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Howlett" , Suren Baghdasaryan , Michal Hocko , Johannes Weiner , Zi Yan , Axel Rasmussen , Yuanchu Xie , Roman Gushchin , peterz@infradead.org, dave.hansen@linux.intel.com, mingo@redhat.com, tglx@linutronix.de, akpm@linux-foundation.org, david@redhat.com, derkling@google.com, junaids@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, reijiw@google.com, rientjes@google.com, rppt@kernel.org, vbabka@suse.cz, x86@kernel.org, yosry.ahmed@linux.dev Subject: Re: [PATCH 03/21] x86/mm: factor out phys_pgd_init() Message-ID: <20251025114801.GWaPy48dhlZ_EVoqKi@fat_crate.local> References: <20250924-b4-asi-page-alloc-v1-0-2d861768041f@google.com> <20250924-b4-asi-page-alloc-v1-3-2d861768041f@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250924-b4-asi-page-alloc-v1-3-2d861768041f@google.com> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: B8DCA14000C X-Stat-Signature: upfaixuc8k47hant1no9dioeoz451344 X-HE-Tag: 1761392926-861823 X-HE-Meta: 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 9vL5/crD mxKdK6kQN1Ez4WZIeRZCq8rOm9DMz6tofL+SJ4hwM/Qsy2spZmSM55pfIdgdInK1zkB1fxX/3mQKBEoRp224kjNaDeQ4SD/W6q9eo6IX70Ac7FnrJNeNn9ZLaiyt97W32bo0Nf3g2Cpr4oTBe8sdYcqKJoufiblcBtFZOwyMFT3bB7wOaceY12nSFHCDxh7b5Q/7TmFku7FG8j16d2nl5YqU68+GHF8ZTeqnusdetlnhpSUf5JpM88IFUfH9K4swBFtVsQmed0GO9eamnKGPRowvy2VmcEsaPDh1UXOe2ShKL/Ovunl2MEuHvMQ== 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 Wed, Sep 24, 2025 at 02:59:38PM +0000, Brendan Jackman wrote: > +static unsigned long __meminit > +__kernel_physical_mapping_init(unsigned long paddr_start, > + unsigned long paddr_end, > + unsigned long page_size_mask, > + pgprot_t prot, bool init) > +{ > + bool pgd_changed; I have to say, that pgd_changed is yuck but I don't have a better idea and this has happened a long time ago anyway. How about you have the caller pass in false: bool pgd_changed = false; and then callee sets it to true when it does so? > + unsigned long paddr_last; The tip-tree preferred ordering of variable declarations at the beginning of a function is reverse fir tree order:: struct long_struct_name *descriptive_name; unsigned long foo, bar; unsigned int tmp; int ret; The above is faster to parse than the reverse ordering:: int ret; unsigned int tmp; unsigned long foo, bar; struct long_struct_name *descriptive_name; And even more so than random ordering:: unsigned long foo, bar; int ret; struct long_struct_name *descriptive_name; unsigned int tmp; > + > + paddr_last = phys_pgd_init(init_mm.pgd, paddr_start, paddr_end, page_size_mask, > + prot, init, &pgd_changed); > + if (pgd_changed) > + sync_global_pgds((unsigned long)__va(paddr_start), > + (unsigned long)__va(paddr_end) - 1); > + > + return paddr_last; > +} > > /* > * Create page table mapping for the physical memory for specific physical > > -- > 2.50.1 > -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette