory Price [1] introduced weighted interleave, which > allowed for pages to be allocated across nodes according to user-set ratios. > > Ideally, these weights should be proportional to their bandwidth, so > that under bandwidth pressure, each node uses its maximal efficient > bandwidth and prevents latency from increasing exponentially. > > Previously, weighted interleave's default weights were just 1s -- which > would be equivalent to the (unweighted) interleave mempolicy, which goes > through the nodes in a round-robin fashion, ignoring bandwidth information. > > This patch has two main goals: > First, it makes weighted interleave easier to use for users who wish to > relieve bandwidth pressure when using nodes with varying bandwidth (CXL). > By providing a set of "real" default weights that just work out of the > box, users who might not have the capability (or wish to) perform > experimentation to find the most optimal weights for their system can > still take advantage of bandwidth-informed weighted interleave. > > Second, it allows for weighted interleave to dynamically adjust to > hotplugged memory with new bandwidth information. Instead of manually > updating node weights every time new bandwidth information is reported > or taken off, weighted interleave adjusts and provides a new set of > default weights for weighted interleave to use when there is a change > in bandwidth information. > > To meet these goals, this patch introduces an auto-configuration mode > for the interleave weights that provides a reasonable set of default > weights, calculated using bandwidth data reported by the system. In auto > mode, weights are dynamically adjusted based on whatever the current > bandwidth information reports (and responds to hotplug events). > > This patch still supports users manually writing weights into the nodeN > sysfs interface by entering into manual mode. When a user enters manual > mode, the system stops dynamically updating any of the node weights, > even during hotplug events that shift the optimal weight distribution. > > A new sysfs interface "auto" is introduced, which allows users to switch > between the auto (writing 1 or Y) and manual (writing 0 or N) modes. The > system also automatically enters manual mode when a nodeN interface is > manually written to. > > There is one functional change that this patch makes to the existing > weighted_interleave ABI: previously, writing 0 directly to a nodeN > interface was said to reset the weight to the system default. Before > this patch, the default for all weights were 1, which meant that writing > 0 and 1 were functionally equivalent. With this patch, writing 0 is invalid. > > [1] https://lore.kernel.org/linux-mm/20240202170238.90004-1-gregory.price@memverge.com/ > > Suggested-by: Yunjeong Mun > Suggested-by: Oscar Salvador > Suggested-by: Ying Huang > Suggested-by: Harry Yoo > Tested-by: Honggyu Kim > Reviewed-by: Honggyu Kim > Reviewed-by: Harry Yoo > Reviewed-by: Huang Ying > Co-developed-by: Gregory Price > Signed-off-by: Gregory Price > Signed-off-by: Joshua Hahn > --- [...] > -static void iw_table_free(void) > +static void wi_state_free(void) > { > - u8 *old; > + struct weighted_interleave_state *old_wi_state; > > - mutex_lock(&iw_table_lock); > - old = rcu_dereference_protected(iw_table, > - lockdep_is_held(&iw_table_lock)); > - rcu_assign_pointer(iw_table, NULL); > - mutex_unlock(&iw_table_lock); > + mutex_lock(&wi_state_lock); > + > + old_wi_state = rcu_dereference_protected(wi_state, > + lockdep_is_held(&wi_state_lock)); > + if (!old_wi_state) { > + mutex_unlock(&wi_state_lock); > + goto out; > + } > > + rcu_assign_pointer(wi_state, NULL); > + mutex_unlock(&wi_state_lock); Just one nit: if written as: ... rcu_assign_pointer(wi_state, NULL); mutex_unlock(&wi_state_lock); old_wi_state = ... if (old_wi_state) { synchronize_rcu(); kfree(old_wi_state); } kfree(&wi_group->wi_kobj); You can easily avoid the goto. > synchronize_rcu(); > - kfree(old); > + kfree(old_wi_state); > +out: > + kfree(&wi_group->wi_kobj); > } I'll note that this rather unrelated churn (renaming functions + variables) is a bit abd for review as it adds noise. Having that as part of a cleanup patch might have been better. Nothing else jumped at me (did not an in-depth review of the logic) Acked-by: David Hildenbrand -- Cheers, David / dhildenb