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charset=us-ascii Content-Disposition: inline In-Reply-To: <8297c4d3-f97b-4923-9b27-19294fa130eb@redhat.com> User-Agent: NeoMutt/20170113 (1.7.2) X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 431B6140020 X-Stat-Signature: gfqpxw6wmqfr71uabj1dmo1a61ipuu58 X-HE-Tag: 1717444886-148489 X-HE-Meta: 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 3KWWqnWm 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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 Mon, Jun 03, 2024 at 10:55:10AM +0200, David Hildenbrand wrote: >On 02.06.24 02:58, Wei Yang wrote: >> On Sat, Jun 01, 2024 at 06:15:33PM +0200, David Hildenbrand wrote: >> > On 01.06.24 17:32, David Hildenbrand wrote: >> > > On 01.06.24 15:34, Wei Yang wrote: >> > > > Total memory represents pages managed by buddy system. >> > > >> > > No, that's managed pages. >> > > >> > > > After the >> > > > introduction of DEFERRED_STRUCT_PAGE_INIT, it may count the pages before >> > > > being managed. >> > > > >> > > >> > > I recall one reason that is done, so other subsystem know the total >> > > memory size even before deferred init is done. >> > > >> > > > free_low_memory_core_early() returns number of pages for all free pages, >> > > > even at this moment only early initialized pages are freed to buddy >> > > > system. This means the total memory at this moment is not correct. >> > > > >> > > > Let's increase it when pages are freed to buddy system. >> > > >> > > I'm missing the "why", and the very first sentence of this patch is wrong. >> > >> > Correction: your statement was correct :) That's why >> > adjust_managed_page_count() adjusts that as well. >> > >> > __free_pages_core() only adjusts managed page count, because it assumes >> > totalram has already been adjusted early during boot. >> > >> > The reason we have this split for now, I think, is because of subsystems that >> > call totalram_pages() during init. >> > >> > So the "why" question remains, because this change has the potential to break >> > other stuff. >> > >> >> Thanks, I didn't notice this. > >I think having your cleanup would be very nice, as I have patches in the >works that would benefit from being able to move the totalram update from >memory hotplug code to __free_pages_core(). > I got the same feeling. >We'd have to make sure that no code relies on totalram being sane/fixed >during boot for the initial memory. I think right now we might have such >code. > One concern is totalram would change when hotplug is enabled. That sounds those codes should do some re-calculation after totalram changes? >Further, we currently require only a single atomic RMW instruction to adjust >totalram during boot, moving it to __free_pages_core() would imply more >atomics: but usually only one per MAX_ORDER page, so I doubt this would make >a big difference. > I took a rough calculation on this.One MAX_ORDER page accounts for 2MB, and with defer_init only low zone's memory is initialized during boot. Per my understanding, low zone's memory is 4GB for x86. So the extra calculation is 4GB / 2MB = 2K. >-- >Cheers, > >David / dhildenb -- Wei Yang Help you, Help me