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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B8CAECCD187 for ; Tue, 14 Oct 2025 07:24:53 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 0D5608E00C4; Tue, 14 Oct 2025 03:24:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0AC498E0005; Tue, 14 Oct 2025 03:24:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EDD958E00C4; Tue, 14 Oct 2025 03:24:52 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id DCE188E0005 for ; Tue, 14 Oct 2025 03:24:52 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 9A4935B07F for ; Tue, 14 Oct 2025 07:24:52 +0000 (UTC) X-FDA: 83995882824.24.3513189 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf24.hostedemail.com (Postfix) with ESMTP id 1990B180003 for ; Tue, 14 Oct 2025 07:24:49 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=imjZItOE; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf24.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=1760426690; 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=dWVRMEm11rNZj8S0erLvsCvAhmyyCMMtTFXiGsJH80c=; b=lNwtgtN+Ik5G24p3YsfauQ7vMGLGH0c8XzstujgzIw7FrxqfOA3vfUvRMzMU+Jpmuz1kxt padAcrc1PFebWFbStoxa196ZXLszy64L82firlVTIDKTcXmgWCFLF8HP6ebvMN/rh1fYQY 5G3ApHrcbxIMg4nA9XHPGID2CXCzdA0= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=imjZItOE; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf24.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=1760426690; a=rsa-sha256; cv=none; b=Xv/4vhlQH0cUfS7BVSivxfsrihf5TtKxEBcU0k+CRb8fuVTLfKnYd3WKHX5X7sgLW7BjRs ++S6OeEF/CchKhwwyokjakIj+ZXR9i7G5FxEMKQsirjDSBdgNmVaC6QhFrBwL8oeKjALpw nsXdHTKx5YXctS4QVkZjt2ULKzsrNU4= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1760426689; 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=dWVRMEm11rNZj8S0erLvsCvAhmyyCMMtTFXiGsJH80c=; b=imjZItOEGATXEmry0y0Z/BsPsHY8fnrUrSsGZsDKyX1JnqxHFKRyxIcXd6may0o8rfoB10 eAXnBHPOI6A3ZNT9CMxpxDjDHBWauE+RDDdGjOIn89Vn6rFyjsUftjGHiv8krKiLWUG3e1 PSrkBhFPrRS5+qp8QolT4ur73ELZKd4= 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-633-lNTmD4azMqmgmgsf_kNyvg-1; Tue, 14 Oct 2025 03:24:47 -0400 X-MC-Unique: lNTmD4azMqmgmgsf_kNyvg-1 X-Mimecast-MFC-AGG-ID: lNTmD4azMqmgmgsf_kNyvg_1760426686 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-46e3dcb36a1so38797605e9.2 for ; Tue, 14 Oct 2025 00:24:47 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760426686; x=1761031486; h=content-transfer-encoding:in-reply-to: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=dWVRMEm11rNZj8S0erLvsCvAhmyyCMMtTFXiGsJH80c=; b=aGAYfBtHoBNk/zz4juiuthn46WiGYCmjF2l3dt1D0arHBUesbngp8HZipVO2aH2/6q hMq/LEPGnlVqtb3OnADCwSSnELzjWwfrgxeYUS7Vt3ZinDXH25LXaR61mFFWW4EsnzR5 fMuhLNGL/IDBXrVDtuItqBWbId6CvYA/0ucktsZWayLirzIs+cdSZuSW3pp+1sIVuW+z xECCChStlFywBgUMyeWFQJxG3u9CTcSU+4sLi9Zj+vDJ+5FFpZ1eqbC4uKli17so9KrF R4/u+ygbpOlXXck7RN/PjU3CX3tPw6f/BA4GeFzc/vCqk90L/WhbBMXqPMnZkLQwQ7E/ Xdfg== X-Forwarded-Encrypted: i=1; AJvYcCVC9/sv4jnAm0NBGvYKm5Lq5DXCVo6HCmmtc/1siYLYQ1+DaCwIN5YsQk1npecpdj9Jf+xI/k6qtg==@kvack.org X-Gm-Message-State: AOJu0YzyR/ZYhIZJj+8viJT0tX1T4/YoCAXkWeGcIkf3uydVL3YDOF8l 9ONHq/W0DNPKZciIA4zVI26P+GPW7lEI5f2YRQb+8+uDaR02dnElYm9PoxpfPuZFhAnIdmBnY33 OcqOQOE8wg11z8M9w0oJeRMdOQo15US4yKgZYYkdA1BkJiC0omzJb X-Gm-Gg: ASbGncthaTpw7RB/JpGd6RxPVEHCOF/NwmGiCYxf/ONubz6+xS0yey3xz5xh6cajF4V V21074JhG746NnbbMjvy01CJjt3rm7zXGo/qKKmaQV/3vQE6IQQtAzgP7K7aekt0XXPfjfLBMqO GBtVyFmimgR3A1LMe+kPpHWh8rCoPOKdj4xuUUMVD25YzTapDJ8ADfj8WX0CHnqmOXCd8XssQ0D Z6iuuEQVzMgmez94NOplZdtfjwZb6zGYwtl8Bs345/dC1Y+dzTPFPy0FgLUK+YsKxLMGNOrHAVd BJF4ywdBP6lGvCyoyXiJ8LfMPvkArmJ3PaSqfdUWG2DQyUOj1wIlcP/pvZWw2rL8emNYO6ilew= = X-Received: by 2002:a05:600c:34c5:b0:46e:3d5a:d15d with SMTP id 5b1f17b1804b1-46fa9b064bcmr146297115e9.26.1760426686135; Tue, 14 Oct 2025 00:24:46 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGC8FI5kSvwYT/CgzZ/QfWD6LZL5gZynJwlCP6Ew1X9IcwxCSDa9KcsHDZPMzIBrxy028sWwg== X-Received: by 2002:a05:600c:34c5:b0:46e:3d5a:d15d with SMTP id 5b1f17b1804b1-46fa9b064bcmr146296865e9.26.1760426685693; Tue, 14 Oct 2025 00:24:45 -0700 (PDT) Received: from ?IPV6:2a09:80c0:192:0:5dac:bf3d:c41:c3e7? ([2a09:80c0:192:0:5dac:bf3d:c41:c3e7]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-46fb4982b30sm222538135e9.6.2025.10.14.00.24.