[PATCH] arm64: Force SPARSEMEM_VMEMMAP as the only memory management model
Anshuman Khandual
anshuman.khandual at arm.com
Wed Apr 21 05:48:56 BST 2021
On 4/20/21 3:05 PM, Catalin Marinas wrote:
> Currently arm64 allows a choice of FLATMEM, SPARSEMEM and
> SPARSEMEM_VMEMMAP. However, only the latter is tested regularly. FLATMEM
> does not seem to boot in certain configurations (guest under KVM with
> Qemu as a VMM). Since the reduction of the SECTION_SIZE_BITS to 27 (4K
> pages) or 29 (64K page), there's little argument against the memory
> wasted by the mem_map array with SPARSEMEM.
>
> Make SPARSEMEM_VMEMMAP the only available option, non-selectable, and
> remove the corresponding #ifdefs under arch/arm64/.
>
> Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Will Deacon <will at kernel.org>
> ---
>
> If there are any concerns, please shout (but show numbers as well to
> back it up).
>
> arch/arm64/Kconfig | 10 +---------
> arch/arm64/include/asm/kernel-pgtable.h | 2 +-
> arch/arm64/include/asm/memory.h | 4 ++--
> arch/arm64/include/asm/sparsemem.h | 3 ---
> arch/arm64/mm/init.c | 8 ++------
> arch/arm64/mm/mmu.c | 2 --
> arch/arm64/mm/ptdump.c | 2 --
> 7 files changed, 6 insertions(+), 25 deletions(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 9b4d629f7628..01c294035928 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1040,15 +1040,7 @@ source "kernel/Kconfig.hz"
> config ARCH_SPARSEMEM_ENABLE
> def_bool y
> select SPARSEMEM_VMEMMAP_ENABLE
> -
> -config ARCH_SPARSEMEM_DEFAULT
> - def_bool ARCH_SPARSEMEM_ENABLE
> -
> -config ARCH_SELECT_MEMORY_MODEL
> - def_bool ARCH_SPARSEMEM_ENABLE
> -
> -config ARCH_FLATMEM_ENABLE
> - def_bool !NUMA
> + select SPARSEMEM_VMEMMAP
>
> config HW_PERF_EVENTS
> def_bool y
> diff --git a/arch/arm64/include/asm/kernel-pgtable.h b/arch/arm64/include/asm/kernel-pgtable.h
> index 587c504a4c8b..d44df9d62fc9 100644
> --- a/arch/arm64/include/asm/kernel-pgtable.h
> +++ b/arch/arm64/include/asm/kernel-pgtable.h
> @@ -136,7 +136,7 @@
> * has a direct correspondence, and needs to appear sufficiently aligned
> * in the virtual address space.
> */
> -#if defined(CONFIG_SPARSEMEM_VMEMMAP) && ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS
> +#if ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS
> #define ARM64_MEMSTART_ALIGN (1UL << SECTION_SIZE_BITS)
> #else
> #define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT)
> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
> index b943879c1c24..15018dc59554 100644
> --- a/arch/arm64/include/asm/memory.h
> +++ b/arch/arm64/include/asm/memory.h
> @@ -329,7 +329,7 @@ static inline void *phys_to_virt(phys_addr_t x)
> */
> #define ARCH_PFN_OFFSET ((unsigned long)PHYS_PFN_OFFSET)
>
> -#if !defined(CONFIG_SPARSEMEM_VMEMMAP) || defined(CONFIG_DEBUG_VIRTUAL)
> +#if defined(CONFIG_DEBUG_VIRTUAL)
A small nit. Should this be #ifdef CONFIG_DEBUG_VIRTUAL instead ? This is
an user selectable config and the conditional check here does not have an
#elseif part either. But then there are similar such instances else where
on arm64 platform as well.
