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 63188C5475B for ; Fri, 1 Mar 2024 17:00:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A8E2694000D; Fri, 1 Mar 2024 12:00:08 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A3D93940007; Fri, 1 Mar 2024 12:00:08 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8690694000D; Fri, 1 Mar 2024 12:00:08 -0500 (EST) 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 77221940007 for ; Fri, 1 Mar 2024 12:00:08 -0500 (EST) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 2CE8E41431 for ; Fri, 1 Mar 2024 17:00:08 +0000 (UTC) X-FDA: 81849082896.22.C9B9E66 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf23.hostedemail.com (Postfix) with ESMTP id AA271140004 for ; Fri, 1 Mar 2024 17:00:05 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=JLqYvAO3; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf23.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=1709312405; 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=vC0j1pDca94kVzD56XU2b+pEwYKKJvaHqfZ/B4hPaHU=; b=5vDyfhyla4O8d0HlWoviAknO5NjXc5PDaTF0TkMjyb4absV96OSbodQFkahWG5VFdD7o2T CHzX566TuStTEMMsAKQvMlQsEPdcN4OT/VkYeZWM9tE+rgWzS9fFJzGU0vStRCtWRuwKrB 5N2yE68w0dPxMV5Z8K1QFqwUvj+SGJU= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=JLqYvAO3; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf23.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=1709312405; a=rsa-sha256; cv=none; b=p9EfCb5a+ThRoW72rrLQuoe1S6den9xOK34dDs+O6p1ZHWfv9ITT1boHCGolMlbEWbCr5F C4fvFGAEigezUhTvctLzpDeSfwVa7rUsVdyBclfGYJas3VQWuscuNc72fCKaEsxxI2cgjk W5n9MGpaGIjJn0Lq1rPlS6wBfdYW6pc= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709312405; 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=vC0j1pDca94kVzD56XU2b+pEwYKKJvaHqfZ/B4hPaHU=; b=JLqYvAO3dsUSCm7kQw0+Vwl9cdEALDCiZpKZcW9CUKDI7fvixqg/uj8LUAM7PTxWIs9pkL B+dPanCXjMMO4kDIq3d+yBKvj92pbnp8B2X6gNiZhEXJLGNkTHhjgHDBu6xrUHMNraOl0r 0LowNOCK79cN0+z4l2Gp3++e46ZohGE= Received: from mail-wr1-f72.google.com (mail-wr1-f72.google.com [209.85.221.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-281-qg3OhwXINFyMnjfOndKwbQ-1; Fri, 01 Mar 2024 12:00:03 -0500 X-MC-Unique: qg3OhwXINFyMnjfOndKwbQ-1 Received: by mail-wr1-f72.google.com with SMTP id ffacd0b85a97d-33dcd5d117fso1133724f8f.1 for ; Fri, 01 Mar 2024 09:00:03 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1709312402; x=1709917202; 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=vC0j1pDca94kVzD56XU2b+pEwYKKJvaHqfZ/B4hPaHU=; b=LOcoCVNFdQYLOvTvTKPYz1lmPXt3rQdIKa4fexP/5GNfjPNxVMlVSbdW1KOjpiVd0p 4kTmLGHk2p+nkFb3DYTw2iyE4wcgrlZX9zcqVqKLJaXxDJP0GmZKfILlIz+11Ew5B+fo dwFfAnDfxD2t4coeEAFKCbSP2kEB3NWlraCzhZjVMmxY75hk/PjFzTkjywJEbR12TeFF vY954fHScYRts/605Sz1rEKB7+lz0bPqBXBsit9JCx2CRXcrEUmo9m5cVS3ZjT42JMlN zE/QuEFN+m0AM3oCTC1/zeqBuqNxJWYsa+j5pCThTQQ22LJuDHFj6W0bNYJ8HXoEl5/C UyPQ== X-Forwarded-Encrypted: i=1; AJvYcCWzdQ4BMlMejuBjYD7VWiNYeCmpNoIxMjTtnT9tHSS3vz8l02hx4co6Co8rJM3jaXaFR+e86m29bKpI8gvwnJvKgpY= X-Gm-Message-State: AOJu0YweM16zwZX1G8kDCkIEjfkIGxtJ7ZmhQ/udUx7UWTJFgQT4cvAY L6Eki8ZvYgT2zji7BaqtC2FNv57+ykZrBO750z+wrtvYSiJpy2dIOOW3fRsJsMNPxkYCsIpa9v9 BpjC5VctvAx/6HjstFnziNpN/bgYZQH2JfZbL+fZBe5Gi414l X-Received: by 2002:adf:cc07:0:b0:33e:11d7:1a95 with SMTP id x7-20020adfcc07000000b0033e11d71a95mr3304521wrh.27.1709312402481; Fri, 01 Mar 2024 09:00:02 -0800 (PST) X-Google-Smtp-Source: AGHT+IFYnzp3dw9AckN62AJlZtm/FXCwjJTKZL+PJQjC/qnNz+fG+crGDHIqjyPeWe9oHBKdvoouUA== X-Received: by 2002:adf:cc07:0:b0:33e:11d7:1a95 with SMTP id x7-20020adfcc07000000b0033e11d71a95mr3304493wrh.27.1709312402127; Fri, 01 Mar 2024 09:00:02 -0800 (PST) Received: from ?IPV6:2003:cb:c713:3200:77d:8652:169f:b5f7? (p200300cbc7133200077d8652169fb5f7.dip0.t-ipconnect.de. [2003:cb:c713:3200:77d:8652:169f:b5f7]) by smtp.gmail.com with ESMTPSA id jn3-20020a05600c6b0300b004128e903b2csm8893123wmb.39.2024.03.01.09.00.