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[2003:cb:c703:fe00:10fe:298:6bf1:d163]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3607509348esm1089278f8f.17.2024.06.13.02.12.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 13 Jun 2024 02:12:12 -0700 (PDT) Message-ID: Date: Thu, 13 Jun 2024 11:12:10 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC 3/3] mm: remove folio_test_anon(folio)==false path in __folio_add_anon_rmap() To: Barry Song <21cnbao@gmail.com> Cc: akpm@linux-foundation.org, linux-mm@kvack.org, chrisl@kernel.org, linux-kernel@vger.kernel.org, mhocko@suse.com, ryan.roberts@arm.com, baolin.wang@linux.alibaba.com, yosryahmed@google.com, shy828301@gmail.com, surenb@google.com, v-songbaohua@oppo.com, willy@infradead.org, ying.huang@intel.com, yuzhao@google.com References: <20240613000721.23093-1-21cnbao@gmail.com> <20240613000721.23093-4-21cnbao@gmail.com> 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: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Stat-Signature: khfbbs83se6r8zrmrdmq6gfg6cmoqp8w X-Rspamd-Queue-Id: AFDB540016 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1718269937-689694 X-HE-Meta: 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 YgyX0qR+ 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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 13.06.24 11:06, Barry Song wrote: > On Thu, Jun 13, 2024 at 8:49 PM David Hildenbrand wrote: >> >> On 13.06.24 10:46, Barry Song wrote: >>> On Thu, Jun 13, 2024 at 12:08 PM Barry Song <21cnbao@gmail.com> wrote: >>>> >>>> From: Barry Song >>>> >>>> The folio_test_anon(folio)==false case within do_swap_page() has been >>>> relocated to folio_add_new_anon_rmap(). Additionally, two other callers >>>> consistently pass anonymous folios. >>>> >>>> stack 1: >>>> remove_migration_pmd >>>> -> folio_add_anon_rmap_pmd >>>> -> __folio_add_anon_rmap >>>> >>>> stack 2: >>>> __split_huge_pmd_locked >>>> -> folio_add_anon_rmap_ptes >>>> -> __folio_add_anon_rmap >>>> >>>> __folio_add_anon_rmap() only needs to handle the cases >>>> folio_test_anon(folio)==true now. >>> >>> My team reported a case where swapoff() is calling >>> folio_add_anon_rmap_pte *not* folio_add_anon_rmap_ptes >>> with one new anon (!folio_test_anon(folio)). >>> >>> I will double check all folio_add_anon_rmap_pte() cases. >> >> Right, swapoff() path is a bit special (e.g., we don't do any kind of >> batching on the swapoff() path). >> >> But we should never get a new large anon folio there, or could that now >> happen? > > My team encountered the following issue while testing this RFC > series on real hardware. Let me take a look to identify the > problem. > > [ 261.214195][T11285] page:000000004cdd779e refcount:4 mapcount:1 > mapping:00000000ba142c22 index:0x1 pfn:0x1b30a6 > [ 261.214213][T11285] memcg:ffffff8003678000 > [ 261.214217][T11285] aops:swap_aops > [ 261.214233][T11285] flags: > 0x2000000000081009(locked|uptodate|owner_priv_1|swapbacked|zone=1|kasantag=0x0) > [ 261.214241][T11285] page_type: 0x0() > [ 261.214246][T11285] raw: 2000000000081009 0000000000000000 > dead000000000122 0000000000000000 > [ 261.214251][T11285] raw: 0000000000000001 00000000000d84b3 > 0000000400000000 ffffff8003678000 > [ 261.214254][T11285] page dumped because: > VM_WARN_ON_FOLIO(!folio_test_anon(folio)) > [ 261.214257][T11285] page_owner tracks the page as allocated > [ 261.214260][T11285] page last allocated via order 0, migratetype > Movable, gfp_mask 0x2140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid > 11285, tgid 11285 (swapoff), ts 