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 20163377A82; Thu, 20 Aug 2026 18:04:25 +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=1787249067; cv=none; b=QAH92oDKeN9G48VzxsKA6jJ4qWHrSzVr648215B+Ep1rPD2ksf4R/dn/4tzIpmUO9i6HysvrowrRtTFeJaXmlJfIn2qaXP1QG6Ow4RAV5wmmqb30aVkdzKj5YJnP4CeupcxjI1xsTFj7JHjO99/OEbs3p7Q1xFUZeCieI9WZR1o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787249067; c=relaxed/simple; bh=KVdbAVTnk5hfvI5Vl7bEmwzD6WiBof/X+WjRvvyOBtU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=PHWO4cr/HzsLXNHf2jQG0tSUkgrZRoq/HZ43ZBRogmWD2PyTc3Tu7rgAAHOImZ68+3rM/DzDcz27g4Z24DX9U4YxHAmGo2WDk6h59WtN5tgSZ5RQ3cBLEViEvQ3g7tn9eMXKU2Bhm3GiEbk+zXjy3BGCb9DUQ2vsLsK0gWT7dSw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L8okw7BR; 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="L8okw7BR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C9621F000E9; Thu, 20 Aug 2026 18:04:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787249065; bh=m3qrj+DL9uEso2X6MTIsEHUQC1V8fM2Rlt+MQVnuAxw=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=L8okw7BR1E/5RimVg/1EDxrCZxuIBjTDfouneBnY5FzQATWpJvFBVnwvzrBp1tu4h P8dhL3kXkEp3fyut0ouByeDUHGK7mTOuCcr8RItl12hvAOKWuWVbfBMt6RYk7wyRPO Qe+vDRlhE1YURdow/DrxZ2r05BGdQaxq332JoDD9YrpQys4pvo2dQJ2cu6vpSIonb+ v5XU7S4iQP4xwamfAJgWRyWHTaFpWpQZ/cAE/2yjVQYSSH/8MxlHfPGj/cwRuChCPZ gsaRxLTlp7a526U0zazwcjSi2rQ2r+SsiC0dNr6pU+9WZ66RzV11HlCEcKodcUB3Cl r5jamZMCZm6Dg== Message-ID: Date: Thu, 20 Aug 2026 20:04:06 +0200 Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v5 05/10] mm/cma: Introduce cma_alloc_at() API To: Thierry Reding , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Jonathan Hunter , David Airlie , Simona Vetter , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Sowjanya Komatineni , Luca Ceresoli , Mikko Perttunen , Yury Norov , Rasmus Villemoes , Russell King , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , Sven Schnelle , Andrew Morton , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Marek Szyprowski , Robin Murphy , Sumit Semwal , Benjamin Gaignard , Brian Starkey , John Stultz , "T.J. Mercier" , =?UTF-8?Q?Christian_K=C3=B6nig?= , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Catalin Marinas , Will Deacon , Chun Ng Cc: Thierry Reding , devicetree@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux.dev, linaro-mm-sig@lists.linaro.org, linux-trace-kernel@vger.kernel.org, Thierry Reding References: <20260814-tegra-vpr-v5-0-71832b5d0246@nvidia.com> <20260814-tegra-vpr-v5-5-71832b5d0246@nvidia.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: <20260814-tegra-vpr-v5-5-71832b5d0246@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit > /* This part must be outside protection */> diff --git a/mm/cma.c b/mm/cma.c > index a10ea37a261d..1e1ebae79090 100644 > --- a/mm/cma.c > +++ b/mm/cma.c > @@ -936,6 +936,141 @@ struct page *cma_alloc_frozen_compound(struct cma *cma, unsigned int order) > return __cma_alloc_frozen(cma, 1 << order, order, gfp); > } > > +static int cma_range_alloc_at(struct cma *cma, struct cma_memrange *cmr, > + unsigned long offset, unsigned long count, > + struct page **pagep, gfp_t gfp) > +{ > + struct page *page = NULL; > + unsigned long pfn; > + int ret = -EBUSY; > + > + spin_lock_irq(&cma->lock); > + > + /* > + * If the request is larger