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From: Mike Rapoport <rppt@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
	Ard Biesheuvel <ardb@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Anshuman Khandual <anshuman.khandual@arm.com>,
	Will Deacon <will@kernel.org>
Subject: Re: [PATCH] arm64: Force SPARSEMEM_VMEMMAP as the only memory management model
Date: Thu, 22 Apr 2021 13:08:06 +0300	[thread overview]
Message-ID: <YIFLBkFiY7xzKxHS@kernel.org> (raw)
In-Reply-To: <20210420093559.23168-1-catalin.marinas@arm.com>

On Tue, Apr 20, 2021 at 10:35:59AM +0100, 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@arm.com>
> Cc: Will Deacon <will@kernel.org>

Acked-by: Mike Rapoport <rppt@linux.ibm.com>

> ---
> 
> 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)
>  #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 },
>  };
>  
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

-- 
Sincerely yours,
Mike.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
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  parent reply	other threads:[~2021-04-22 10:10 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-20  9:35 [PATCH] arm64: Force SPARSEMEM_VMEMMAP as the only memory management model Catalin Marinas
2021-04-20 10:19 ` Will Deacon
2021-04-20 10:28   ` Ard Biesheuvel
2021-04-20 10:47 ` Marc Zyngier
2021-04-21  4:48 ` Anshuman Khandual
2021-04-21 13:02   ` Catalin Marinas
2021-04-22  3:04     ` Anshuman Khandual
2021-04-22 10:08 ` Mike Rapoport [this message]
2021-04-23 17:09 ` Catalin Marinas

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