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 01 Mar 2024 09:00:01 -0800 (PST) Message-ID: Date: Fri, 1 Mar 2024 18:00:00 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/4] mm: swap: Remove CLUSTER_FLAG_HUGE from swap_cluster_info:flags To: Ryan Roberts , Matthew Wilcox Cc: Andrew Morton , Huang Ying , Gao Xiang , Yu Zhao , Yang Shi , Michal Hocko , Kefeng Wang , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <6541e29b-f25a-48b8-a553-fd8febe85e5a@redhat.com> <2934125a-f2e2-417c-a9f9-3cb1e074a44f@redhat.com> <049818ca-e656-44e4-b336-934992c16028@arm.com> <4a73b16e-9317-477a-ac23-8033004b0637@arm.com> <1195531c-d985-47e2-b7a2-8895fbb49129@redhat.com> <5ebac77a-5c61-481f-8ac1-03bc4f4e2b1d@arm.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: 7bit X-Rspamd-Queue-Id: AA271140004 X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: sp9ynzsmo9x9h1g9ophsxbh5pqgpdopu X-HE-Tag: 1709312405-823396 X-HE-Meta: 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 V5Bhwkql 7C6gAH4UPDFWpN3m85eV9se/FjCHqaYvAiJJoSpCbuKj3qHsBnXpKg9UkfVvbPRevcwcOXF1QrTn+9MHbPFQjBb2xisc0PVPQYv/OYcuOAS14zqevPzeRZIWYNy3EKbrEnRV8/8C05vFVeRLMnitnZXgog2sC6MGD7nf+fqSslp/FncfJSH7gF8xDL8qoHrfm9q0TM0G+8uRUk3eRBK/cd8jjkQ== 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 01.03.24 17:44, Ryan Roberts wrote: > On 01/03/2024 16:31, Matthew Wilcox wrote: >> On Fri, Mar 01, 2024 at 04:27:32PM +0000, Ryan Roberts wrote: >>> I've implemented the batching as David suggested, and I'm pretty confident it's >>> correct. The only problem is that during testing I can't provoke the code to >>> take the path. I've been pouring through the code but struggling to figure out >>> under what situation you would expect the swap entry passed to >>> free_swap_and_cache() to still have a cached folio? Does anyone have any idea? >>> >>> This is the original (unbatched) function, after my change, which caused David's >>> concern that we would end up calling __try_to_reclaim_swap() far too much: >>> >>> int free_swap_and_cache(swp_entry_t entry) >>> { >>> struct swap_info_struct *p; >>> unsigned char count; >>> >>> if (non_swap_entry(entry)) >>> return 1; >>> >>> p = _swap_info_get(entry); >>> if (p) { >>> count = __swap_entry_free(p, entry); >>> if (count == SWAP_HAS_CACHE) >>> __try_to_reclaim_swap(p, swp_offset(entry), >>> TTRS_UNMAPPED | TTRS_FULL); >>> } >>> return p != NULL; >>> } >>> >>> The trouble is, whenever its called, count is always 0, so >>> __try_to_reclaim_swap() never gets called. >>> >>> My test case is allocating 1G anon memory, then doing madvise(MADV_PAGEOUT) over >>> it. Then doing either a munmap() or madvise(MADV_FREE), both of which cause this >>> function to be called for every PTE, but count is always 0 after >>> __swap_entry_free() so __try_to_reclaim_swap() is never called. I've tried for >>> order-0 as well as PTE- and PMD-mapped 2M THP. >> >> I think you have to page it back in again, then it will have an entry in >> the swap cache. Maybe. I know little about anon memory ;-) > > Ahh, I was under the impression that the original folio is put into the swap > cache at swap out, then (I guess) its removed once the IO is complete? I'm sure > I'm miles out... what exactly is the lifecycle of a folio going through swap out? I thought with most (disk) backends you will add it to the swapcache and leave it there until there is actual memory pressure. Only then, under memory pressure, you'd actually reclaim the folio. You can fault it back in from the swapcache without having to go to disk. That's how you can today end up with a THP in the swapcache: during swapin from disk (after the folio was reclaimed) you'd currently only get order-0 folios. At least that was my assumption with my MADV_PAGEOUT testing so far :) -- Cheers, David / dhildenb