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b=XQHM9uVa9hZuc4Tlb9fIE7zYIL7/BBftidq4d5NM0JDfiuXyKd0sBUwKbumSINvUV Du3szP9dLJnRM5X5H1nhy/ffQ1397bX/UNP4AxExFTRnHQar5pnKtTOxXfJ2aKd4eL cCt663qZgIGl+GqWnDtlvtnGk8TMXSU1koVpcGv/4mIVoRSPHZRhFQzq9//XZGeh7G IxFgK6dDO6o1nlHacMhiLZ//X8VFX7412Sb4Va/+JSkcuZzEMbiYrBP6r+uBkcBgQY qHlY/A7lHBOdQnKq6FpcLqM9oRWfyF21LTR5ZBuVCw7rvW6uCqM2YHUq5scQqCxNM/ IOnwezv/zfW5w== Message-ID: Date: Wed, 1 Apr 2026 10:32:30 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm/page_io: use sio->len for PSWPIN accounting in sio_read_complete() To: David Carlier , Barry Song <21cnbao@gmail.com>, Kairui Song , Chris Li , Andrew Morton , Kemeng Shi , Nhat Pham , Baoquan He , Youngjun Park , NeilBrown Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20260330071229.14614-1-devnexen@gmail.com> <20260401074753.238053-1-devnexen@gmail.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: <20260401074753.238053-1-devnexen@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 52962180005 X-Stat-Signature: iy9xbe3hc5beik8sy5cj8urho7q9eaqu X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1775032357-780567 X-HE-Meta: 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 htK8XK5X 0HSn+mrJNRc29YHM= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/1/26 09:47, David Carlier wrote: > sio_read_complete() uses sio->pages to account global PSWPIN vm events, > but sio->pages tracks the number of bvec entries (folios), not base > pages. > > While large folios cannot currently reach this path (SWP_FS_OPS and > SWP_SYNCHRONOUS_IO are mutually exclusive, and mTHP swap-in allocation > is gated on SWP_SYNCHRONOUS_IO), the accounting is semantically > inconsistent with the per-memcg path which correctly uses > folio_nr_pages(). > > Use sio->len >> PAGE_SHIFT instead, which gives the correct base page > count since sio->len is accumulated via folio_size(folio). > > Signed-off-by: David Carlier For the next time: Please don't send new revisions as reply to other revisions :) > --- > mm/page_io.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/page_io.c b/mm/page_io.c > index 63b262f4c5a9..1389cd57ca88 100644 > --- a/mm/page_io.c > +++ b/mm/page_io.c > @@ -497,7 +497,7 @@ static void sio_read_complete(struct kiocb *iocb, long ret) > folio_mark_uptodate(folio); > folio_unlock(folio); > } > - count_vm_events(PSWPIN, sio->pages); > + count_vm_events(PSWPIN, sio->len >> PAGE_SHIFT); > } else { > for (p = 0; p < sio->pages; p++) { > struct folio *folio = page_folio(sio->bvec[p].bv_page); sio->len always covers full pages as processed in swap_read_folio_fs(), so there should not be any difference. Acked-by: David Hildenbrand (Arm) -- Cheers, David