Hi Logan, Logan Gunthorpe <log...@deltatee.com> 於 2019年8月12日 週一 下午11:52寫道: > > > > On 2019-08-11 10:01 p.m., Greentime Hu wrote: > > Hi Logan, > > > > Logan Gunthorpe <log...@deltatee.com> 於 2019年8月10日 週六 上午3:03寫道: > >> > >> > >> > >> On 2019-08-09 11:01 a.m., Greentime Hu wrote: > >>> Hi Logan, > >>> > >>> Logan Gunthorpe <log...@deltatee.com> 於 2019年8月9日 週五 下午11:47寫道: > >>>> > >>>> > >>>> > >>>> On 2019-08-08 10:23 p.m., Greentime Hu wrote: > >>>>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > >>>>> index 3f12b069af1d..208b3e14ccd8 100644 > >>>>> --- a/arch/riscv/Kconfig > >>>>> +++ b/arch/riscv/Kconfig > >>>>> @@ -116,7 +116,8 @@ config PGTABLE_LEVELS > >>>>> default 2 > >>>>> > >>>>> config HAVE_ARCH_PFN_VALID > >>>>> - def_bool y > >>>>> + bool > >>>>> + default !SPARSEMEM_VMEMMAP > >>>>> > >>>>> menu "Platform type" > >>>>> > >>>>> diff --git a/arch/riscv/include/asm/page.h > >>>>> b/arch/riscv/include/asm/page.h > >>>>> index 8ddb6c7fedac..6991f7a5a4a7 100644 > >>>>> --- a/arch/riscv/include/asm/page.h > >>>>> +++ b/arch/riscv/include/asm/page.h > >>>>> @@ -93,16 +93,20 @@ extern unsigned long min_low_pfn; > >>>>> #define virt_to_pfn(vaddr) (phys_to_pfn(__pa(vaddr))) > >>>>> #define pfn_to_virt(pfn) (__va(pfn_to_phys(pfn))) > >>>>> > >>>>> +#if !defined(CONFIG_SPARSEMEM_VMEMMAP) > >>>>> +#define pfn_valid(pfn) \ > >>>>> + (((pfn) >= pfn_base) && (((pfn)-pfn_base) < max_mapnr)) > >>>>> #define virt_to_page(vaddr) (pfn_to_page(virt_to_pfn(vaddr))) > >>>>> #define page_to_virt(page) (pfn_to_virt(page_to_pfn(page))) > >>>>> +#else > >>>>> +#define virt_to_page(vaddr) ((struct page *)((((u64)vaddr - > >>>>> va_pa_offset) / PAGE_SIZE) * sizeof(struct page) + VMEMMAP_START)) > >>>>> +#define page_to_virt(pg) ((void *)(((((u64)pg - VMEMMAP_START) / > >>>>> sizeof(struct page)) * PAGE_SIZE) + va_pa_offset)) > >>>>> +#endif > >>>> > >>>> This doesn't make sense to me at all. It should always use pfn_to_page() > >>>> for virt_to_page() and the generic pfn_to_page()/page_to_pfn() > >>>> implementations essentially already do what you are doing in a cleaner > >>>> way. So I'd be really surprised if this does anything at all. > >>>> > >>> > >>> Thank you for point me out that. I just checked the generic > >>> implementation and I should use that one. > >>> Sorry I didn't check the generic one and just implement it again. > >>> I think the only patch we need is the first part to use generic > >>> pfn_valid(). I just tested it and yes it can boot successfully in dts > >>> with hole. > >>> > >>> It will fail in this check ((pfn)-pfn_base) < max_mapnr. > >> > >> Sounds to me like max_mapnr is not set correctly. See the code in > >> setup_bootmem(). Seems like 'mem_size' should be set to the largest > >> memory block, not just the one that contains the kernel... > >> > >> > >>> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > >>> index 3f12b069af1d..208b3e14ccd8 100644 > >>> --- a/arch/riscv/Kconfig > >>> +++ b/arch/riscv/Kconfig > >>> @@ -116,7 +116,8 @@ config PGTABLE_LEVELS > >>> default 2 > >>> > >>> config HAVE_ARCH_PFN_VALID > >>> - def_bool y > >>> + bool > >>> + default !SPARSEMEM_VMEMMAP > >>> > >>> menu "Platform type" > >>> > >>> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h > >>> index 8ddb6c7fedac..80d28fa1e2eb 100644 > >>> --- a/arch/riscv/include/asm/page.h > >>> +++ b/arch/riscv/include/asm/page.h > >>> @@ -100,8 +100,10 @@ extern unsigned long min_low_pfn; > >>> #define page_to_bus(page) (page_to_phys(page)) > >>> #define phys_to_page(paddr) (pfn_to_page(phys_to_pfn(paddr))) > >>> > >>> +#if !defined(CONFIG_SPARSEMEM_VMEMMAP) > >>> #define pfn_valid(pfn) \ > >>> (((pfn) >= pfn_base) && (((pfn)-pfn_base) < max_mapnr)) > >>> +#endif > >>> > >>> #define ARCH_PFN_OFFSET (pfn_base) > >> > >> > >> This patch still makes no sense. I'm not sure why we have an arch > >> specific pfn_valid() because it's very similar to the generic one. But > >> my guess is there's a reason for it and it's not doing what it is > >> supposed when you remove it for the sparsemem case. > > > > It will use another pfn_valid() implementation in > > include/linux/mmzone.h if CONFIG_SPARSEMEM and > > !CONFIG_HAVE_ARCH_PFN_VALID > > It will be this one. > > > > static inline int pfn_valid(unsigned long pfn) > > { > > if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS) > > return 0; > > return valid_section(__nr_to_section(pfn_to_section_nr(pfn))); > > } > > Ah, ok I see. "page.h" is only included in no-mmu arches. Which explains > why riscv re-implements that macro. Couple follow up questions then: > > * Did you test the memory-with-hole scenario without the sparsemem > patches? It seems pfn_valid() will be wrong regardless of sparse/flat mem. > > * Any chance we can just use the generic pfn_valid() function in all > cases not just sparsemem? Can you test that? >
I think flat mem doesn't support memory-with-hole scenario. In mm/Kconfig, it says " For systems that have holes in their physical address spaces and for features like NUMA and memory hotplug, choose "Sparse Memory" " IMHO, the memory-with-hole scenario should only be tested for sparse mem but flat mem. The generic pfn_valid() is just for non-mmu arches. Every architecture with mmu defines their own pfn_valid(). This is supposed to be another separate patch that do we need to implement a generic pfn_valid().