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[2003:cb:c739:8e00:7a46:1b8c:8b13:d3d]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-432b05c202asm220556165e9.30.2024.11.12.08.19.33 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 12 Nov 2024 08:19:33 -0800 (PST) Message-ID: Date: Tue, 12 Nov 2024 17:19:32 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 3/5] mm: shmem: add large folio support for tmpfs To: Baolin Wang , akpm@linux-foundation.org, hughd@google.com Cc: willy@infradead.org, wangkefeng.wang@huawei.com, 21cnbao@gmail.com, ryan.roberts@arm.com, ioworker0@gmail.com, da.gomez@samsung.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: 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-MFC-PROC-ID: LwhyeGMa-DMpuPr-A7urK7sdj_J0K7HcEguDqmePbBw_1731428375 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: DB9A418000E X-Rspamd-Server: rspam01 X-Stat-Signature: 3g76ku3rh166fx4xkqkih5chmjuu6cfg X-HE-Tag: 1731428348-360814 X-HE-Meta: U2FsdGVkX1/Jxt0jRvbuXQCQWpNx1L3A/jPutrfeyLdXGYtmdVPrMM1CiaoE6egCBVyraiIHZDm1xwwDPTwY183RjSiLVvj2vbh82eg8FOWbLVYJvvFeD6UX59dEaxPHzhbVFjKfKl9LrfS2MbF4gL+wNfqRSR/rVmGvmSAgYN/Vv+QBX5JRxba4cXZfEglPj2f1E6plwPft1Us1FZ93abF/3Ez9L0SQRiabLz6+T5FR/iuX26hh3YuJ8upUUNFn2V5UPS0Pc+l714d8WFv39FQqaI9osVDxlvXvMaBTpcfWqV8gGgVA2Phzm9VpaoySyTP1mg8FL4474ArMV/sqtsDitl3kfVJgMjTO9JeXuS0iJ1V2WoV7MGDvsp5SCuUqkWKi7tadsoMwzPmCxdgFw70A8FfY4BU5rYzGSQBqsNJZPSnhNvckFukzscf+2X8LHMK07/8ROIYjU+gtBO5EesuNIP8TGAOycgoXMTGrfTZflgej1f6x0CMDJ5uI6xf+H0ZNRo9VczFsq0/OAkK2b8dj/HUsxxt1N/kT+XvHymaC/7KQpjXGUuG3wisLkrkmzAoI4ZqbE0UpoHa++bBG3MIdUhaJn6RrW3oe6HdfoPMhlb2VxSiwSDQCE5kA5f9snJGaUNBa+4VsJGAigp/+tCV1HYTYwB3gQAk274jGJR7O6qSeW0TBBrEevuNYz4aDS4zPB0K98GvzA4JIHRGBCev7sn6TWcd2DslqdKBbmpI3INBf3qDvp4jx9X7W5I7kY5q54l9HEJPmyKvEJWqojYjWLYDi5Ajf/F3WTr/v+gaPP1xMr7hl62G6UogkFJYZ6p0utqnoaoGiGy+mZNABIEGd3urgC2Gu4aBeTZUqY68hi0Qeaoy6GiARxCcu4IVxYhR00Vj7lXWAlJO4YxTecMW7k3wwFrufRkGzlYzbHtSDW71rUb3BcrmgJ6U3jH1PJgH5WkpzlYVGz38Fikh Kcu4YT+W RGAmm2GMcyTHoM/TwYH2+0DDfMOpCCfnmy+M34irhMwu+bvk/SWDJWj/ijcQK7w6r9R82yDCS7SmJJjuyaLnv8VDJxMLcRUx7Q+nI5luxgH7b2T3K2vsJ+kFxRpBL78bZu8HE6ytLEligkqqD0sFsyjuZ+kf3dze38hlRm4ww/fUcqclqqlYAT/LjK8G29BuSbvfktu3UeTLgL9TW1ugGFJR5lrIzFvddqISrCUS6rhstesP/8SnCCffaC93RjUw047RZzdB55RIDpZYm0T4YIArJrGhUJEY5GbpEaHd5MCMZ6j22X6ycXi54tZsEVZ1fGh1WLAsqLEjzQY6TMC9owUdJtpely2sFRNePOO49wCMmzUPRepsX5XH96vUdcyPY6dqViwvHqURsFfApPuPZm3uXLLSNUAyZbD8TJ9N/LGigMvCHEmrUN8ncotxXxUPqWKo4 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 12.11.24 08:45, Baolin Wang wrote: > Add large folio support for tmpfs write and fallocate paths matching the > same high order preference mechanism used in the iomap buffered IO path > as used in __filemap_get_folio(). > > Add shmem_mapping_size_orders() to get a hint for the orders of the folio > based on the file size which takes care of the mapping requirements. > > Traditionally, tmpfs only supported PMD-sized huge folios. However nowadays > with other file systems supporting any sized large folios, and extending > anonymous to support mTHP, we should not restrict tmpfs to allocating only > PMD-sized huge folios, making it more special. Instead, we should allow > tmpfs can allocate any sized large folios. > > Considering that tmpfs already has the 'huge=' option to control the huge > folios allocation, we can extend the 'huge=' option to allow any sized huge > folios. The semantics of the 'huge=' mount option are: > > huge=never: no any sized huge folios > huge=always: any sized huge folios > huge=within_size: like 'always' but respect the i_size > huge=advise: like 'always' if requested with fadvise()/madvise() > > Note: for tmpfs mmap() faults, due to the lack of a write size hint, still > allocate the PMD-sized huge folios if huge=always/within_size/advise is set. > > Moreover, the 'deny' and 'force' testing options controlled by > '/sys/kernel/mm/transparent_hugepage/shmem_enabled', still retain the same > semantics. The 'deny' can disable any sized large folios for tmpfs, while > the 'force' can enable PMD sized large folios for tmpfs. > > Co-developed-by: Daniel Gomez > Signed-off-by: Daniel Gomez > Signed-off-by: Baolin Wang > --- > mm/shmem.c | 91 +++++++++++++++++++++++++++++++++++++++++++++--------- > 1 file changed, 77 insertions(+), 