261214177545, free_ts 261151875699 > [ 261.214268][T11285] post_alloc_hook+0x1b8/0x1c0 > [ 261.214284][T11285] prep_new_page+0x28/0x13c > [ 261.214291][T11285] get_page_from_freelist+0x198c/0x1aa4 > [ 261.214298][T11285] __alloc_pages+0x15c/0x330 > [ 261.214304][T11285] __folio_alloc+0x1c/0x4c > [ 261.214310][T11285] __read_swap_cache_async+0xd8/0x48c > [ 261.214320][T11285] swap_cluster_readahead+0x158/0x324 > [ 261.214326][T11285] swapin_readahead+0x64/0x448 > [ 261.214331][T11285] __arm64_sys_swapoff+0x6ec/0x14b0 > [ 261.214337][T11285] invoke_syscall+0x58/0x114 > [ 261.214353][T11285] el0_svc_common+0xac/0xe0 > [ 261.214360][T11285] do_el0_svc+0x1c/0x28 > [ 261.214366][T11285] el0_svc+0x38/0x68 > [ 261.214372][T11285] el0t_64_sync_handler+0x68/0xbc > [ 261.214376][T11285] el0t_64_sync+0x1a8/0x1ac > [ 261.214381][T11285] page last free pid 90 tgid 90 stack trace: > [ 261.214386][T11285] free_unref_page_prepare+0x338/0x374 > [ 261.214395][T11285] free_unref_page_list+0x84/0x378 > [ 261.214400][T11285] shrink_folio_list+0x1234/0x13e4 > [ 261.214409][T11285] evict_folios+0x1458/0x19b4 > [ 261.214417][T11285] try_to_shrink_lruvec+0x1c8/0x264 > [ 261.214422][T11285] shrink_one+0xa8/0x234 > [ 261.214427][T11285] shrink_node+0xb38/0xde0 > [ 261.214432][T11285] balance_pgdat+0x7a4/0xdb4 > [ 261.214437][T11285] kswapd+0x290/0x4e4 > [ 261.214442][T11285] kthread+0x114/0x1bc > [ 261.214459][T11285] ret_from_fork+0x10/0x20 > [ 261.214477][T11285] ------------[ cut here ]------------ > [ 261.214480][T11285] WARNING: CPU: 3 PID: 11285 at mm/rmap.c:1305 > folio_add_anon_rmap_ptes+0x2b4/0x330 > > [ 261.215403][T11285] pstate: 63400005 (nZCv daif +PAN -UAO +TCO +DIT > -SSBS BTYPE=--) > [ 261.215423][T11285] pc : folio_add_anon_rmap_ptes+0x2b4/0x330 > [ 261.215428][T11285] lr : folio_add_anon_rmap_ptes+0x2b4/0x330 > [ 261.215433][T11285] sp : ffffffc0a7dbbbf0 > [ 261.215437][T11285] x29: ffffffc0a7dbbbf0 x28: ffffff8040860a08 > x27: ffffff80db480000 > [ 261.215445][T11285] x26: fffffffe04cc2980 x25: ffffff808f77f120 > x24: 0000007b44941000 > [ 261.215452][T11285] x23: 0000000000000001 x22: 0000000000000001 > x21: fffffffe04cc2980 > [ 261.215459][T11285] x20: ffffff80db480000 x19: fffffffe04cc2980 > x18: ffffffed011dae80 > [ 261.215465][T11285] x17: 0000000000000001 x16: ffffffffffffffff > x15: 0000000000000004 > [ 261.215471][T11285] x14: ffffff82fb73fac0 x13: 0000000000000003 > x12: 0000000000000003 > [ 261.215476][T11285] x11: 00000000fffeffff x10: c0000000fffeffff x9 > : 0d46c0889b468e00 > [ 261.215483][T11285] x8 : 0d46c0889b468e00 x7 : 545b5d3935343431 x6 > : 322e31363220205b > [ 261.215489][T11285] x5 : ffffffed013de407 x4 : ffffffed00698967 x3 > : 0000000000000000 > [ 261.215495][T11285] x2 : 0000000000000000 x1 : ffffffc0a7dbb8c0 x0 > : ffffff8068c15c80 > [ 261.215501][T11285] Call trace: > [ 261.215504][T11285] folio_add_anon_rmap_ptes+0x2b4/0x330 > [ 261.215509][T11285] __arm64_sys_swapoff+0x8cc/0x14b0 > [ 261.215516][T11285] invoke_syscall+0x58/0x114 > [ 261.215526][T11285] el0_svc_common+0xac/0xe0 > [ 261.215532][T11285] do_el0_svc+0x1c/0x28 > [ 261.215539][T11285] el0_svc+0x38/0x68 > [ 261.215544][T11285] el0t_64_sync_handler+0x68/0xbc > [ 261.215548][T11285] el0t_64_sync+0x1a8/0x1ac > [ 261.215552][T11285] ---[ end trace 0000000000000000 ]--- Ah, yes. in unuse_pte(), you'll have to do the right thing if !folio_test(anon) before doing the folio_add_anon_rmap_pte(). You might have a fresh anon folio in the swapcache that was never mapped (hopefully order-0, otherwise we'd likely be in trouble). -- Cheers, David / dhildenb