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 CD73EC10F1A for ; Tue, 7 May 2024 18:38:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4F7776B0096; Tue, 7 May 2024 14:38:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4A7AE6B009A; Tue, 7 May 2024 14:38:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 348396B009C; Tue, 7 May 2024 14:38:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 16FE06B0096 for ; Tue, 7 May 2024 14:38:03 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id B69BE160D04 for ; Tue, 7 May 2024 18:38:02 +0000 (UTC) X-FDA: 82092459204.09.52FD50A Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf17.hostedemail.com (Postfix) with ESMTP id 584194000C for ; Tue, 7 May 2024 18:38:00 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Cbk1Tso9; spf=pass (imf17.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1715107080; 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=dByjWaf8mzPMt0+yCIuC+Vh6WT0q2RmuMIu0cTN5Lo4=; b=kTxcWUWna2W4qP63va9C03uWevQcKWOb6jfI8Xq7yHjGJMPQ0Wv4FcluUqIdLO4aGw1tnP JDCDpOwYvI2sJMLA6TNal/7n7ayt+vbRKYoG1lyHPhwPcb9wcD0c1H9wFfppdyVgNeFGJl k/3zFpy/L2EeFPK0n8fkAgUTpy6WKD8= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1715107080; a=rsa-sha256; cv=none; b=tUS29RYb7kvnT8wBMwbNakryd/+5/b9llaOWqu24Y98KdMP9Q77Gc+vqx5JUtNO2DQTO7W MyafvMX1XhzhYgUrFVaHXMA8iT/1jDTKu11J9czzaIOAeC4m4UPrbCPzE8sIiqH13JLfqI uMiJ+PQ6TceVyYf5qvqI1AwJU9AeCg8= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Cbk1Tso9; spf=pass (imf17.hostedemail.com: domain of david@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1715107079; 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=dByjWaf8mzPMt0+yCIuC+Vh6WT0q2RmuMIu0cTN5Lo4=; b=Cbk1Tso9QHaTtr7b35Nm3UVrkGyf/8RGWJQ5hi5aKGo3oAqBsXszMg31zo8mnkx51lt4or jDf2hssGFqbu5wOxgsSdiCdD9j3PHAw8mt5SW85yM8FMIaVE/Eh1EJQeYSURWV3Za+OOlq 1/ZD0pfbVYQR+NH+VrpBdidcip1ByBE= 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-418-bS0Zjf6NNAmM1TEWzZxR-g-1; Tue, 07 May 2024 14:37:58 -0400 X-MC-Unique: bS0Zjf6NNAmM1TEWzZxR-g-1 Received: by mail-wr1-f70.google.com with SMTP id ffacd0b85a97d-34d7e948a41so2177148f8f.1 for ; Tue, 07 May 2024 11:37:58 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1715107077; x=1715711877; 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=dByjWaf8mzPMt0+yCIuC+Vh6WT0q2RmuMIu0cTN5Lo4=; b=NFjoVbn38kYhnrwUkjNHb3CFzNGLt4psZI51Do3X1TBYyDWbb4uXt5rGyDYdiNa6zk P6Ja/iVtuWnEQhmI63fe23SZtW3I1lInFHKTHTzqBncuhPaT9akedqC+0Xcj7lW9DSMB KOOKsyvymvEqM09XVh6Nt4OshN9Mzzz5VCMcXwr65rg9q7OFPGMfY8e5Ns67EKz8TWaa VTSSdK8irNngRS7+MBiMCnV8YU16ciYj8oZl22XsFQ1/13RgW60VVjsERbE+q0Od96oO +Y+LBh5n9Xmx4A/ldgcSAhMvbmq4hN2dblhUgwSsWAO9cgTGNwpVGZtHuKvfrzFxIjEk 6r2w== X-Forwarded-Encrypted: i=1; AJvYcCUr4SSVJWM2uOaheipCl/xR82kG7uAdHfgW/LkHgsmGFHog6gdVwHm1ylpob/yJed72TklANm3n5PubqzQsRLlwGR8= X-Gm-Message-State: AOJu0Yz7vs7E+s4GIkSddFl2hm0CdEzTnPwzxvUTNzv69wYIFBQ4wHzn rUv4yi56IxcaYRR84dt/ULjoAHcHRhMrSf5fZXCqaKVrFAiy2QeHqCOFRLEAhAN3xq4UR6lZNSW amUlxDNdKYrG4wHo2onhasu5OWUF6tQ3xkYcYZ8xtgrzOHsKl X-Received: by 2002:adf:fb07:0:b0:343:ef64:e0fd with SMTP id ffacd0b85a97d-34fcb2b47damr417501f8f.52.1715107077048; Tue, 07 May 2024 11:37:57 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEGDtOsF1Bfynr+PIaRF8blpTX8UglX76GcZ2uhsd5D7K1V+iZLMz0Ndvk1is+asuAJVabLLQ== X-Received: by 2002:adf:fb07:0:b0:343:ef64:e0fd with SMTP id ffacd0b85a97d-34fcb2b47damr417487f8f.52.1715107076579; Tue, 07 May 2024 11:37:56 -0700 (PDT) Received: from ?IPV6:2003:cb:c744:b500:3f9d:130d:ea00:afc7? (p200300cbc744b5003f9d130dea00afc7.dip0.t-ipconnect.de. [2003:cb:c744:b500:3f9d:130d:ea00:afc7]) by smtp.gmail.com with ESMTPSA id g18-20020a5d5412000000b00346bda84bf9sm13530476wrv.78.2024.05.07.11.37.55 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 07 May 2024 11:37:56 -0700 (PDT) Message-ID: <42a18f08-99a5-4bb0-8a1d-771549cac046@redhat.com> Date: Tue, 7 May 2024 20:37:55 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mm-unstable] mm: rmap: abstract updating per-node and per-memcg stats To: Yosry