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[2003:cb:c72f:c00:10f0:d1a8:c206:17ac]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4264a1d0b19sm121218575e9.10.2024.07.07.01.17.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 07 Jul 2024 01:17:28 -0700 (PDT) Message-ID: <9f38e4f1-0ad3-4cd4-bcb7-5ec287859051@redhat.com> Date: Sun, 7 Jul 2024 10:17:27 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 1/3] mm/memblock: introduce a new helper memblock_estimated_nr_pages() To: Wei Yang , Mike Rapoport Cc: akpm@linux-foundation.org, brauner@kernel.org, oleg@redhat.com, mjguzik@gmail.com, tandersen@netflix.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20240703005151.28712-1-richard.weiyang@gmail.com> <20240706012805.uuvysz2qgapgqj6p@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 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: <20240706012805.uuvysz2qgapgqj6p@master> 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: 7bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 9A6B0C000F X-Stat-Signature: x6cpq9acx4qz999ehwtkosut3q3swnjh X-Rspam-User: X-HE-Tag: 1720340253-903960 X-HE-Meta: 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 r6PT2xMR weoUJN+iSlPXC4I3wu8qjB5xNmAWKDux2ctLTTljIjWxDKS99tsQQHT5t0XgChkdpULcYNSC96Zx0chCxKGGJ3sjAnoIFN7l+sQ7ZVg2plGICB//SBUQd9t36Ao8YGz5D8Ck7ebEPkmj1Yg16ZpvTpygT2fsOV9+++HGPgQs2Ra5+ECosha+SnOAz388Hi9+omjj8C930TfpVcSKCW6mSrJse/SwdceURKN2cUqY/O1ibXdDKpwhtBnviddFhdHlMZL6CCh1N617WaHahrAi7V223LWd3giuN8ruL54vnGIop5g1cSkn9IWSxS96a494U9SJ3VlZkzQGLCVCTuaoMv4QZXV5JepGYEBhbGYIah4+Aqmxu98cdyV9EfE+vo4OC5uplMgYCmM0cYL/CJFmzIaC4rxTtIw6X7x1B3RasB55kVjRxayTAq1W8/MMAOwWSwGfGMa3QkPWR8QhbzRGa3SjDD1rJ1HwT93vOgFjpcmh8AOU= 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 06.07.24 03:28, Wei Yang wrote: > On Fri, Jul 05, 2024 at 12:09:48PM +0300, Mike Rapoport wrote: >> On Wed, Jul 03, 2024 at 12:51:49AM +0000, Wei Yang wrote: >>> Instead of using raw memblock api, we wrap a new helper for user. >> >> The changelog should be more elaborate and explain why this function is >> needed. >> >>> Signed-off-by: Wei Yang >>> --- >>> include/linux/memblock.h | 1 + >>> mm/memblock.c | 19 +++++++++++++++++++ >>> 2 files changed, 20 insertions(+) >>> >>> diff --git a/include/linux/memblock.h b/include/linux/memblock.h >>> index 40c62aca36ec..7d1c32b3dc12 100644 >>> --- a/include/linux/memblock.h >>> +++ b/include/linux/memblock.h >>> @@ -486,6 +486,7 @@ static inline __init_memblock bool memblock_bottom_up(void) >>> >>> phys_addr_t memblock_phys_mem_size(void); >>> phys_addr_t memblock_reserved_size(void); >>> +unsigned long memblock_estimated_nr_pages(void); >>> phys_addr_t memblock_start_of_DRAM(void); >>> phys_addr_t memblock_end_of_DRAM(void); >>> void memblock_enforce_memory_limit(phys_addr_t memory_limit); >>> diff --git a/mm/memblock.c b/mm/memblock.c >>> index e81fb68f7f88..c1f1aac0459f 100644 >>> --- a/mm/memblock.c >>> +++ b/mm/memblock.c >>> @@ -1729,6 +1729,25 @@ phys_addr_t __init_memblock memblock_reserved_size(void) >>> return memblock.reserved.total_size; >>> } >>> >>> +/** >>> + * memblock_estimated_nr_pages - return number of pages from memblock point of >>> + * view >> >> This function returns the estimate for free pages, not the number of pages >> in RAM. >> >> How about memblock_estimated_nr_free_pages()? >> >>> + * some calculation before all pages are freed to buddy system, especially >>> + * when CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled. >> >> I'm failing to parse this sentence. The return value here won't depend on >> CONFIG_DEFERRED_STRUCT_PAGE_INIT. >> >>> + * >>> + * At this point, we can get this information from memblock. Since the system >>> + * state is not settle down and address alignment, the value is an estimation. >>> + * >>> + * Return: >>> + * An estimated number of pages from memblock point of view. >> >> ^ free >> >>> + */ >>> +unsigned long __init memblock_estimated_nr_pages(void) >>> +{ >>> + return PHYS_PFN(memblock_phys_mem_size() - memblock_reserved_size()); >>> +} >>> + >>> /* lowest address */ >>> phys_addr_t __init_memblock memblock_start_of_DRAM(void) >>> { >>> -- >>> 2.34.1 >>> > > Thanks for review. Is this one looks better? > > Subject: [PATCH] mm/memblock: introduce a new helper memblock_estimated_nr_free_pages() > > During bootup, system may need the number of free pages in the whole system > to do some calculation before all pages are freed to buddy system. Usually > this number is get from totalram_pages(). Since we plan to move the free > pages accounting in __free_pages_core(), this value may not represent > total free pages at the early stage, especially when > CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled. > > Instead of using raw memblock api, let's introduce a new helper for user > to get the estimated number of free pages from memblock point of view. > > Signed-off-by: Wei Yang > CC: David Hildenbrand > --- > include/linux/memblock.h | 1 + > mm/memblock.c | 22 ++++++++++++++++++++++ > 2 files changed, 23 insertions(+) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index 40c62aca36ec..7d1c32b3dc12 100644 > --- a/include/linux/memblock.h > +++ b/include/linux/memblock.h > @@ -486,6 +486,7 @@ static inline __init_memblock bool memblock_bottom_up(void) > > phys_addr_t memblock_phys_mem_size(void); > phys_addr_t memblock_reserved_size(void); > +unsigned long memblock_estimated_nr_pages(void); > phys_addr_t memblock_start_of_DRAM(void); > phys_addr_t memblock_end_of_DRAM(void); > void memblock_enforce_memory_limit(phys_addr_t memory_limit); > diff --git a/mm/memblock.c b/mm/memblock.c > index e81fb68f7f88..00decc42e02b 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -1729,6 +1729,28 @@ phys_addr_t __init_memblock memblock_reserved_size(void) > return memblock.reserved.total_size; > } > > +/** > + * memblock_estimated_nr_free_pages - return estimated number of free pages > + * from memblock point of view > + * > + * During bootup, system may need the number of free pages in the whole system > + * to do some calculation before all pages are freed to buddy system. Usually > + * this number is get from totalram_pages(). Since we plan to move the free > + * pages accounting in __free_pages_core(), this value may not represent total > + * free pages at the early stage, especially when > + * CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled. These historical details should be dropped. "Since we plan ..." will easily get outdated soon. * During bootup, subsystems might need a rough estimate of the number of * free pages in the whole system, before precise numbers are available * from the buddy. Especially with CONFIG_DEFERRED_STRUCT_PAGE_INIT, the * numbers obtained from the buddy might be very imprecise during bootup. ? Reviewed-by: David Hildenbrand -- Cheers, David / dhildenb