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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DAD53D35170 for ; Wed, 1 Apr 2026 10:19:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 44C526B0098; Wed, 1 Apr 2026 06:19:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 4241B6B0099; Wed, 1 Apr 2026 06:19:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3397A6B009B; Wed, 1 Apr 2026 06:19:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 1FD966B0098 for ; Wed, 1 Apr 2026 06:19:22 -0400 (EDT) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id C5A975A822 for ; Wed, 1 Apr 2026 10:19:21 +0000 (UTC) X-FDA: 84609589722.28.BC31E2F Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf30.hostedemail.com (Postfix) with ESMTP id 018A78000B for ; Wed, 1 Apr 2026 10:19:19 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=mgp5cEJV; spf=pass (imf30.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1775038760; a=rsa-sha256; cv=none; b=urZqHiNe6MUoJ1sjt2zxF8y4GABcz3SOvu+FvDcFCBrWj6Ssuwm8a+LOs992tv5a5eZSns 4D1q/UQHGEz6l1YT8sglNupIJbh/ue6B0qcOupipMu2iaDJaSc+iSzcsIE3rG8BElmfabI ckGcAKdx83z2pPWhTl8MfzkQw3bBYYs= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1775038760; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to: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=L/FzrensQpIwhFFDEBYZvI0Pt+Ob7XKc1YVc3lbfLCA=; b=SEbdzmvukbpcX+SKJtbTUmjY6Cj/RrI9OO+4KS0ySSwpAujd76f4kwWhDJHrrTxKZBnx9r PVt/wU43Uro80yd4t4wnWO2Kfb6sN/IHiyIrk4gUSsoUk0ePzqJ2cLhsOgF0hlQxZgF2PR 1muUyLpxAVH08S5pwYntbtkVF7VDT84= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=mgp5cEJV; spf=pass (imf30.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 53D9E6012A; Wed, 1 Apr 2026 10:19:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 61327C2BCB0; Wed, 1 Apr 2026 10:19:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775038759; bh=NWaWxPFYGt4QvWWCFBv3cLx1QXtfQJgttn7A5FsNLh0=; h=Date:Subject:To:References:From:In-Reply-To:From; b=mgp5cEJV6xB8gsye4gAENpIx1iElgAYjiSyfrr1MX3fgoAwcKN/WARjps/5rzXsZG QjdI/vAyQ48idT54+9s9p4d+cMQ1+95gI1iThWeTu9mqGcNEGCD9wfei8AMla83eGt b1gWesOKcEw7CK2rLexC0I6odvWKBwRkr575jXJWU9wde9/RMNzeu/Ows/NfKmJPh+ 7q/w8ip4U2ZCNN0vOjXBn5HE8iPrsP0nf/TimFGM3mk34ak0XlwzCpHC4WA9jpq5Ko 2kTuimuhmu67gp3OGZDFetRSDfkpApKjpLz/YpMeToJINOpaHUFeBNYgWU6lWUsFfg hFge6PjUHLFbg== Message-ID: <7ace33f9-419c-4a25-906a-d78545d02a3a@kernel.org> Date: Wed, 1 Apr 2026 12:19:11 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 2/3] vmalloc: Optimize vfree with free_pages_bulk() To: Muhammad Usama Anjum , Andrew Morton , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Uladzislau Rezki , Nick Terrell , David Sterba , Vishal Moola , linux-mm@kvack.org, linux-kernel@vger.kernel.org, bpf@vger.kernel.org, Ryan.Roberts@arm.com, david.hildenbrand@arm.com References: <20260401101634.2868165-1-usama.anjum@arm.com> <20260401101634.2868165-3-usama.anjum@arm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260401101634.2868165-3-usama.anjum@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 018A78000B X-Stat-Signature: 1cxby1b77m6u8xfwi3fwksrqh3jg9p75 X-HE-Tag: 1775038759-930632 X-HE-Meta: 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 L/DkAdBY dSqK7XLDkzOfSKY+emNLFJCzKU0hkY/qwPCBQHmlW4nP3BS7zcAvagLNDrcVJvbE/sn5yO4fJljAqRiiY/Wka3zgsyk6feBSvYXYiusUVMF9SNSHE6+urSoaysysGF/qH5kNAV2ZMlbgxDOA+LDGDJYcVpoz8T+dZtBVDv0oYrmyKEfydZB7n640e2T6nO3IWWtuK5Z9h03Kaxthtj7WDHYJXekUvvXpBX1Q7J4EQm6mEJPC5umeGRyQsqiOs2I+W9OmZUGD4UpruqZVCpYFUrGnShpgLGuchH4QYpZiJqg8RT4WvKN2LhkNhyCoqYbyRvTvbcW2PZ1nU8aIP6HDaB/P1k5d3Q/A1umpO2+NYPlvChMAGIEXISPmoaLdJb58nu7JcHYKlK/oE5M4D4MsqK/WOmhkN8ON/vfhgo+yqJN+C1k3nrzdYmTBYAvcGZ0WOaf0J Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/1/26 12:16, Muhammad Usama Anjum wrote: > From: Ryan Roberts > > Whenever vmalloc allocates high order pages (e.g. for a huge mapping) it > must immediately split_page() to order-0 so that it remains compatible > with users that want to