Ahmed Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20240506211333.346605-1-yosryahmed@google.com> <1a408ed1-7e81-457e-a205-db274b4d6b78@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: 9ri6eehhah6g7isk79m5nba8as71xp5a X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 584194000C X-HE-Tag: 1715107080-629185 X-HE-Meta: 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 JJKVrO2H 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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 07.05.24 17:54, Yosry Ahmed wrote: > On Tue, May 7, 2024 at 1:52 AM David Hildenbrand wrote: >> >> On 06.05.24 23:13, Yosry Ahmed wrote: >>> A lot of intricacies go into updating the stats when adding or removing >>> mappings: which stat index to use and which function. Abstract this away >>> into a new static helper in rmap.c, __folio_mod_stat(). >>> >>> This adds an unnecessary call to folio_test_anon() in >>> __folio_add_anon_rmap() and __folio_add_file_rmap(). However, the folio >>> struct should already be in the cache at this point, so it shouldn't >>> cause any noticeable overhead. >> >> Depending on the inlining, we might have more branches that could be avoided >> (especially in folio_add_new_anon_rmap()). >> >> [the rmap code is more performance-sensitive and relevant than you might think] > > I thought about making the helper __always_inline. Would that be better? Let's leave it like that. I might do some actual measurements to see if it makes a difference at all. >>> >>> No functional change intended. >>> >>> Signed-off-by: Yosry Ahmed >>> --- >>> >>> This applies on top of "mm: do not update memcg stats for >>> NR_{FILE/SHMEM}_PMDMAPPED": >>> https://lore.kernel.org/lkml/20240506192924.271999-1-yosryahmed@google.com/ >>> >>> David, I was on the fence about adding a Suggested-by here. You did >>> suggest adding a helper, but the one with the extra folio_test_anon() >>> was my idea and I didn't want to blame it on you. So I'll leave this up >>> to you :) >> >> :) fair enough! It's a clear improvement to readability. >> >> [...] >>> >>> - if (nr_pmdmapped) { >>> - /* NR_{FILE/SHMEM}_PMDMAPPED are not maintained per-memcg */ >>> - if (folio_test_anon(folio)) >>> - __lruvec_stat_mod_folio(folio, NR_ANON_THPS, -nr_pmdmapped); >>> - else >>> - __mod_node_page_state(pgdat, >>> - folio_test_swapbacked(folio) ? >>> - NR_SHMEM_PMDMAPPED : NR_FILE_PMDMAPPED, >>> - -nr_pmdmapped); >>> - } >>> if (nr) { >>> - idx = folio_test_anon(folio) ? NR_ANON_MAPPED : NR_FILE_MAPPED; >>> - __lruvec_stat_mod_folio(folio, idx, -nr); >>> - >> >> >> We can now even do: >> >> diff --git a/mm/rmap.c b/mm/rmap.c >> index 9ed995da4709..7a147195e512 100644 >> --- a/mm/rmap.c >> +++ b/mm/rmap.c >> @@ -1555,18 +1555,17 @@ static __always_inline void __folio_remove_rmap(struct folio *folio, >> break; >> } >> >> - if (nr) { >> - /* >> - * Queue anon large folio for deferred split if at least one >> - * page of the folio is unmapped and at least one page >> - * is still mapped. >> - * >> - * Check partially_mapped first to ensure it is a large folio. >> - */ >> - if (folio_test_anon(folio) && partially_mapped && >> - list_empty(&folio->_deferred_list)) >> - deferred_split_folio(folio); >> - } >> + /* >> + * Queue anon large folio for deferred split if at least one >> + * page of the folio is unmapped and at least one page >> + * is still mapped. >> + * >> + * Check partially_mapped first to ensure it is a large folio. >> + */ >> + if (folio_test_anon(folio) && partially_mapped && >> + list_empty(&folio->_deferred_list)) >> + deferred_split_folio(folio); >> + > > Dumb question: why is it okay to remove the 'if (nr)' condition here? > It seems to me by looking at the code in case RMAP_LEVEL_PMD that it > is possible for partially_mapped to be true while nr == 0. Not a dumb question at all, and I cannot immediately tell if we might have to move the "nr" check to the RMAP_LEVEL_PMD case (I feel like we're good, but will have to double check). So let's keep it as is for now and I'll perform that change separately. Thanks! -- Cheers, David / dhildenb