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 14 Oct 2025 00:24:45 -0700 (PDT) Message-ID: <2a48209c-13a4-4c55-b35a-6aefd4ae92f3@redhat.com> Date: Tue, 14 Oct 2025 09:24:44 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/3] mm: huge_memory: use prot_numa_skip() for pmd folio To: Kefeng Wang , Andrew Morton , Lorenzo Stoakes , linux-mm@kvack.org Cc: Zi Yan , Baolin Wang , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Liam.Howlett@oracle.com References: <20251013121536.2373249-1-wangkefeng.wang@huawei.com> <20251013121536.2373249-4-wangkefeng.wang@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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: V1tJRG5zmTo-N0PWm-RzGtF6a4Y7PBOeX1p2V_EQ4sU_1760426686 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: 1990B180003 X-Rspamd-Server: rspam03 X-Stat-Signature: rb3nwd7a38pqoja3qrfcionqxqw51ftj X-HE-Tag: 1760426689-802005 X-HE-Meta: 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 sC6Lv2na 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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 14.10.25 08:10, Kefeng Wang wrote: > > > On 2025/10/13 23:58, David Hildenbrand wrote: >> On 13.10.25 14:15, Kefeng Wang wrote: >>> The prot_numa_skip() checks should be suitable for pmd folio too, >>> which helps to avoid unnecessary pmd change and folio migration >>> attempts. >>> >>> Signed-off-by: Kefeng Wang >>> --- >>>   mm/huge_memory.c | 21 +++++++-------------- >>>   mm/internal.h    |  2 ++ >>>   mm/mprotect.c    |  2 +- >>>   3 files changed, 10 insertions(+), 15 deletions(-) >>> >>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >>> index 1b81680b4225..feca5a19104a 100644 >>> --- a/mm/huge_memory.c >>> +++ b/mm/huge_memory.c >>> @@ -2395,8 +2395,7 @@ int change_huge_pmd(struct mmu_gather *tlb, >>> struct vm_area_struct *vma, >>>   #endif >>>       if (prot_numa) { >>> -        struct folio *folio; >>> -        bool toptier; >>> +        int target_node = NUMA_NO_NODE; >>>           /* >>>            * Avoid trapping faults against the zero page. The read-only >>>            * data is likely to be read-cached on the local CPU and >>> @@ -2408,19 +2407,13 @@ int change_huge_pmd(struct mmu_gather *tlb, >>> struct vm_area_struct *vma, >>>           if (pmd_protnone(*pmd)) >>>               goto unlock; >>> -        folio = pmd_folio(*pmd); >>> -        toptier = node_is_toptier(folio_nid(folio)); >>> -        /* >>> -         * Skip scanning top tier node if normal numa >>> -         * balancing is disabled >>> -         */ >>> -        if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_NORMAL) && >>> -            toptier) >>> -            goto unlock; >>> +        /* Get target node for single threaded private VMAs */ >>> +        if (!(vma->vm_flags & VM_SHARED) && >>> +            atomic_read(&vma->vm_mm->mm_users) == 1) >>> +            target_node = numa_node_id(); >> >> Wondering if we should move that hunk into prot_numa_skip() as well. >> >> I'd assume numa_node_id() is not particularly expensive? > > There is a atomic read, it may be expensive for 512 times atomic read > for change_pte_range(). Note that atomic reads are usually just ordinary reads. IIRC, the relevant code is cpu_to_node(raw_smp_processor_id()) And raw_smp_processor_id() is mostly either "current_thread_info()->cpu" or "this_cpu_read(cpu_number)". But yeah, we can leave it as is for now and cache it in the caller. -- Cheers David / dhildenb