than the available number of pages, stop > + * right away. > + */ > + if (count > cma->available_count) > + goto unlock; > + > + ret = bitmap_allocate(cmr->bitmap, offset, count); > + if (ret < 0) > + goto unlock; > + > + pfn = cmr->base_pfn + offset; > + page = pfn_to_page(pfn); > + > + /* > + * Do not hand out page ranges that are not contiguous, so > + * callers can just iterate the pages without having to worry > + * about these corner cases. > + */ > + if (!page_range_contiguous(page, count)) { > + pr_warn_ratelimited("%s: %s: skipping non-contiguous area [0x%lx-0x%lx]", > + __func__, cma->name, pfn, pfn + count - 1); > + ret = -EBUSY; > + goto clear; > + } > + > + cma->available_count -= count; > + > + /* > + * It's safe to drop the lock here. We've marked this region for > + * our exclusive use. If the migration fails we will take the > + * lock again and unmark it. > + */ > + spin_unlock_irq(&cma->lock); > + > + mutex_lock(&cma->alloc_mutex); > + ret = alloc_contig_frozen_range(pfn, pfn + count, ACR_FLAGS_CMA, gfp); > + mutex_unlock(&cma->alloc_mutex); > + There is quite some code duplication with cma_range_alloc(). Please try harder to factor common code out and reuse it. > + if (ret < 0) > + goto free; > + > + *pagep = page; > + > + return 0; > + > +free: > + /* we need to reacquire the lock to clean up the internal state */ > + spin_lock_irq(&cma->lock); > + cma->available_count += count; > +clear: > + bitmap_clear(cmr->bitmap, offset, count); > +unlock: > + spin_unlock_irq(&cma->lock); > + return ret; > +} > + > +static struct page *__cma_alloc_at_frozen(struct cma *cma, unsigned long offset, > + unsigned long count, gfp_t gfp) > +{ > + const char *name = cma ? cma->name : NULL; > + struct page *page = NULL; > + int ret = -ENOMEM, r; > + unsigned long i; > + > + if (!cma || !cma->count) > + return page; > + > + pr_debug("%s(cma %p, name: %s, offset %lu, count %lu)\n", __func__, > + (void *)cma, cma->name, offset, count); > + > + if (!count) > + return page; > + > + trace_cma_alloc_at_start(name, offset, count, cma->available_count, > + cma->count); > + > + for (r = 0; r < cma->nranges; r++) { > + page = NULL; > + > + ret = cma_range_alloc_at(cma, &cma->ranges[r], offset, count, > + &page, gfp); > + if (ret != -EBUSY || page) > + break; > + } > + > + /* > + * CMA can allocate multiple page blocks, which results in different > + * blocks being marked with different tags. Reset the tags to ignore > + * those page blocks. > + */ > + if (page) { > + for (i = 0; i < count; i++) > + page_kasan_tag_reset(page + i); > + } > + > + if (ret && !(gfp & __GFP_NOWARN)) { > + pr_err_ratelimited("%s: %s: alloc failed, request: %lu, %lu pages, ret: %d\n", > + __func__, cma->name, offset, count, ret); > + cma_debug_show_areas(cma); > + } > + > + pr_debug("%s(): returned %p\n", __func__, page); > + trace_cma_alloc_at_finish(name, page ? page_to_pfn(page) : 0, page, > + count, ret); > + > + if (page) { > + count_vm_event(CMA_ALLOC_SUCCESS); > + cma_sysfs_account_success_pages(cma, count); > + } else { > + count_vm_event(CMA_ALLOC_FAIL); > + cma_sysfs_account_fail_pages(cma, count); > + } Also here, way too much code duplication with __cma_alloc_frozen(). There must be a better way :) (I really prefer this direction of the patch set) -- Cheers, David