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b=FizDL4msF5tdF1c1h/MXNDlCvvdnN+5sk5lqksan2OqVLq/gNqCO7YNN9uo1F86Si V2ygNccvJtykvL6N/RTJkeO8sI/UXcKUcIu/D/BIWgtLfaQ+R204c0Na2ZAQaZSm0i MKCZCNdY+8lwjXYcZcO7tge62dL1ZH/lOPunYjwsN1QUb0JF7OsfOJXs9r4bdbcz/O tjO66q2fU7MFHRgvZ8PFu3o1MBnHn1KGRvkwbdizCjcvRRKR5NpU9CQ3Mf5k7NXZLZ m3X0Fv5659wEjqvr7k6K1CulVC1npPcugwqOe6j6d5gmj4Sd15FEb/d0G6lue+C+1d jivMx2TuJG9HQ== Date: Tue, 9 Jul 2024 11:42:20 +0300 From: Mike Rapoport To: Wei Yang Cc: akpm@linux-foundation.org, brauner@kernel.org, oleg@redhat.com, tandersen@netflix.com, mjguzik@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Hildenbrand Subject: Re: [PATCH v5 1/3] mm/memblock: introduce a new helper memblock_estimated_nr_free_pages() Message-ID: References: <20240709023609.21332-1-richard.weiyang@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240709023609.21332-1-richard.weiyang@gmail.com> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 8A7B12001C X-Stat-Signature: 561m6qkk7qef3fhctiytmfc1d1gnxcuy X-Rspam-User: X-HE-Tag: 1720514710-514836 X-HE-Meta: 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 b4fzp3He 21UeUYkb5VlUvDHyrfwdAvbz/JCrHI7reuASkm3Zr8oAqigf8bIxXeyRakYi/4poEb4rj9EPWq+oOTRMH6OXP335t2waFtv3BbuwBRARb2YrnDH7o8o9Idu6ORVJVzz/moQs1nV6zzPM6ZjxYh/kposeK61QOtO0+C32tUOQaehcp2IV5nfuJOcDhO1RX55gKDTKzms90oicQzRnqgP7gGECb/m+I3v907XJXEQI8lNWS3FHImdGhMpTIY028qcshCokx1Po0pEPTyeOgY8ibqyiy/FXOgsCDWGpEMjo/xNZg8L6vPai9oKkWCjnrOeaEbGipLZbXXh6JRuITjK66Uvha/bMfc8XlC3ZL19rCSDRkmKuZKDwCFH0ZGUni3TA/gA+/7kyvVQOnemXzL+VDP3eN+DA9wLOMEdocBL3PveMMz+83apsdlNyfJYKMhTo/iC47 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 Tue, Jul 09, 2024 at 02:36:07AM +0000, Wei Yang wrote: > 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 > Reviewed-by: David Hildenbrand Reviewed-by: Mike Rapoport > > --- > v5: cleanup the stale name > v4: adjust comment per david's suggestion > --- > include/linux/memblock.h | 1 + > mm/memblock.c | 17 +++++++++++++++++ > 2 files changed, 18 insertions(+) > > diff --git a/include/linux/memblock.h b/include/linux/memblock.h > index 40c62aca36ec..aba7ed9f2531 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_free_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..ae8e58fc4e7f 100644 > --- a/mm/memblock.c > +++ b/mm/memblock.c > @@ -1729,6 +1729,23 @@ 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, 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. > + * > + * Return: > + * An estimated number of free pages from memblock point of view. > + */ > +unsigned long __init memblock_estimated_nr_free_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 > -- Sincerely yours, Mike.