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 0C8C9C4829B for ; Mon, 12 Feb 2024 09:05:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 956E46B006E; Mon, 12 Feb 2024 04:05:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E0FB6B0071; Mon, 12 Feb 2024 04:05:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7343C6B0074; Mon, 12 Feb 2024 04:05:09 -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 5A2306B0071 for ; Mon, 12 Feb 2024 04:05:09 -0500 (EST) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 28E5616062A for ; Mon, 12 Feb 2024 09:05:09 +0000 (UTC) X-FDA: 81782567538.21.1DC75D2 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf22.hostedemail.com (Postfix) with ESMTP id C1BB5C000D for ; Mon, 12 Feb 2024 09:05:06 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=cvR8xfjd; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf22.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=1707728706; 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=vVWqrcbvT6Jgui2UzjnuWOOc25jjYiOFrNNZqedfwL8=; b=jwYfw1aFwFYqidP+KYg3TtmLj+8peQcI/TetFNxLMUxv3iIcsdaL4YIp9MdqfUFyGP6AjX e5M37rZes5UPdz59xJ/uTbZJDM0GFu4aBKk07CuwSJBH3z/s5hKSoqX7wFsN5jVsKJA1WK A7gUDY23QYH4fLBcRenziPN2UEa44Uo= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=cvR8xfjd; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf22.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=1707728706; a=rsa-sha256; cv=none; b=dZKbU+TgjHv/VXy5C/e1GQktAfIJ7TOt3r5OtVboswRE4oHrPb5QPf+8+vu//atH9nfOr8 TPNCZSjorT+uYoyM2RJ2o4RNXsQ40AYn8lqjKkcv7v1CrcxRNqcgaOfRIFWpBbUqunrRNw cxMCbWjqfJ0EJ5eh/mw4h/FQWvTvMGc= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1707728706; 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=vVWqrcbvT6Jgui2UzjnuWOOc25jjYiOFrNNZqedfwL8=; b=cvR8xfjdX3Plurxs95HCnMnscjDr5OXV+mTL//te49z7gAUYaArvQUYczhnd0PJTgeVDXP vqAlVX0C7RnE4wxwVedmxpjZg/fY4YOfxqD5YVVNhekWbxMEPnX5Fwo5rhP3L8DfWqWgr+ 35/LRREoJQs+zgICfAAj1hYRLvjjusw= Received: from mail-lf1-f71.google.com (mail-lf1-f71.google.com [209.85.167.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-526-sfKC-T3zNj2Nc8_M_S_ynQ-1; Mon, 12 Feb 2024 04:05:04 -0500 X-MC-Unique: sfKC-T3zNj2Nc8_M_S_ynQ-1 Received: by mail-lf1-f71.google.com with SMTP id 2adb3069b0e04-511490b3d50so2714685e87.0 for ; Mon, 12 Feb 2024 01:05:04 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1707728703; x=1708333503; 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=vVWqrcbvT6Jgui2UzjnuWOOc25jjYiOFrNNZqedfwL8=; b=q51vzpu96kkh1xZzbPZn3sCMj9F1+ybk2WojXdumDbgSqEeaxljkUorprw+058ypj2 egYswZEKxcd2B60KHFUu5HawoJ1btWxCYfx3Gb92mAKn1Wf5pQSM4m6l+rKlhLG5KIEN f6JMGJMrN5L5soTU2vZ0K4R1r1/rCQ+PH9twDp/f0pSJCJKsd7xR5akS/H000/gq/TTB 0S42y4FN5jo02s3W0cSX65DFmlrbXTlrCNiYDsamPjmZZ5rzRLjztkVhLNu+vTzLbPax 0edh5qC2Urd/5pDaJb2pGkeB92cVzltkwtoQ//CD/3F7pB1cwH/u4ZfiZeRmSycj+fK5 tHEA== X-Gm-Message-State: AOJu0YxbQyHPk9f4gJhu9/lfTUGWQxu031p1EpgMrShyw+B9kEoXdUR+ qJi9lAF4SsVD9P9TZ9gklZhiXqZ549RbhEL9fmig5RZT+r6q8cgCnFOJkW2mGHfNU4H3Snz/3fY MSSEexeAQsnm/mf7Dnd6TUh8t4PO+oCfWVRiEmZ4v4Sr76pUK X-Received: by 2002:a05:6512:3244:b0:511:737d:6619 with SMTP id c4-20020a056512324400b00511737d6619mr3394151lfr.0.1707728703075; Mon, 12 Feb 2024 01:05:03 -0800 (PST) X-Google-Smtp-Source: AGHT+IFfFLQYPUUppRMxcfUxxOUmGhf/M5SoV+8fc9TSIRJaSdT1xW8fFFDrfDFym51J8jpGjzoT0g== X-Received: by 2002:a05:6512:3244:b0:511:737d:6619 with SMTP id c4-20020a056512324400b00511737d6619mr3394139lfr.0.1707728702691; Mon, 12 Feb 2024 01:05:02 -0800 (PST) X-Forwarded-Encrypted: i=1; AJvYcCWJyAt/qEcy62QbqvMJ5ibo9vbgg01k8AjEqOoYQacEQ6CotrHtRCBlNLIsi2PAYWJ9Uh8KjelI8qXm6IMriqOf/eOcZyNzLnAqctf4nciCHVpKYtxEDQ/l6Jxo490uj+ivb3X+awk2yGIrXFS5x1LB9RmUfCWz5LTOhgjwZWz58mPwj/qBxQ== Received: from ?IPV6:2003:cb:c730:2200:7229:83b1:524e:283a? (p200300cbc7302200722983b1524e283a.dip0.t-ipconnect.de. [2003:cb:c730:2200:7229:83b1:524e:283a]) by smtp.gmail.com with ESMTPSA id u3-20020ac258c3000000b005115ea2c301sm799410lfo.49.2024.02.12.01.05.