From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 D174828151F for ; Tue, 6 May 2025 14:36:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746542194; cv=none; b=s0d75hvI7Tv0UYWjENcQBEtiQXAlZ+8ChVQI+iqLB3SRsNR4BWlCUbnUCmrCYW2k+dOJDPSxsbpOylt1J4Y9kokCf7mpOodiN8oPc8X6JNjWMJfFua6hLiEbuLxlOU+e/Eb4Ee+jk8U2EnWZxmNvkU0gvPVHU8uv6QSNf/MhZq4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746542194; c=relaxed/simple; bh=pLR8SzIXEvIb7U/GF5VXmYNQ43ylNgBaVEB/MFrcW0o=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Sj4qKCi9jh1omVBslS+Y0GcGCm8hHOO9b/5/5JxzRejfvbcIRDbqbKjHU6EMhTN0co7i6QMxrO1oCZld5Tyh40gyFHW8Hzhmd1byXak10mH2i8xwQmeqfQlMyXUY6F68cA4HIPDg3XEBZMO6wRa5MiGeMBXj83VdL3wwzzDBrFY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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=gSENK6OJ; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine 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="gSENK6OJ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1746542191; 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=IzH/tkJn6lVBdTS8VMGJ+rH7vzL7J2XnCGspuIlgQmc=; b=gSENK6OJWIlEdNJIpEgGEjkcuERAndYLSfVWgyEyYqGzFLF1aJNk2FWdKQ2czPWsmsKvp6 FJDJs2FzPshD6SfbFolxZHEriEeTsa/6TrW6Lf8wkEWQ5DqYI0JMTj4q/RSjbr6kcT6fOz GHk8qyzi9EHsO6ZXaoMkmWe8vtm1TBE= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-163-con3JFQ6PxqcPa9n_gzXSA-1; Tue, 06 May 2025 10:36:30 -0400 X-MC-Unique: con3JFQ6PxqcPa9n_gzXSA-1 X-Mimecast-MFC-AGG-ID: con3JFQ6PxqcPa9n_gzXSA_1746542186 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-43f405810b4so29887325e9.1 for ; Tue, 06 May 2025 07:36:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1746542186; x=1747146986; 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=IzH/tkJn6lVBdTS8VMGJ+rH7vzL7J2XnCGspuIlgQmc=; b=Ay+u142Z6D9gpk3ZrZRRgwO/kLK4ZkpBvwZCXsQj1ROCJO2M9FI8lgU4yRjNIxMdTz 0wjZMWv7bZcfi4coy6f46XMU4a5qLSw0gjqDn8BGcROWBnCGiqQWvWKcM3kWeeLjQnvW gfHaHeXZfd17n21eu8Voeex1eRvYZw6fsrEVwjSBsjvqpFLJMisYbVpEhCiUcTviKxwC Tk7mklMG2zIoImih+O/5hrg+4Pf5pyLgIiMb1Sjj9pM1iIkE7Zf9rZuNP45iXYSYB6cN WP06xAXwEHZprVX2Gmd1+m9o1JulxW7qS5JWYrxn4i9FpMPheFJzAPOA15fHi717ROy+ pIhA== X-Forwarded-Encrypted: i=1; AJvYcCU3jdP9hwihmjdpRXAf2C8IR+XK7lSdiSuZPp7UX1m4zkAFfBk8FHyYcc1U7YMNibvx2wsPQkwcDmwhEdg=@vger.kernel.org X-Gm-Message-State: AOJu0YzuyQjS3q21E/QissKAK0qVLtwbuYdJs0Y/KQLkURuIpO2r7Afb wdVSkWpjkjEwNHPHYTB4k9mxBCqicM4iit5Twu7KDCVyKa9XV5KQsk38ttlNzAk+hqRRoer6mZb H2cXLOc732Z8ac1CxKfxaJBoLXtR0Gb9s3NSNfwY0sGoukkrgjG2VKwLQIARM5A== X-Gm-Gg: ASbGncu5KYBsCAhzbAYtI2sWFRhfTEKmu8hY4x39MBG+Ef7gMDBLnRBOzVGdQwze7wg cC038GHF1nRWT3ze0N1x20d+PXrLS4r9hADaRPtD8wdG6XzlscnHOIfdljo3Im8Y7kPxUdz0d59 t1RdiWhBhfedaj35IzdFlMfVPTLrX0lwreSzOjQmHH+PNWnHSMkUGGfmgw7teHpPbph9Ot6ghRY c8L8iJ6TB4tk3soUj/bAi+EJMBPNk+K8jG79vRc1BuPly/3sm1MHjc3TlSZRGe1LMNAaVpdEi2N ainc1voPXtd0AQpwAPe5m5NcDiDFThax/w2eDRCoNzIyx61xeIs= X-Received: by 2002:a05:600c:a409:b0:43b:cd0d:9466 with SMTP id 5b1f17b1804b1-441d0a909b9mr32408685e9.9.1746542186125; Tue, 06 May 2025 07:36:26 -0700 (PDT) X-Google-Smtp-Source: AGHT+IFELAacPpWBYwZLLNgreFFAeKxOJOPVs/9qbII4n9nSgPnrvi/TERouc+DLkXPGSqiv0SFhDw== X-Received: by 2002:a05:600c:a409:b0:43b:cd0d:9466 with SMTP id 5b1f17b1804b1-441d0a909b9mr32408275e9.9.1746542185689; Tue, 06 May 2025 07:36:25 -0700 (PDT) Received: from ?IPV6:2a01:599:915:8911:b13f:d972:e237:7fe2? ([2a01:599:915:8911:b13f:d972:e237:7fe2]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-441b8a285c2sm171119875e9.32.2025.05.06.07.36.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 06 May 2025 07:36:25 -0700 (PDT) Message-ID: Date: Tue, 6 May 2025 16:36:23 +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: [REGRESSION] Re: [PATCH v3 3/6] mm: shmem: add large folio support for tmpfs To: Baolin Wang , Daniel Gomez Cc: =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= , akpm@linux-foundation.org, hughd@google.com, willy@infradead.org, wangkefeng.wang@huawei.com, 21cnbao@gmail.com, ryan.roberts@arm.com, ioworker0@gmail.com, da.gomez@samsung.