access the underlying struct page. > Commit a06157804399 ("mm/vmalloc: request large order pages from buddy > allocator") recently made it much more likely for vmalloc to allocate > high order pages which are subsequently split to order-0. > > Unfortunately this had the side effect of causing performance > regressions for tight vmalloc/vfree loops (e.g. test_vmalloc.ko > benchmarks). See Closes: tag. This happens because the high order pages > must be gotten from the buddy but then because they are split to > order-0, when they are freed they are freed to the order-0 pcp. > Previously allocation was for order-0 pages so they were recycled from > the pcp. > > It would be preferable if when vmalloc allocates an (e.g.) order-3 page > that it also frees that order-3 page to the order-3 pcp, then the > regression could be removed. > > So let's do exactly that; update stats separately first as coalescing is > hard to do correctly without complexity. Use free_pages_bulk() which uses > the new __free_contig_range() API to batch-free contiguous ranges of pfns. > This not only removes the regression, but significantly improves > performance of vfree beyond the baseline. > > A selection of test_vmalloc benchmarks running on arm64 server class > system. mm-new is the baseline. Commit a06157804399 ("mm/vmalloc: request > large order pages from buddy allocator") was added in v6.19-rc1 where we > see regressions. Then with this change performance is much better. (>0 > is faster, <0 is slower, (R)/(I) = statistically significant > Regression/Improvement): > > +-----------------+----------------------------------------------------------+-------------------+--------------------+ > | Benchmark | Result Class | mm-new | this series | > +=================+==========================================================+===================+====================+ > | micromm/vmalloc | fix_align_alloc_test: p:1, h:0, l:500000 (usec) | 1331843.33 | (I) 67.17% | > | | fix_size_alloc_test: p:1, h:0, l:500000 (usec) | 415907.33 | -5.14% | > | | fix_size_alloc_test: p:4, h:0, l:500000 (usec) | 755448.00 | (I) 53.55% | > | | fix_size_alloc_test: p:16, h:0, l:500000 (usec) | 1591331.33 | (I) 57.26% | > | | fix_size_alloc_test: p:16, h:1, l:500000 (usec) | 1594345.67 | (I) 68.46% | > | | fix_size_alloc_test: p:64, h:0, l:100000 (usec) | 1071826.00 | (I) 79.27% | > | | fix_size_alloc_test: p:64, h:1, l:100000 (usec) | 1018385.00 | (I) 84.17% | > | | fix_size_alloc_test: p:256, h:0, l:100000 (usec) | 3970899.67 | (I) 77.01% | > | | fix_size_alloc_test: p:256, h:1, l:100000 (usec) | 3821788.67 | (I) 89.44% | > | | fix_size_alloc_test: p:512, h:0, l:100000 (usec) | 7795968.00 | (I) 82.67% | > | | fix_size_alloc_test: p:512, h:1, l:100000 (usec) | 6530169.67 | (I) 118.09% | > | | full_fit_alloc_test: p:1, h:0, l:500000 (usec) | 626808.33 | -0.98% | > | | kvfree_rcu_1_arg_vmalloc_test: p:1, h:0, l:500000 (usec) | 532145.67 | -1.68% | > | | kvfree_rcu_2_arg_vmalloc_test: p:1, h:0, l:500000 (usec) | 537032.67 | -0.96% | > | | long_busy_list_alloc_test: p:1, h:0, l:500000 (usec) | 8805069.00 | (I) 74.58% | > | | pcpu_alloc_test: p:1, h:0, l:500000 (usec) | 500824.67 | 4.35% | > | | random_size_align_alloc_test: p:1, h:0, l:500000 (usec) | 1637554.67 | (I) 76.99% | > | | random_size_alloc_test: p:1, h:0, l:500000 (usec) | 4556288.67 | (I) 72.23% | > | | vm_map_ram_test: p:1, h:0, l:500000 (usec) | 107371.00 | -0.70% | > +-----------------+----------------------------------------------------------+-------------------+--------------------+ > > Fixes: a06157804399 ("mm/vmalloc: request large order pages from buddy allocator") > Closes: https://lore.kernel.org/all/66919a28-bc81-49c9-b68f-dd7c73395a0d@arm.com/ > Acked-by: Vlastimil Babka (SUSE) > Acked-by: Zi Yan > Signed-off-by: Ryan Roberts > Co-developed-by: Muhammad Usama Anjum > Signed-off-by: Muhammad Usama Anjum Acked-by: David Hildenbrand (Arm) -- Cheers, David