From: Mike Rapoport <rppt@xxxxxxxxxxxxx> Subject: arm: remove CONFIG_ARCH_HAS_HOLES_MEMORYMODEL ARM is the only architecture that defines CONFIG_ARCH_HAS_HOLES_MEMORYMODEL which in turn enables memmap_valid_within() function that is intended to verify existence of struct page associated with a pfn when there are holes in the memory map. However, the ARCH_HAS_HOLES_MEMORYMODEL also enables HAVE_ARCH_PFN_VALID and arch-specific pfn_valid() implementation that also deals with the holes in the memory map. The only two users of memmap_valid_within() call this function after a call to pfn_valid() so the memmap_valid_within() check becomes redundant. Remove CONFIG_ARCH_HAS_HOLES_MEMORYMODEL and memmap_valid_within() and rely entirely on ARM's implementation of pfn_valid() that is now enabled unconditionally. Link: https://lkml.kernel.org/r/20201101170454.9567-9-rppt@xxxxxxxxxx Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Greg Ungerer <gerg@xxxxxxxxxxxxxx> Cc: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Matt Turner <mattst88@xxxxxxxxx> Cc: Meelis Roos <mroos@xxxxxxxx> Cc: Michael Schmitz <schmitzmic@xxxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/vm/memory-model.rst | 3 -- arch/arm/Kconfig | 8 +------ arch/arm/mach-bcm/Kconfig | 1 arch/arm/mach-davinci/Kconfig | 1 arch/arm/mach-exynos/Kconfig | 1 arch/arm/mach-highbank/Kconfig | 1 arch/arm/mach-omap2/Kconfig | 1 arch/arm/mach-s5pv210/Kconfig | 1 arch/arm/mach-tango/Kconfig | 1 fs/proc/kcore.c | 2 - include/linux/mmzone.h | 31 ---------------------------- mm/mmzone.c | 14 ------------ mm/vmstat.c | 4 --- 13 files changed, 3 insertions(+), 66 deletions(-) --- a/arch/arm/Kconfig~arm-remove-config_arch_has_holes_memorymodel +++ a/arch/arm/Kconfig @@ -25,7 +25,7 @@ config ARM select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAVE_CUSTOM_GPIO_H select ARCH_HAS_GCOV_PROFILE_ALL - select ARCH_KEEP_MEMBLOCK if HAVE_ARCH_PFN_VALID || KEXEC + select ARCH_KEEP_MEMBLOCK select ARCH_MIGHT_HAVE_PC_PARPORT select ARCH_NO_SG_CHAIN if !ARM_HAS_SG_CHAIN select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX @@ -520,7 +520,6 @@ config ARCH_S3C24XX config ARCH_OMAP1 bool "TI OMAP1" depends on MMU - select ARCH_HAS_HOLES_MEMORYMODEL select ARCH_OMAP select CLKDEV_LOOKUP select CLKSRC_MMIO @@ -1480,9 +1479,6 @@ config OABI_COMPAT UNPREDICTABLE (in fact it can be predicted that it won't work at all). If in doubt say N. -config ARCH_HAS_HOLES_MEMORYMODEL - bool - config ARCH_SELECT_MEMORY_MODEL bool @@ -1494,7 +1490,7 @@ config ARCH_SPARSEMEM_ENABLE select SPARSEMEM_STATIC if SPARSEMEM config HAVE_ARCH_PFN_VALID - def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM + def_bool y config HIGHMEM bool "High Memory Support" --- a/arch/arm/mach-bcm/Kconfig~arm-remove-config_arch_has_holes_memorymodel +++ a/arch/arm/mach-bcm/Kconfig @@ -211,7 +211,6 @@ config ARCH_BRCMSTB select BCM7038_L1_IRQ select BRCMSTB_L2_IRQ select BCM7120_L2_IRQ - select ARCH_HAS_HOLES_MEMORYMODEL select ZONE_DMA if ARM_LPAE select SOC_BRCMSTB select SOC_BUS --- a/arch/arm/mach-davinci/Kconfig~arm-remove-config_arch_has_holes_memorymodel +++ a/arch/arm/mach-davinci/Kconfig @@ -5,7 +5,6 @@ menuconfig ARCH_DAVINCI depends on ARCH_MULTI_V5 select DAVINCI_TIMER select ZONE_DMA - select ARCH_HAS_HOLES_MEMORYMODEL select PM_GENERIC_DOMAINS if PM select PM_GENERIC_DOMAINS_OF if PM && OF select REGMAP_MMIO --- a/arch/arm/mach-exynos/Kconfig~arm-remove-config_arch_has_holes_memorymodel +++ a/arch/arm/mach-exynos/Kconfig @@ -8,7 +8,6 @@ menuconfig ARCH_EXYNOS bool "Samsung Exynos" depends on ARCH_MULTI_V7 - select ARCH_HAS_HOLES_MEMORYMODEL select ARCH_SUPPORTS_BIG_ENDIAN select ARM_AMBA select ARM_GIC --- a/arch/arm/mach-highbank/Kconfig~arm-remove-config_arch_has_holes_memorymodel +++ a/arch/arm/mach-highbank/Kconfig @@ -2,7 +2,6 @@ config ARCH_HIGHBANK bool "Calxeda ECX-1000/2000 (Highbank/Midway)" depends on ARCH_MULTI_V7 - select ARCH_HAS_HOLES_MEMORYMODEL select ARCH_SUPPORTS_BIG_ENDIAN select ARM_AMBA select ARM_ERRATA_764369 if SMP --- a/arch/arm/mach-omap2/Kconfig~arm-remove-config_arch_has_holes_memorymodel +++ a/arch/arm/mach-omap2/Kconfig @@ -93,7 +93,6 @@ config SOC_DRA7XX config ARCH_OMAP2PLUS bool select ARCH_HAS_BANDGAP - select ARCH_HAS_HOLES_MEMORYMODEL select ARCH_HAS_RESET_CONTROLLER select