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 12 Feb 2024 01:05:02 -0800 (PST) Message-ID: Date: Mon, 12 Feb 2024 10:05:01 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] fs/proc/task_mmu: Add display flag for VM_MAYOVERLAY To: Anshuman Khandual , Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <20240208084805.1252337-1-anshuman.khandual@arm.com> <20240208124035.1c96c256d6e8c65f70b18675@linux-foundation.org> <2e7496af-0988-49fb-9582-bf6a94f08198@redhat.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: jr3hfspefwjiaa5q5yzro1oe75q14seu X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: C1BB5C000D X-HE-Tag: 1707728706-378502 X-HE-Meta: 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 Y40XYrm3 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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 12.02.24 03:00, Anshuman Khandual wrote: > > On 2/10/24 04:01, David Hildenbrand wrote: >> On 08.02.24 21:40, Andrew Morton wrote: >>> On Thu, 8 Feb 2024 17:48:26 +0100 David Hildenbrand wrote: >>> >>>> On 08.02.24 09:48, Anshuman Khandual wrote: >>>>> VM_UFFD_MISSING flag is mutually exclussive with VM_MAYOVERLAY flag as they >>>>> both use the same bit position i.e 0x00000200 in the vm_flags. Let's update >>>>> show_smap_vma_flags() to display the correct flags depending on CONFIG_MMU. >>>>> >>>>> Cc: Andrew Morton >>>>> Cc: David Hildenbrand >>>>> Cc: linux-kernel@vger.kernel.org >>>>> Cc: linux-fsdevel@vger.kernel.org >>>>> Signed-off-by: Anshuman Khandual >>>>> --- >>>>> This applies on v6.8-rc3 >>>>> >>>>>    fs/proc/task_mmu.c | 4 ++++ >>>>>    1 file changed, 4 insertions(+) >>>>> >>>>> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c >>>>> index 3f78ebbb795f..1c4eb25cfc17 100644 >>>>> --- a/fs/proc/task_mmu.c >>>>> +++ b/fs/proc/task_mmu.c >>>>> @@ -681,7 +681,11 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma) >>>>>            [ilog2(VM_HUGEPAGE)]    = "hg", >>>>>            [ilog2(VM_NOHUGEPAGE)]    = "nh", >>>>>            [ilog2(VM_MERGEABLE)]    = "mg", >>>>> +#ifdef CONFIG_MMU >>>>>            [ilog2(VM_UFFD_MISSING)]= "um", >>>>> +#else >>>>> +        [ilog2(VM_MAYOVERLAY)]    = "ov", >>>>> +#endif /* CONFIG_MMU */ >>>>>            [ilog2(VM_UFFD_WP)]    = "uw", >>>>>    #ifdef CONFIG_ARM64_MTE >>>>>            [ilog2(VM_MTE)]        = "mt", >>>> >>>> Reviewed-by: David Hildenbrand >>> >>> I'm thinking >>> >>> Fixes: b6b7a8faf05c ("mm/nommu: don't use VM_MAYSHARE for MAP_PRIVATE mappings") >>> Cc: >> >> I'm having a hard time believing that anybody that runs a !MMU kernel would actually care about this bit being exposed as "ov" instead of "uw". >> >> So in my thinking, one could even update Documentation/filesystems/proc.rst to just mention that "uw" on !MMU is only used for internal purposes. >> >> But now, I actually read what that structure says: >> >> "Don't forget to update Documentation/ on changes." >> >> So, let's look there: Documentation/filesystems/proc.rst >> >> "Note that there is no guarantee that every flag and associated mnemonic will be present in all further kernel releases. Things get changed, the flags may be vanished or the reverse -- new added. Interpretation of their meaning might change in future as well. So each consumer of these flags has to follow each specific kernel version for the exact semantic. >> >> This file is only present if the CONFIG_MMU kernel configuration option is enabled." >> >> And in fact >> >> $ git grep MMU fs/proc/Makefile >> fs/proc/Makefile:proc-$(CONFIG_MMU)     := task_mmu.o > > Ahh! you are right, completely missed that. > >> >> >> So I rewoke my RB, this patch should be dropped and was never even tested unless I am missing something important. > > Fair enough, let's drop this patch. I found this via code inspection while > looking into VM_UFFD_MISSING definition, booted with default configs which > has CONFIG_MMU enabled. But this was an oversight, my bad. > No worries, NUMMU is just absolutely weird :) -- Cheers, David / dhildenb