14 deletions(-) > > diff --git a/mm/shmem.c b/mm/shmem.c > index 86b2e417dc6f..a3203cf8860f 100644 > --- a/mm/shmem.c > +++ b/mm/shmem.c > @@ -549,10 +549,50 @@ static bool shmem_confirm_swap(struct address_space *mapping, > > static int shmem_huge __read_mostly = SHMEM_HUGE_NEVER; > > +/** > + * shmem_mapping_size_orders - Get allowable folio orders for the given file size. > + * @mapping: Target address_space. > + * @index: The page index. > + * @write_end: end of a write, could extend inode size. > + * > + * This returns huge orders for folios (when supported) based on the file size > + * which the mapping currently allows at the given index. The index is relevant > + * due to alignment considerations the mapping might have. The returned order > + * may be less than the size passed. > + * > + * Return: The orders. > + */ > +static inline unsigned int > +shmem_mapping_size_orders(struct address_space *mapping, pgoff_t index, loff_t write_end) > +{ > + unsigned int order; > + size_t size; > + > + if (!mapping_large_folio_support(mapping) || !write_end) > + return 0; > + > + /* Calculate the write size based on the write_end */ > + size = write_end - (index << PAGE_SHIFT); > + order = filemap_get_order(size); > + if (!order) > + return 0; > + > + /* If we're not aligned, allocate a smaller folio */ > + if (index & ((1UL << order) - 1)) > + order = __ffs(index); > + > + order = min_t(size_t, order, MAX_PAGECACHE_ORDER); > + return order > 0 ? BIT(order + 1) - 1 : 0; > +} > + > static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index, > loff_t write_end, bool shmem_huge_force, > + struct vm_area_struct *vma, > unsigned long vm_flags) > { > + unsigned long within_size_orders; > + unsigned int order; > + pgoff_t aligned_index; > loff_t i_size; > > if (HPAGE_PMD_ORDER > MAX_PAGECACHE_ORDER) We can allow all orders up to MAX_PAGECACHE_ORDER, shmem_mapping_size_orders() handles it properly. So maybe we should drop this condition and use instead below where we have return BIT(HPAGE_PMD_ORDER); instead something like. return HPAGE_PMD_ORDER > MAX_PAGECACHE_ORDER ? 0 : BIT(HPAGE_PMD_ORDER); Ideally, factoring it out somehow int maybe_pmd_order = HPAGE_PMD_ORDER > MAX_PAGECACHE_ORDER ? 0 : BIT(HPAGE_PMD_ORDER); ... return maybe_pmd_order; > @@ -564,15 +604,41 @@ static unsigned int shmem_huge_global_enabled(struct inode *inode, pgoff_t index > if (shmem_huge_force || shmem_huge == SHMEM_HUGE_FORCE) > return BIT(HPAGE_PMD_ORDER); Why not force-enable all orders (of course, respecting MAX_PAGECACHE_ORDER and possibly VMA)? > > + /* > + * The huge order allocation for anon shmem is controlled through > + * the mTHP interface, so we still use PMD-sized huge order to > + * check whether global control is enabled. > + * > + * For tmpfs mmap()'s huge order, we still use PMD-sized order to > + * allocate huge pages due to lack of a write size hint. > + * > + * Otherwise, tmpfs will allow getting a highest order hint based on > + * the size of write and fallocate paths, then will try each allowable > + * huge orders. > + */ > switch (SHMEM_SB(inode->i_sb)->huge) { > case SHMEM_HUGE_ALWAYS: > - return BIT(HPAGE_PMD_ORDER); > - case SHMEM_HUGE_WITHIN_SIZE: > - index = round_up(index + 1, HPAGE_PMD_NR); > - i_size = max(write_end, i_size_read(inode)); > - i_size = round_up(i_size, PAGE_SIZE); > - if (i_size >> PAGE_SHIFT >= index) > + if (vma) > return BIT(HPAGE_PMD_ORDER); > + > + return shmem_mapping_size_orders(inode->i_mapping, index, write_end); > + case SHMEM_HUGE_WITHIN_SIZE: > + if (vma) > + within_size_orders = BIT(HPAGE_PMD_ORDER); > + else > + within_size_orders = shmem_mapping_size_orders(inode->i_mapping, > + index, write_end); > + > + order = highest_order(within_size_orders); > + while (within_size_orders) { > + aligned_index = round_up(index + 1, 1 << order); > + i_size = max(write_end, i_size_read(inode)); > + i_size = round_up(i_size, PAGE_SIZE); > + if (i_size >> PAGE_SHIFT >= aligned_index) > + return within_size_orders; > + > + order = next_order(&within_size_orders, order); > + } > fallthrough; > case SHMEM_HUGE_ADVISE: > if (vm_flags & VM_HUGEPAGE) I think the point here is that "write" -> no VMA -> vm_flags == 0 -> no code changes needed :) -- Cheers, David / dhildenb