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, regressions@lists.linux.dev, intel-gfx@lists.freedesktop.org, Eero Tamminen References: <035bf55fbdebeff65f5cb2cdb9907b7d632c3228.1732779148.git.baolin.wang@linux.alibaba.com> <57dc4929-268b-4f3f-a0f8-43d6ec85974f@linux.alibaba.com> <72978e3a-ee67-47d4-b06d-e911bc5d57ff@redhat.com> 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: 8bit On 06.05.25 05:33, Baolin Wang wrote: > > > On 2025/5/2 23:31, David Hildenbrand wrote: >> On 02.05.25 15:10, Daniel Gomez wrote: >>> On Fri, May 02, 2025 at 09:18:41AM +0100, David Hildenbrand wrote: >>>> On 02.05.25 03:02, Baolin Wang wrote: >>>>> >>>>> >>>>> On 2025/4/30 21:24, Daniel Gomez wrote: >>>>>> On Wed, Apr 30, 2025 at 02:20:02PM +0100, Ville Syrjälä wrote: >>>>>>> On Wed, Apr 30, 2025 at 02:32:39PM +0800, Baolin Wang wrote: >>>>>>>> On 2025/4/30 01:44, Ville Syrjälä wrote: >>>>>>>>> On Thu, Nov 28, 2024 at 03:40:41PM +0800, Baolin Wang wrote: >>>>>>>>> Hi, >>>>>>>>> >>>>>>>>> This causes a huge regression in Intel iGPU texturing performance. >>>>>>>> >>>>>>>> Unfortunately, I don't have such platform to test it. >>>>>>>> >>>>>>>>> >>>>>>>>> I haven't had time to look at this in detail, but presumably the >>>>>>>>> problem is that we're no longer getting huge pages from our >>>>>>>>> private tmpfs mount (done in i915_gemfs_init()). >>>>>>>> >>>>>>>> IIUC, the i915 driver still limits the maximum write size to >>>>>>>> PAGE_SIZE >>>>>>>> in the shmem_pwrite(), >>>>>>> >>>>>>> pwrite is just one random way to write to objects, and probably >>>>>>> not something that's even used by current Mesa. >>>>>>> >>>>>>>> which prevents tmpfs from allocating large >>>>>>>> folios. As mentioned in the comments below, tmpfs like other file >>>>>>>> systems that support large folios, will allow getting a highest >>>>>>>> order >>>>>>>> hint based on the size of the write and fallocate paths, and then >>>>>>>> will >>>>>>>> attempt each allowable huge order. >>>>>>>> >>>>>>>> Therefore, I think the shmem_pwrite() function should be changed to >>>>>>>> remove the limitation that the write size cannot exceed PAGE_SIZE. >>>>>> >>>>>> To enable mTHP on tmpfs, the necessary knobs must first be enabled >>>>>> in sysfs >>>>>> as they are not enabled by default IIRC (only THP, PMD level). >>>>>> Ville, I >>>>>> see i915_gemfs the huge=within_size mount option is passed. Can you >>>>>> confirm >>>>>> if /sys/kernel/mm/transparent_hugepage/hugepages-*/enabled are also >>>>>> marked as >>>>>> 'always' when the regression is found? >>>>> >>>>> The tmpfs mount will not be controlled by >>>>> '/sys/kernel/mm/transparent_hugepage/hugepages-*Kb/enabled' (except for >>>>> the debugging options 'deny' and 'force'). >>>> >>>> Right, IIRC as requested by Willy, it should behave like other FSes >>>> where >>>> there is no control over the folio size to be used. >>> >>> Thanks for reminding me. I forgot we finally changed it. >>> >>> Could the performance drop be due to the driver no longer using >>> PMD-level pages? >> >> I suspect that the faulting logic will now go to a smaller order first, >> indeed. >> >> ... trying to digest shmem_allowable_huge_orders() and >> shmem_huge_global_enabled(), having a hard time trying to isolate the >> tmpfs case: especially, if we run here into the vma vs. !vma case. >> >> Without a VMA, I think we should have "mpfs will allow getting a highest >> order hint based on and fallocate paths, then will try each allowable >> order". >> >> With a VMA (no access hint), "we still use PMD-sized order to locate >> huge pages due to lack of a write size hint." >> >> So if we get a fallocate()/write() that is, say, 1 MiB, we'd now >> allocate an 1 MiB folio instead of a 2 MiB one. > > Right. > > So I asked Ville how the shmem folios are allocated in the i915 driver, > and to see if we can make some improvements. Maybe preallocation (using fallocate) might be reasonable for their use case: if they know they will consume all that memory either way. If it's sparse, it's more problematic. -- Cheers, David / dhildenb