> #define page_to_virt(x) ({ \
> __typeof__(x) __page = x; \
> void *__addr = __va(page_to_phys(__page)); \
> @@ -349,7 +349,7 @@ static inline void *phys_to_virt(phys_addr_t x)
> u64 __addr = VMEMMAP_START + (__idx * sizeof(struct page)); \
> (struct page *)__addr; \
> })
> -#endif /* !CONFIG_SPARSEMEM_VMEMMAP || CONFIG_DEBUG_VIRTUAL */
> +#endif /* CONFIG_DEBUG_VIRTUAL */
>
> #define virt_addr_valid(addr) ({ \
> __typeof__(addr) __addr = __tag_reset(addr); \
> diff --git a/arch/arm64/include/asm/sparsemem.h b/arch/arm64/include/asm/sparsemem.h
> index eb4a75d720ed..4b73463423c3 100644
> --- a/arch/arm64/include/asm/sparsemem.h
> +++ b/arch/arm64/include/asm/sparsemem.h
> @@ -5,7 +5,6 @@
> #ifndef __ASM_SPARSEMEM_H
> #define __ASM_SPARSEMEM_H
>
> -#ifdef CONFIG_SPARSEMEM
> #define MAX_PHYSMEM_BITS CONFIG_ARM64_PA_BITS
>
> /*
> @@ -27,6 +26,4 @@
> #define SECTION_SIZE_BITS 27
> #endif /* CONFIG_ARM64_64K_PAGES */
>
> -#endif /* CONFIG_SPARSEMEM*/
> -
> #endif
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 3685e12aba9b..a205538aa1d5 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -220,6 +220,7 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
> int pfn_valid(unsigned long pfn)
> {
> phys_addr_t addr = PFN_PHYS(pfn);
> + struct mem_section *ms;
>
> /*
> * Ensure the upper PAGE_SHIFT bits are clear in the
> @@ -230,10 +231,6 @@ int pfn_valid(unsigned long pfn)
> if (PHYS_PFN(addr) != pfn)
> return 0;
>
> -#ifdef CONFIG_SPARSEMEM
> -{
> - struct mem_section *ms;
> -
> if (pfn_to_section_nr(pfn) >= NR_MEM_SECTIONS)
> return 0;
>
> @@ -252,8 +249,7 @@ int pfn_valid(unsigned long pfn)
> */
> if (!early_section(ms))
> return pfn_section_valid(ms, pfn);
> -}
> -#endif
> +
> return memblock_is_map_memory(addr);
> }
> EXPORT_SYMBOL(pfn_valid);
> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
> index fac957ff5187..af0ebcad3e1f 100644
> --- a/arch/arm64/mm/mmu.c
> +++ b/arch/arm64/mm/mmu.c
> @@ -1113,7 +1113,6 @@ static void free_empty_tables(unsigned long addr, unsigned long end,
> }
> #endif
>
> -#ifdef CONFIG_SPARSEMEM_VMEMMAP
> #if !ARM64_SWAPPER_USES_SECTION_MAPS
> int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node,
> struct vmem_altmap *altmap)
> @@ -1177,7 +1176,6 @@ void vmemmap_free(unsigned long start, unsigned long end,
> free_empty_tables(start, end, VMEMMAP_START, VMEMMAP_END);
> #endif
> }
> -#endif /* CONFIG_SPARSEMEM_VMEMMAP */
>
> static inline pud_t *fixmap_pud(unsigned long addr)
> {
> diff --git a/arch/arm64/mm/ptdump.c b/arch/arm64/mm/ptdump.c
> index a50e92ea1878..a1937dfff31c 100644
> --- a/arch/arm64/mm/ptdump.c
> +++ b/arch/arm64/mm/ptdump.c
> @@ -51,10 +51,8 @@ static struct addr_marker address_markers[] = {
> { FIXADDR_TOP, "Fixmap end" },
> { PCI_IO_START, "PCI I/O start" },
> { PCI_IO_END, "PCI I/O end" },
> -#ifdef CONFIG_SPARSEMEM_VMEMMAP
> { VMEMMAP_START, "vmemmap start" },
> { VMEMMAP_START + VMEMMAP_SIZE, "vmemmap end" },
> -#endif
> { -1, NULL },
> };
>
>
Reviewed-by: Anshuman Khandual <anshuman.khandual at arm.com>
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