From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 1943452ED2E; Tue, 8 Sep 2026 11:48:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788868142; cv=none; b=U8w+sAzmJdRZkgHi6FiI9GLV468T1vo0kEuZhundW+mcyQ69vSSR++m8kVskaYUHjEwtAGJ9qvNYMF8rVHachzHfJCnwJeIla8wgxbXM4KiFzWzHtBoZo6x6NZwUYraLZrlLHGYGlcoAOquug1qxObOzvuT8J8XwweTFrDE6gLk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788868142; c=relaxed/simple; bh=oXbRvgHV07Ifi460LsAH8jEnEwsMepZEmgvxkvfRAHo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jAxsNUwXSQZHG4YI7oPFFQlFUePg3InZlsv6vUYfSIiCSDDrM1kmOv9HvD97twI2OmFVTIMFlxIa89XGENrLMpAspevSHGuF4iQhfjJYDh8TMk7bjW6e6a7CI8rpJ/3eJR6mUBVcASbDWmer9qR/UGgw7Iacmv1v+G5KmL+Ubyk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D4yNB+iH; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="D4yNB+iH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7C5B91F00A3D; Tue, 8 Sep 2026 11:48:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788868130; bh=E3fsDMUp6iZPwqWolrjkrZvy70fQS6FinWdQXIMSMow=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=D4yNB+iHgYWM2xH5dEAI8mPSRYWnnNFm5P6il2ewjQLawqqHvZ0iRVtiPpend37Ov BVgRiJpLfeZphjBvLOtdJquXE28iPZ5jAq9L3m73yktY98VNQiyduG1fGDmCvwVCFb OvLVA5AbLLz20lLr4HCl1/Zo5X94Rj/pLMSJKZwrZUn0ZKKRR25TKJf8kMmj58VhYa 5EFv/GYUk2Cp8uy7bb9mBwcWZI3nmjTc/K2o4v2pW1t25PbkazcJ2hQMXvqOr6CMwB BUgOfOJLNEmKpyPmA+NEmQzK8n1wSEEyA1X9FSj7HVQHwoVA4qOIzR04Pl5WRk30g8 HA2wuKBfwd1Vg== Message-ID: Date: Tue, 8 Sep 2026 13:48:36 +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 v3 4/6] mm/vmalloc: make set_area_direct_map HUGE_VMAP friendly To: Mike Rapoport Cc: Andrew Morton , =?UTF-8?Q?Adrian_Barna=C5=9B?= , Albert Ou , Alexander Gordeev , Alexandre Ghiti , Andy Lutomirski , Borislav Petkov , Brendan Jackman , Catalin Marinas , Christian Borntraeger , Dave Hansen , Gerald Schaefer , Heiko Carstens , Huacai Chen , Ingo Molnar , Len Brown , Palmer Dabbelt , Paul Walmsley , Pavel Machek , Peter Zijlstra , "H. Peter Anvin" , "Rafael J. Wysocki" , Ryan Roberts , Sven Schnelle , Thomas Gleixner , Uladzislau Rezki , Vasily Gorbik , WANG Xuerui , Will Deacon , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-pm@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, loongarch@lists.linux.dev References: <20260903-execmem-set-vm-perms-v0-2-v3-0-949b64a9f755@kernel.org> <20260903-execmem-set-vm-perms-v0-2-v3-4-949b64a9f755@kernel.org> <2b0f5877-e71a-4824-adeb-5af2dd8b0269@kernel.org> 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: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/8/26 13:12, Mike Rapoport wrote: > On Tue, Sep 08, 2026 at 12:41:48PM +0200, David Hildenbrand (Arm) wrote: >> On 9/3/26 11:28, Mike Rapoport (Microsoft) wrote: >>> set_area_direct_map() always updates direct map alias permissions in >>> single page increments. >>> >>> For HUGE_VMAP areas it's suboptimal. Not only the loop in >>> set_area_direct_map() needlessly has more iterations (e.g times 512 on >>> x86), but it also causes fragmentation of the direct map that could be >>> avoided for the HUGE_VMAP areas populated with large pages. >>> >>> All pages in an area are always of the same order: either same-order >>> large pages when VM_ALLOW_HUGE_VMAP is set and all huge pages were >>> successfully allocated, or order-0 page when VM_ALLOW_HUGE_VMAP is >>> cleared or when huge pages allocation fails and fallback path is taken. >>> >>> Instead of updating the direct map permissions for every order-0 page in >>> an area, use the area's page_order as the loop increment and update the >>> large pages in one call to set_direct_map_{invalid,default}_noflush(). >>> >>> Signed-off-by: Mike Rapoport (Microsoft) >>> --- >>> mm/vmalloc.c | 13 ++++++++----- >>> 1 file changed, 8 insertions(+), 5 deletions(-) >>> >>> diff --git a/mm/vmalloc.c b/mm/vmalloc.c >>> index 5506b180f5c27..6ed6c160abed7 100644 >>> --- a/mm/vmalloc.c >>> +++ b/mm/vmalloc.c >>> @@ -3367,12 +3367,15 @@ static inline void set_area_direct_map(const struct vm_struct *area, >>> int (*set_direct_map)(struct page *page, >>> unsigned int nr)) >>> { >>> - unsigned long i; >>> + unsigned int nr = (1U << vm_area_page_order(area)); >>> + >>> + for (unsigned long i = 0; i < area->nr_pages; i += nr) { >>> + if (page_address(area->pages[i])) { >>> + int err = set_direct_map(area->pages[i], nr); >> >> Do we really expect some pages to have a directmap and others not? > > Every page in the area can be allocated separately and > __vmalloc_area_node() has > > if (!(gfp_mask & (GFP_DMA | GFP_DMA32))) > gfp_mask |= __GFP_HIGHMEM; > > so generally speaking yes :) Ah, I was thinking in terms of HUGE_VMAP, because there we sure would expect all-or-nothing, right? -- Cheers, David