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[80.187.83.189]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-46faf12fd83sm32079965e9.9.2025.10.09.00.19.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 09 Oct 2025 00:19:36 -0700 (PDT) Message-ID: Date: Thu, 9 Oct 2025 09:19:34 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/2] mm/compaction: check the range to pageblock_pfn_to_page() is within the zone first To: Wei Yang Cc: akpm@linux-foundation.org, vbabka@suse.cz, surenb@google.com, mhocko@suse.com, jackmanb@google.com, hannes@cmpxchg.org, ziy@nvidia.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, rppt@kernel.org, iamjoonsoo.kim@lge.com, linux-mm@kvack.org References: <20251002033140.24462-1-richard.weiyang@gmail.com> <20251002033140.24462-2-richard.weiyang@gmail.com> <99824e33-bf25-40ef-b969-a48e3b916ad1@redhat.com> <20251009020817.y7ji6wqhrv44h5uz@master> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZoEEwEIAEQCGwMCF4ACGQEFCwkIBwICIgIG FQoJCAsCBBYCAwECHgcWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaJzangUJJlgIpAAKCRBN 3hD3AP+DWhAxD/9wcL0A+2rtaAmutaKTfxhTP0b4AAp1r/eLxjrbfbCCmh4pqzBhmSX/4z11 opn2KqcOsueRF1t2ENLOWzQu3Roiny2HOU7DajqB4dm1BVMaXQya5ae2ghzlJN9SIoopTWlR 0Af3hPj5E2PYvQhlcqeoehKlBo9rROJv/rjmr2x0yOM8qeTroH/ZzNlCtJ56AsE6Tvl+r7cW 3x7/Jq5WvWeudKrhFh7/yQ7eRvHCjd9bBrZTlgAfiHmX9AnCCPRPpNGNedV9Yty2Jnxhfmbv Pw37LA/jef8zlCDyUh2KCU1xVEOWqg15o1RtTyGV1nXV2O/mfuQJud5vIgzBvHhypc3p6VZJ lEf8YmT+Ol5P7SfCs5/uGdWUYQEMqOlg6w9R4Pe8d+mk8KGvfE9/zTwGg0nRgKqlQXrWRERv cuEwQbridlPAoQHrFWtwpgYMXx2TaZ3sihcIPo9uU5eBs0rf4mOERY75SK+Ekayv2ucTfjxr Kf014py2aoRJHuvy85ee/zIyLmve5hngZTTe3Wg3TInT9UTFzTPhItam6dZ1xqdTGHZYGU0O otRHcwLGt470grdiob6PfVTXoHlBvkWRadMhSuG4RORCDpq89vu5QralFNIf3EysNohoFy2A LYg2/D53xbU/aa4DDzBb5b1Rkg/udO1gZocVQWrDh6I2K3+cCs7BTQRVy5+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: <20251009020817.y7ji6wqhrv44h5uz@master> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: o3FU09vFAx2OgRpRkg2AELrORDj804CO2cboV-edBio_1759994378 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: s4h8q439r6bcpm9pzdf8xymhf9bjcbm3 X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: BD1021C000C X-HE-Tag: 1759994382-93316 X-HE-Meta: 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 f7rGEfPY 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 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 09.10.25 04:08, Wei Yang wrote: > On Wed, Oct 08, 2025 at 12:14:25PM +0200, David Hildenbrand wrote: >> On 02.10.25 05:31, Wei Yang wrote: >>> Function pageblock_pfn_to_page() is introduced by commit 7d49d8868336 >>> ("mm, compaction: reduce zone checking frequency in the migration scanner"), >>> where there is no requirement on start_pfn/end_pfn except they are in >>> the same pageblock. >>> >>> So at that time, pageblock_pfn_to_page() would be passed with pfn >>> without compared with zone boundary. >>> >>> But after commit 7cf91a98e607 ("mm/compaction: speed up >>> pageblock_pfn_to_page() when zone is contiguous"), pageblock_pfn_to_page() >>> would think the range is valid and in the same zone if zone->contiguous, >>> even the range doesn't belong to this zone. >>> >>> For example, in fast_isolate_freepages(), min_pfn is assigned to >>> pageblock_start_pfn() and passed to pageblock_pfn_to_page() without >>> checking with zone_start_pfn. And mostly, the end_pfn is not checked >>> with zone_end_pfn() before using. >>> >>> To make this function robust, check the range is within the zone first. >>> >>> Fixes: 7cf91a98e607 ("mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous") >>> Signed-off-by: Wei Yang >>> Cc: Vlastimil Babka >>> Cc: Joonsoo Kim >>> --- >>> mm/internal.h | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/mm/internal.h b/mm/internal.h >>> index 38607b2821d9..8e1a3819c9f1 100644 >>> --- a/mm/internal.h >>> +++ b/mm/internal.h >>> @@ -724,6 +724,9 @@ extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn, >>> static inline struct page *pageblock_pfn_to_page(unsigned long start_pfn, >>> unsigned long end_pfn, struct zone *zone) >>> { >>> + if (start_pfn < zone->zone_start_pfn || end_pfn > zone_end_pfn(zone)) >>> + return NULL; >>> + >>> if (zone->contiguous) >>> return pfn_to_page(start_pfn); >> >> fast_isolate_around() adjusts the range to the zone boundaries before calling >> fast_isolate_around(). >> > > Correct. > >> isolate_migratepages_range(), isolate_freepages_range(), isolate_freepages() >> and isolate_migratepages similarly all seem to take the zone range into >> account as well. > > Maybe I missed something. > > isolate_freepages() takes care of the end_pfn, but I don't see it adjust > start_pfn. Or you mean low_pfn is already adjusted? > > isolate_freepages_range() / isolate_migratepages_range() just adjust start_pfn. > > isolate_migratepages() seems not adjust start_pfn nor end_pfn? > > Maybe I misunderstand you, would you mind giving more detail? > >> >> Only fast_isolate_freepages is a bit more tricky. It definitely takes the end >> into account. The start comes from cc->free_pfn but IIRC it's always above >> the zone_start_pfn. >> I don't recall all the details, but at least regarding ZONE_MOVABLE we make sure that the start is aligned to MAX_ORDER_NR_PAGES and that the size is aligned to MAX_ORDER_NR_PAGES, see find_zone_movable_pfns_for_nodes(). Note that MAX_ORDER_NR_PAGES >= PAGEBLOCK_NR_PAGES. I think the same is true for any other zone as well. (DMA / DMA32 etc should always be at suitable boundaries already IIRC). Note that memory hotplug always works in section granularity, and a section is always <= MAX_ORDER_NR_PAGES, so it's also guaranteed there. -- Cheers David / dhildenb