From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2499E2C15BB for ; Wed, 22 Apr 2026 18:50:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776883808; cv=none; b=k7d8jnYz072gky/sqBDIewNFBTjneAwobArB0ua+qPZJDB+fJvRQ+ced5UKipBHFAzVXZEwWvQE1YIfUCp0/AEuIDtrJTCP194UUYqhDYjNYFi7sdK2FbBdMQIUR0VOAAevcFz1bYYKrYWdISVKAPT2FqSHwP6eNbcjc7B42LpY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776883808; c=relaxed/simple; bh=PRcbGxXVn+TWgBm3sJFNt59RhR0CP0MQw5XEPliYcQo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=MUiHgoofhJoNCtot5Io33W+7dsBWJjKtsFEVxERBtITV65Clk/5tTd3BGVmuwX89Zzizw18aqFTj6rJEQqwgPI4AhNPn4Lnn/HPsr+rZ92IxhTAxbl2wHdvf5UG+mNRve6J9G+YOIhJUMzso+6+OfyCXhCaL87AWfV6S3rJv4LM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jAIEDdzG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="jAIEDdzG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 699E5C19425; Wed, 22 Apr 2026 18:50:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776883807; bh=PRcbGxXVn+TWgBm3sJFNt59RhR0CP0MQw5XEPliYcQo=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=jAIEDdzGdEaHrvn5Xd7STmKTqm2T2XldfKWf5vr0ekqMtSHo7neA4GPJOpSpAKReh AVfcLMYPCX3nOo0zR5EXdg1pzyLrIWBnabYXWq3JWmbjCENqcfEYf7r8a4aV6Tm08D NvDc/HPGXvpY71v1PFiDinN5YTj5l3MecrA6ECCgNmUv4Buj/v/1G4laqTeiuhP59B WXUgLoMux/zvVz+cg+87dFOgivzib+43+gFcQ6NsGZrZqccbs6i4nZn85v1GrCA8em Jg9oUKp+p6iv7RIYmUK3oP6XvMH4Bk/5ijGblcim242hF1pOGxXPlMUqmbUMMqA6vV Heg5sYvMCi5Hg== Message-ID: Date: Wed, 22 Apr 2026 20:50:00 +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 v4 2/5] mm/sparse-vmemmap: Pass @pgmap argument to memory deactivation paths To: Muchun Song , Andrew Morton , Muchun Song , Oscar Salvador , Michael Ellerman , Madhavan Srinivasan Cc: Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Nicholas Piggin , Christophe Leroy , aneesh.kumar@linux.ibm.com, joao.m.martins@oracle.com, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <20260422081420.4009847-1-songmuchun@bytedance.com> <20260422081420.4009847-3-songmuchun@bytedance.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: <20260422081420.4009847-3-songmuchun@bytedance.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/22/26 10:14, Muchun Song wrote: > Currently, the memory hot-remove call chain -- arch_remove_memory(), > __remove_pages(), sparse_remove_section() and section_deactivate() -- > does not carry the struct dev_pagemap pointer. This prevents the lower > levels from knowing whether the section was originally populated with > vmemmap optimizations (e.g., DAX with vmemmap optimization enabled). > > Without this information, we cannot call vmemmap_can_optimize() to > determine if the vmemmap pages were optimized. As a result, the vmemmap > page accounting during teardown will mistakenly assume a non-optimized > allocation, leading to incorrect memmap statistics. > > To lay the groundwork for fixing the vmemmap page accounting, we need > to pass the @pgmap pointer down to the deactivation location. Plumb the > @pgmap argument through the APIs of arch_remove_memory(), __remove_pages() > and sparse_remove_section(), mirroring the corresponding *_activate() > paths. > > Signed-off-by: Muchun Song > Acked-by: Mike Rapoport (Microsoft) > Reviewed-by: Oscar Salvador [...] > static void depopulate_section_memmap(unsigned long pfn, unsigned long nr_pages, > - struct vmem_altmap *altmap) > + struct vmem_altmap *altmap, struct dev_pagemap *pgmap) > { > unsigned long start = (unsigned long) pfn_to_page(pfn); > unsigned long end = start + nr_pages * sizeof(struct page); > @@ -746,7 +746,7 @@ static int fill_subsection_map(unsigned long pfn, unsigned long nr_pages) > * usage map, but still need to free the vmemmap range. > */ > static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > - struct vmem_altmap *altmap) > + struct vmem_altmap *altmap, struct dev_pagemap *pgmap) > { > struct mem_section *ms = __pfn_to_section(pfn); > bool section_is_early = early_section(ms); > @@ -784,7 +784,7 @@ static void section_deactivate(unsigned long pfn, unsigned long nr_pages, > * section_activate() and pfn_valid() . > */ > if (!section_is_early) > - depopulate_section_memmap(pfn, nr_pages, altmap); > + depopulate_section_memmap(pfn, nr_pages, altmap, pgmap); > else if (memmap) > free_map_bootmem(memmap); > > @@ -828,7 +828,7 @@ static struct page * __meminit section_activate(int nid, unsigned long pfn, > > memmap = populate_section_memmap(pfn, nr_pages, nid, altmap, pgmap); > if (!memmap) { > - section_deactivate(pfn, nr_pages, altmap); > + section_deactivate(pfn, nr_pages, altmap, pgmap); > return ERR_PTR(-ENOMEM); > } > > @@ -889,13 +889,13 @@ int __meminit sparse_add_section(int nid, unsigned long start_pfn, > } > > void sparse_remove_section(unsigned long pfn, unsigned long nr_pages, > - struct vmem_altmap *altmap) > + struct vmem_altmap *altmap, struct dev_pagemap *pgmap) While at it, could switch to two-tab indent here as well. Acked-by: David Hildenbrand (Arm) -- Cheers, David