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Miller" , Dave Hansen , David Hildenbrand , Dinh Nguyen , Geert Uytterhoeven , Guo Ren , Heiko Carstens , Helge Deller , Huacai Chen , Ingo Molnar , Johannes Berg , John Paul Adrian Glaubitz , Jonathan Corbet , "Liam R. Howlett" , Lorenzo Stoakes , Magnus Lindholm , Matt Turner , Max Filippov , Michael Ellerman , Michal Hocko , Michal Simek , Mike Rapoport , Muchun Song , Oscar Salvador , Palmer Dabbelt , Pratyush Yadav , Richard Weinberger , Russell King , Stafford Horne , Suren Baghdasaryan , Thomas Bogendoerfer , Thomas Gleixner , Vasily Gorbik , Vineet Gupta , Vlastimil Babka , Will Deacon , x86@kernel.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, linux-cxl@vger.kernel.org, linux-doc@vger.kernel.org, linux-hexagon@vger.kernel.org, linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-openrisc@vger.kernel.org, linux-parisc@vger.kernel.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, linux-snps-arc@lists.infradead.org, linux-um@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, loongarch@lists.linux.dev, sparclinux@vger.kernel.org Subject: Re: [PATCH v2 14/28] powerpc: introduce arch_zone_limits_init() In-Reply-To: <20260102070005.65328-15-rppt@kernel.org> Date: Wed, 07 Jan 2026 09:57:34 +0530 Message-ID: <87ldia9he1.ritesh.list@gmail.com> References: <20260102070005.65328-1-rppt@kernel.org> <20260102070005.65328-15-rppt@kernel.org> Precedence: bulk X-Mailing-List: linux-alpha@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Mike Rapoport writes: > From: "Mike Rapoport (Microsoft)" > > Move calculations of zone limits to a dedicated arch_zone_limits_init() > function. > > Later MM core will use this function as an architecture specific callback > during nodes and zones initialization and thus there won't be a need to > call free_area_init() from every architecture. > > Signed-off-by: Mike Rapoport (Microsoft) > --- > arch/powerpc/mm/mem.c | 22 ++++++++++++---------- > 1 file changed, 12 insertions(+), 10 deletions(-) > > diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c > index 3ddbfdbfa941..32c496bfab4f 100644 > --- a/arch/powerpc/mm/mem.c > +++ b/arch/powerpc/mm/mem.c > @@ -221,13 +221,23 @@ static int __init mark_nonram_nosave(void) > * anyway) will take a first dip into ZONE_NORMAL and get otherwise served by > * ZONE_DMA. > */ > -static unsigned long max_zone_pfns[MAX_NR_ZONES]; > +void __init arch_zone_limits_init(unsigned long *max_zone_pfns) > +{ > +#ifdef CONFIG_ZONE_DMA > + max_zone_pfns[ZONE_DMA] = min(zone_dma_limit, max_low_pfn - 1) + 1; Hi Mike, This doesn't look correct. Isn't the zone_dma_limit value in bytes actually? Shouldn't it be - max_zone_pfns[ZONE_DMA] = min((zone_dma_limit >> PAGE_SHIFT) + 1, max_low_pfn); -ritesh > +#endif > + max_zone_pfns[ZONE_NORMAL] = max_low_pfn; > +#ifdef CONFIG_HIGHMEM > + max_zone_pfns[ZONE_HIGHMEM] = max_pfn; > +#endif > +} > > /* > * paging_init() sets up the page tables - in fact we've already done this. > */ > void __init paging_init(void) > { > + unsigned long max_zone_pfns[MAX_NR_ZONES]; > unsigned long long total_ram = memblock_phys_mem_size(); > phys_addr_t top_of_ram = memblock_end_of_DRAM(); > int zone_dma_bits; > @@ -259,15 +269,7 @@ void __init paging_init(void) > > zone_dma_limit = DMA_BIT_MASK(zone_dma_bits); > > -#ifdef CONFIG_ZONE_DMA > - max_zone_pfns[ZONE_DMA] = min(max_low_pfn, > - 1UL << (zone_dma_bits - PAGE_SHIFT)); > -#endif > - max_zone_pfns[ZONE_NORMAL] = max_low_pfn; > -#ifdef CONFIG_HIGHMEM > - max_zone_pfns[ZONE_HIGHMEM] = max_pfn; > -#endif > - > + arch_zone_limits_init(max_zone_pfns); > free_area_init(max_zone_pfns); > > mark_nonram_nosave(); > -- > 2.51.0