ARCH_OMAP select CLKSRC_MMIO --- a/arch/arm/mach-s5pv210/Kconfig~arm-remove-config_arch_has_holes_memorymodel +++ a/arch/arm/mach-s5pv210/Kconfig @@ -8,7 +8,6 @@ config ARCH_S5PV210 bool "Samsung S5PV210/S5PC110" depends on ARCH_MULTI_V7 - select ARCH_HAS_HOLES_MEMORYMODEL select ARM_VIC select CLKSRC_SAMSUNG_PWM select COMMON_CLK_SAMSUNG --- a/arch/arm/mach-tango/Kconfig~arm-remove-config_arch_has_holes_memorymodel +++ a/arch/arm/mach-tango/Kconfig @@ -3,7 +3,6 @@ config ARCH_TANGO bool "Sigma Designs Tango4 (SMP87xx)" depends on ARCH_MULTI_V7 # Cortex-A9 MPCore r3p0, PL310 r3p2 - select ARCH_HAS_HOLES_MEMORYMODEL select ARM_ERRATA_754322 select ARM_ERRATA_764369 if SMP select ARM_ERRATA_775420 --- a/Documentation/vm/memory-model.rst~arm-remove-config_arch_has_holes_memorymodel +++ a/Documentation/vm/memory-model.rst @@ -51,8 +51,7 @@ call :c:func:`free_area_init` function. usable until the call to :c:func:`memblock_free_all` that hands all the memory to the page allocator. -If an architecture enables `CONFIG_ARCH_HAS_HOLES_MEMORYMODEL` option, -it may free parts of the `mem_map` array that do not cover the +An architecture may free parts of the `mem_map` array that do not cover the actual physical pages. In such case, the architecture specific :c:func:`pfn_valid` implementation should take the holes in the `mem_map` into account. --- a/fs/proc/kcore.c~arm-remove-config_arch_has_holes_memorymodel +++ a/fs/proc/kcore.c @@ -193,8 +193,6 @@ kclist_add_private(unsigned long pfn, un return 1; p = pfn_to_page(pfn); - if (!memmap_valid_within(pfn, p, page_zone(p))) - return 1; ent = kmalloc(sizeof(*ent), GFP_KERNEL); if (!ent) --- a/include/linux/mmzone.h~arm-remove-config_arch_has_holes_memorymodel +++ a/include/linux/mmzone.h @@ -1440,37 +1440,6 @@ void sparse_init(void); #define pfn_valid_within(pfn) (1) #endif -#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL -/* - * pfn_valid() is meant to be able to tell if a given PFN has valid memmap - * associated with it or not. This means that a struct page exists for this - * pfn. The caller cannot assume the page is fully initialized in general. - * Hotplugable pages might not have been onlined yet. pfn_to_online_page() - * will ensure the struct page is fully online and initialized. Special pages - * (e.g. ZONE_DEVICE) are never onlined and should be treated accordingly. - * - * In FLATMEM, it is expected that holes always have valid memmap as long as - * there is valid PFNs either side of the hole. In SPARSEMEM, it is assumed - * that a valid section has a memmap for the entire section. - * - * However, an ARM, and maybe other embedded architectures in the future - * free memmap backing holes to save memory on the assumption the memmap is - * never used. The page_zone linkages are then broken even though pfn_valid() - * returns true. A walker of the full memmap must then do this additional - * check to ensure the memmap they are looking at is sane by making sure - * the zone and PFN linkages are still valid. This is expensive, but walkers - * of the full memmap are extremely rare. - */ -bool memmap_valid_within(unsigned long pfn, - struct page *page, struct zone *zone); -#else -static inline bool memmap_valid_within(unsigned long pfn, - struct page *page, struct zone *zone) -{ - return true; -} -#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */ - #endif /* !__GENERATING_BOUNDS.H */ #endif /* !__ASSEMBLY__ */ #endif /* _LINUX_MMZONE_H */ --- a/mm/mmzone.c~arm-remove-config_arch_has_holes_memorymodel +++ a/mm/mmzone.c @@ -72,20 +72,6 @@ struct zoneref *__next_zones_zonelist(st return z; } -#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL -bool memmap_valid_within(unsigned long pfn, - struct page *page, struct zone *zone) -{ - if (page_to_pfn(page) != pfn) - return false; - - if (page_zone(page) != zone) - return false; - - return true; -} -#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */ - void lruvec_init(struct lruvec *lruvec) { enum lru_list lru; --- a/mm/vmstat.c~arm-remove-config_arch_has_holes_memorymodel +++ a/mm/vmstat.c @@ -1503,10 +1503,6 @@ static void pagetypeinfo_showblockcount_ if (!page) continue; - /* Watch for unexpected holes punched in the memmap */ - if (!memmap_valid_within(pfn, page, zone)) - continue; - if (page_zone(page) != zone) continue; _
