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imf12.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=ISOEqVa3; spf=pass (imf12.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=1770900162; a=rsa-sha256; cv=none; b=4UUmSTn1KbU7d44h0C5ycpDhu3xUyzj8zb6uh7riKOVK7nwwM6OZ48rMFy+U1rZcI0QCzy 3+Sqw48xUQprMQpQPl8v1Ack17FOd//TpuAxkfYVNBLwGaF1u8hFkFcByUw3uuDOdMOu/a MK6nfwp2F0SoqgF3gfXm+JE6IFMoZIE= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id D3BCB60010; Thu, 12 Feb 2026 12:42:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 48B75C4CEF7; Thu, 12 Feb 2026 12:42:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770900161; bh=wmTC1zu+zmunjiFksRhBkChGjxTo30uCWZ1S6ET6yuY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ISOEqVa3YZ/Gs/St4vAPo3iDSwGIKu0JbJijbAGxag/+gbsim8Whh2tTquG3A06z+ JZMlYovC0qX6jEecChJgzyRtvlSxKPWTN5e3M/XwwQ9fP+/cbXNQ7iRcmnLQVO2ENX IhWmc2SZCt7VwlxTwR33Y+fjNabKSjQc7WRffdu9AohH/wtbxianQ0a1tsfIVcY2a+ N22NVCBXxMd8HJNxZpp5DlKT9aDN5bO5wlvGFkT5GGID68d5E8sT7Y39N0Qq5Ao8tm JsGxwdMfPwRoL/HxYGBRUhd6H9iq355rDWpFui5n8G2D/L/BKbeXJug7Ch0jLwZfVr 1zFLCvbphdOQA== Message-ID: <94a21bda-5677-4949-a1df-3f0d90348021@kernel.org> Date: Thu, 12 Feb 2026 13:42:36 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] smaps: Report correct page sizes with THP To: Andi Kleen , linux-mm@kvack.org Cc: linux-fsdevel@vger.kernel.org, akpm@linux-foundation.org, willy@infradead.org References: <20260209201731.231667-1-ak@linux.intel.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: <20260209201731.231667-1-ak@linux.intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: q8rwzmr9ut1to5caiss5ypiah9hax4sp X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 78F8B4000C X-HE-Tag: 1770900162-317486 X-HE-Meta: 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 A7w6ksP6 B4pBV+C5I1f6iCkCpgftrtuGTopj04YBlzxbNLEGLh/Kdt7lPx723iNRseqef0hzqN5X75DBZBtfZrmbIc981P/BiaT5A1VD6d+2Sg0DOgFFDxjRh+qfYfKRS32YXqtaii7VnzMDhnljcSjNPWHvDSpKfvkSvge6ZUcLuZs30Fg3UBPRoTZO9b7VQYxZs1ALnaW8mVDXA/3cmynUiBOSYvDJZWcC1cuGBNB8/ZbIM5L8vTOeHnAl2V8SdK+HYBc5tSx8K3LSLVmsJsgdmVj0rWXR7lw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/9/26 21:17, Andi Kleen wrote: > Recently I wasted quite some time debugging why THP didn't work, when it > was just smaps always reporting the base page size. It has separate > counts for (non m) THP, but using them is not always obvious. For > standard THP the page sizes can be actually derived from the existing > counts, so do just do that. I left KernelPageSize alone. > The mixed page size case is reported with a new MMUPageSize2 item. > This doesn't do anything about mTHP reporting, but even the basic > smaps is not aware of it so far. > > Signed-off-by: Andi Kleen > --- > Documentation/filesystems/proc.rst | 2 +- > fs/proc/task_mmu.c | 14 +++++++++++++- > 2 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst > index 8256e857e2d7..7c776046d15a 100644 > --- a/Documentation/filesystems/proc.rst > +++ b/Documentation/filesystems/proc.rst > @@ -483,7 +483,7 @@ entries; the page size used by the MMU when backing a VMA (in most cases, > the same as KernelPageSize); the amount of the mapping that is currently > resident in RAM (RSS); the process's proportional share of this mapping > (PSS); and the number of clean and dirty shared and private pages in the > -mapping. > +mapping. If the mapping has multiple page size there might be a MMUPageSize2. > > The "proportional set size" (PSS) of a process is the count of pages it has > in memory, where each page is divided by the number of processes sharing it. > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index 26188a4ad1ab..9123e59dcf4c 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -1377,7 +1377,19 @@ static int show_smap(struct seq_file *m, void *v) > > SEQ_PUT_DEC("Size: ", vma->vm_end - vma->vm_start); > SEQ_PUT_DEC(" kB\nKernelPageSize: ", vma_kernel_pagesize(vma)); > - SEQ_PUT_DEC(" kB\nMMUPageSize: ", vma_mmu_pagesize(vma)); > + > + /* Only THP? */ > + if (mss.shmem_thp + mss.file_thp + mss.anonymous_thp == mss.resident && > + mss.resident > 0) { > + SEQ_PUT_DEC(" kB\nMMUPageSize: ", HPAGE_PMD_SIZE); > + } else { > + unsigned ps = vma_mmu_pagesize(vma); > + /* Will need adjustments when more THP page sizes are added. */ > + SEQ_PUT_DEC(" kB\nMMUPageSize: ", ps); > + if (mss.shmem_thp + mss.file_thp + mss.anonymous_thp > 0 && > + ps != HPAGE_PMD_SIZE) > + SEQ_PUT_DEC(" kB\nMMUPageSize2: ", HPAGE_PMD_SIZE); > + } > seq_puts(m, " kB\n"); > > __show_smap(m, &mss, false); We have AnonHugePages:, ShmemPmdMapped: and FilePmdMapped: that tell you exactly what you want to know. Especially the mixed thing is just nasty. Once we go into cont-pte territory (or automatic pte coalescing by hardware) it all gets confusing. Sorry, NAK. -- Cheers, David