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[2003:cb:c70d:fb00:d3ed:5f44:1b2d:12af]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-43993847f39sm13967905e9.14.2025.02.18.00.52.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 18 Feb 2025 00:52:37 -0800 (PST) Message-ID: <4195424c-3147-402f-bb73-4f7b96f6a9bf@redhat.com> Date: Tue, 18 Feb 2025 09:52:35 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH V2] mm/hugetlb: wait for hugepage folios to be freed To: Muchun Song , yangge1116@126.com Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, 21cnbao@gmail.com, baolin.wang@linux.alibaba.com, osalvador@suse.de, liuzixing@hygon.cn References: <1739604026-2258-1-git-send-email-yangge1116@126.com> <574F9D6A-F370-4A8C-9044-BC0A6189F055@linux.dev> 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 ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: <574F9D6A-F370-4A8C-9044-BC0A6189F055@linux.dev> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: JrEufoZvUM7gAZ2xRGL8N7GFiQ3iI6FzLR4rhxS1OMA_1739868759 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 3A2D38000D X-Stat-Signature: hrqe9wk81k9wmgffpnprm9eaksp3wpjo X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1739868762-146561 X-HE-Meta: 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 e0+fGiWU 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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 18.02.25 07:52, Muchun Song wrote: > > >> On Feb 15, 2025, at 15:20, yangge1116@126.com wrote: >> >> From: Ge Yang >> >> Since the introduction of commit b65d4adbc0f0 ("mm: hugetlb: defer freeing >> of HugeTLB pages"), which supports deferring the freeing of HugeTLB pages, >> the allocation of contiguous memory through cma_alloc() may fail >> probabilistically. >> >> In the CMA allocation process, if it is found that the CMA area is >> occupied >> by in-use hugepage folios, these in-use hugepage folios need to be >> migrated >> to another location. When there are no available hugepage folios in the >> free HugeTLB pool during the migration of in-use HugeTLB pages, new folios >> are allocated from the buddy system. A temporary state is set on the newly >> allocated folio. Upon completion of the hugepage folio migration, the >> temporary state is transferred from the new folios to the old folios. >> Normally, when the old folios with the temporary state are freed, it is >> directly released back to the buddy system. However, due to the deferred >> freeing of HugeTLB pages, the PageBuddy() check fails, ultimately leading >> to the failure of cma_alloc(). >> >> Here is a simplified call trace illustrating the process: >> cma_alloc() >>    ->__alloc_contig_migrate_range() // Migrate in-use hugepage >>        ->unmap_and_move_huge_page() >>            ->folio_putback_hugetlb() // Free old folios >>    ->test_pages_isolated() >>        ->__test_page_isolated_in_pageblock() >>             ->PageBuddy(page) // Check if the page is in buddy >> >> To resolve this issue, we have implemented a function named >> wait_for_hugepage_folios_freed(). This function ensures that the hugepage >> folios are properly released back to the buddy system after their >> migration >> is completed. By invoking wait_for_hugepage_folios_freed() before calling >> PageBuddy(), we ensure that PageBuddy() will succeed. >> >> Fixes: b65d4adbc0f0 ("mm: hugetlb: defer freeing of HugeTLB pages") >> Signed-off-by: Ge Yang >> --- >> >> V2: >> - flush all folios at once suggested by David >> >> include/linux/hugetlb.h |  5 +++++ >> mm/hugetlb.c            |  8 ++++++++ >> mm/page_isolation.c     | 10 ++++++++++ >> 3 files changed, 23 insertions(+) >> >> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h >> index 6c6546b..04708b0 100644 >> --- a/include/linux/hugetlb.h >> +++ b/include/linux/hugetlb.h >> @@ -697,6 +697,7 @@ bool hugetlb_bootmem_page_zones_valid(int nid, >> struct huge_bootmem_page *m); >> >> int isolate_or_dissolve_huge_page(struct page *page, struct list_head >> *list); >> int replace_free_hugepage_folios(unsigned long start_pfn, unsigned >> long end_pfn); >> +void wait_for_hugepage_folios_freed(void); >> struct folio *alloc_hugetlb_folio(struct vm_area_struct *vma, >>                unsigned long addr, bool cow_from_owner); >> struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int >> preferred_nid, >> @@ -1092,6 +1093,10 @@ static inline int >> replace_free_hugepage_folios(unsigned long start_pfn, >>    return 0; >> } >> >> +static inline void wait_for_hugepage_folios_freed(void) >> +{ >> +} >> + >> static inline struct folio *alloc_hugetlb_folio(struct vm_area_struct >> *vma, >>                       unsigned long addr, >>                       bool cow_from_owner) >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index 30bc34d..36dd3e4 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -2955,6 +2955,14 @@ int replace_free_hugepage_folios(unsigned long >> start_pfn, unsigned long end_pfn) >>    return ret; >> } >> >> +void wait_for_hugepage_folios_freed(void) > > We usually use the "hugetlb" term now instead of "huge_page" to > differentiate with THP. So I suggest naming it as > wait_for_hugetlb_folios_freed(). Maybe "wait_for_freed_hugetlb_folios" or "hugetlb_wait_for_freed_folios". In general, LGTM -- Cheers, David / dhildenb