From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 43486C125 for ; Mon, 19 Aug 2024 08:36:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724056598; cv=none; b=lFYniLhhWYgUTPavkkrOQNev2gSGyYCiz9jhoQFbDuLsD++Yq912BCQQK6ehc+H5GijEyD4Lbt47eup02yjLlDuTOnpTfi+CRyYUwtqpok7UcyQbxocLO9OLyYJtl65zW/GSE+KUFzrDx8/5sM6g0l3Omt8ouFI1KWLqNaSsXFI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1724056598; c=relaxed/simple; bh=nNLE4eoqbuu9Ak+gKu7Z23nQWMAS5HDz3UUfx5oAZ44=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Jc22bLFTt/+c1mzIV+NGFMj62ELYEvu6s76mv3+iYH32sjKcL55Y9lQEm+4y95LIknQoHJz5AyGm0UHtj/L0uNPou1oJgOSQ1O6iSAqsd7+TcJ0AmCXPG967becVOfjyqka80sDcUpssKXMYRm1HbfjAv3NrDJ/ZBwByjd2zzgU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=PYYScp1+; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="PYYScp1+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1724056595; 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=ISqrIQKsaqEr77ln38QuXukk21qsyi8yzuO8Lde5KzM=; b=PYYScp1+g6aSeaq1JrHMM/Dvqz7xk3QFMTAbSBBzIY980Gli+sM4Nryoz1gJ8B3QnKL1Ug I1oL7pM8ii1HGIAjOfBghYsAE3ZTmy6w/7pYGQhk9BL4Yog70E/E6WDzXFMhEPZZq0vcqO vYXZf6s0cDmYPMBVyO+wisPHfUog4qQ= Received: from mail-ej1-f70.google.com (mail-ej1-f70.google.com [209.85.218.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-610-E_wQ55W9O86TycF8VFdcxA-1; Mon, 19 Aug 2024 04:36:34 -0400 X-MC-Unique: E_wQ55W9O86TycF8VFdcxA-1 Received: by mail-ej1-f70.google.com with SMTP id a640c23a62f3a-a7ab644746eso274439066b.1 for ; Mon, 19 Aug 2024 01:36:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1724056593; x=1724661393; 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=ISqrIQKsaqEr77ln38QuXukk21qsyi8yzuO8Lde5KzM=; b=i5WpcY5PlDzwb+TwIOip5Pjp1nmKLueY08SliVJ6bkrU39zUZQrZWntRGCYOIUUUR+ bjxThEeyjRO/amOlmu0AvOMD2Hn6yuGNgV5nq1c2i1hrkfXO8UhZ11iiAAu9EuZaeAb0 lgKIJZhVRjAGEORYxqA69+j1Sl0sFh+ZXcI6JkLPcjJZ2ddnozHs/3FPVwdLIB9nlKrh j0aBNEgZ/ESxozbEjjCP96tqbMNNFQ2dYNcuYbQ/mGVYGiYFa46Zfb49dYLSRacLrkb6 pzXzQZcI7HG8cv2uXdE9zXCOzazjiY1lR2tDqQxsD/JZMLEvBuxyvtpGNM1J1frMFeKg M4Ew== X-Forwarded-Encrypted: i=1; AJvYcCULQfkYIhAbwgoO9AeGMO60b+u7vEotXzTmTSYEqPfjiaKSJyy7RHvq/VayAwWfssBAeynU0yvajwJIxtHTXmQsaciv+jzx/rK98nT3 X-Gm-Message-State: AOJu0YyYukRgA8z58jQkQXsvE+oQcRKjGdQKLeZ6c0B/kHKHlOXaenYx f9zAEgmMXFY2/DRkYjGXpVfJpEKucYnnuT/cu2UnyPpq810I2FxrBWoGOaVHq/fYTb6489sSS9/ WFt5wW93LGbRdGtd74zeCFQ+Sz5cKf6tkZv+i6ei7moOWp1M/0O0dTpvPfVs7pg== X-Received: by 2002:a17:907:c7e7:b0:a77:e48d:bc8 with SMTP id a640c23a62f3a-a839292f10fmr720130866b.21.1724056592881; Mon, 19 Aug 2024 01:36:32 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGWwcbxCxz3Zy38oz3eeNgITHsbVen71EQ/nghFVSqxobixhgS9j5bCtaQkIIaQFRosa15X0A== X-Received: by 2002:a17:907:c7e7:b0:a77:e48d:bc8 with SMTP id a640c23a62f3a-a839292f10fmr720129266b.21.1724056592343; Mon, 19 Aug 2024 01:36:32 -0700 (PDT) Received: from [100.81.188.195] (ipb218f908.dynamic.kabel-deutschland.de. [178.24.249.8]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-a838396d304sm602821266b.212.2024.08.19.01.36.31 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 19 Aug 2024 01:36:31 -0700 (PDT) Message-ID: Date: Mon, 19 Aug 2024 10:36:30 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/5] mm: khugepaged: expand the is_refcount_suitable() to support file folios To: Baolin Wang , akpm@linux-foundation.org Cc: hughd@google.com, willy@infradead.org, 21cnbao@gmail.com, ryan.roberts@arm.com, shy828301@gmail.com, ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: From: David Hildenbrand Content-Language: en-US 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: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 19.08.24 10:14, Baolin Wang wrote: > Expand the is_refcount_suitable() to support reference checks for file folios, > as preparation for supporting shmem mTHP collapse. > > Signed-off-by: Baolin Wang > --- > mm/khugepaged.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index cdd1d8655a76..f11b4f172e61 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -549,8 +549,14 @@ static bool is_refcount_suitable(struct folio *folio) > int expected_refcount; > > expected_refcount = folio_mapcount(folio); > - if (folio_test_swapcache(folio)) > + if (folio_test_anon(folio)) { > + expected_refcount += folio_test_swapcache(folio) ? > + folio_nr_pages(folio) : 0; > + } else { > expected_refcount += folio_nr_pages(folio); > + if (folio_test_private(folio)) > + expected_refcount++; > + } Alternatively, a bit neater if (!folio_test_anon(folio) || folio_test_swapcache(folio)) expected_refcount += folio_nr_pages(folio); if (folio_test_private(folio)) expected_refcount++; The latter check should be fine even for anon folios (although always false) > > return folio_ref_count(folio) == expected_refcount; > } > @@ -2285,8 +2291,7 @@ static int hpage_collapse_scan_file(struct mm_struct *mm, unsigned long addr, > break; > } > > - if (folio_ref_count(folio) != > - 1 + folio_mapcount(folio) + folio_test_private(folio)) { The "1" is due to the pagecache, right? IIUC, we don't hold a raised folio refcount as we do the xas_for_each(). -- Cheers, David / dhildenb