From: Mike Rapoport <rppt@xxxxxxxxxxxxx> Subject: mm: free_area_init: allow defining max_zone_pfn in descending order Some architectures (e.g. ARC) have the ZONE_HIGHMEM zone below the ZONE_NORMAL. Allowing free_area_init() parse max_zone_pfn array even it is sorted in descending order allows using free_area_init() on such architectures. Add top -> down traversal of max_zone_pfn array in free_area_init() and use the latter in ARC node/zone initialization. [rppt@xxxxxxxxxx: ARC fix] Link: http://lkml.kernel.org/r/20200504153901.GM14260@xxxxxxxxxx [rppt@xxxxxxxxxxxxx: arc: free_area_init(): take into account PAE40 mode] Link: http://lkml.kernel.org/r/20200507205900.GH683243@xxxxxxxxxxxxx [akpm@xxxxxxxxxxxxxxxxxxxx: declare arch_has_descending_max_zone_pfns()] Link: http://lkml.kernel.org/r/20200412194859.12663-18-rppt@xxxxxxxxxx Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx> Reviewed-by: Baoquan He <bhe@xxxxxxxxxx> Tested-by: Hoan Tran <hoan@xxxxxxxxxxxxxxxxxxxxxx> [arm64] Cc: Brian Cain <bcain@xxxxxxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Cc: Greentime Hu <green.hu@xxxxxxxxx> Cc: Greg Ungerer <gerg@xxxxxxxxxxxxxx> Cc: Guan Xuetao <gxt@xxxxxxxxxx> Cc: Guo Ren <guoren@xxxxxxxxxx> Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> Cc: Helge Deller <deller@xxxxxx> Cc: "James E.J. Bottomley" <James.Bottomley@xxxxxxxxxxxxxxxxxxxxx> Cc: Jonathan Corbet <corbet@xxxxxxx> Cc: Ley Foon Tan <ley.foon.tan@xxxxxxxxx> Cc: Mark Salter <msalter@xxxxxxxxxx> Cc: Matt Turner <mattst88@xxxxxxxxx> Cc: Max Filippov <jcmvbkbc@xxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Michal Simek <monstr@xxxxxxxxx> Cc: Nick Hu <nickhu@xxxxxxxxxxxxx> Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx> Cc: Richard Weinberger <richard@xxxxxx> Cc: Rich Felker <dalias@xxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: Stafford Horne <shorne@xxxxxxxxx> Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx> Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx> Cc: Guenter Roeck <linux@xxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/arc/mm/init.c | 41 ++++++++++++----------------------------- include/linux/mm.h | 1 + mm/page_alloc.c | 26 +++++++++++++++++++++----- 3 files changed, 34 insertions(+), 34 deletions(-) --- a/arch/arc/mm/init.c~mm-free_area_init-allow-defining-max_zone_pfn-in-descending-order +++ a/arch/arc/mm/init.c @@ -63,11 +63,13 @@ void __init early_init_dt_add_memory_arc low_mem_sz = size; in_use = 1; + memblock_add_node(base, size, 0); } else { #ifdef CONFIG_HIGHMEM high_mem_start = base; high_mem_sz = size; in_use = 1; + memblock_add_node(base, size, 1); #endif } @@ -75,6 +77,11 @@ void __init early_init_dt_add_memory_arc base, TO_MB(size), !in_use ? "Not used":""); } +bool arch_has_descending_max_zone_pfns(void) +{ + return !IS_ENABLED(CONFIG_ARC_HAS_PAE40); +} + /* * First memory setup routine called from setup_arch() * 1. setup swapper's mm @init_mm @@ -83,8 +90,7 @@ void __init early_init_dt_add_memory_arc */ void __init setup_arch_memory(void) { - unsigned long zones_size[MAX_NR_ZONES]; - unsigned long zones_holes[MAX_NR_ZONES]; + unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; init_mm.start_code = (unsigned long)_text; init_mm.end_code = (unsigned long)_etext; @@ -115,7 +121,6 @@ void __init setup_arch_memory(void) * the crash */ - memblock_add_node(low_mem_start, low_mem_sz, 0); memblock_reserve(CONFIG_LINUX_LINK_BASE, __pa(_end) - CONFIG_LINUX_LINK_BASE); @@ -133,22 +138,7 @@ void __init setup_arch_memory(void) memblock_dump_all(); /*----------------- node/zones setup --------------------------*/ - memset(zones_size, 0, sizeof(zones_size)); - memset(zones_holes, 0, sizeof(zones_holes)); - - zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn; - zones_holes[ZONE_NORMAL] = 0; - - /* - * We can't use the helper free_area_init(zones[]) because it uses - * PAGE_OFFSET to compute the @min_low_pfn which would be wrong - * when our kernel doesn't start at PAGE_OFFSET, i.e. - * PAGE_OFFSET != CONFIG_LINUX_RAM_BASE - */ - free_area_init_node(0, /* node-id */ - zones_size, /* num pages per zone */ - min_low_pfn, /* first pfn of node */ - zones_holes); /* holes */ + max_zone_pfn[ZONE_NORMAL] = max_low_pfn; #ifdef CONFIG_HIGHMEM /* @@ -168,20 +158,13 @@ void __init setup_arch_memory(void) min_high_pfn = PFN_DOWN(high_mem_start); max_high_pfn = PFN_DOWN(high_mem_start + high_mem_sz); - zones_size[ZONE_NORMAL] = 0; - zones_holes[ZONE_NORMAL] = 0; - - zones_size[ZONE_HIGHMEM] = max_high_pfn - min_high_pfn; - zones_holes[ZONE_HIGHMEM] = 0; - - free_area_init_node(1, /* node-id */ - zones_size, /* num pages per zone */ - min_high_pfn, /* first pfn of node */ - zones_holes); /* holes */ + max_zone_pfn[ZONE_HIGHMEM] = max_high_pfn; high_memory = (void *)(min_high_pfn << PAGE_SHIFT); kmap_init(); #endif + + free_area_init(max_zone_pfn); } /* --- a/include/linux/mm.h~mm-free_area_init-allow-defining-max_zone_pfn-in-descending-order +++ a/include/linux/mm.h @@ -2473,6 +2473,7 @@ extern void setup_per_cpu_pageset(void); extern int min_free_kbytes; extern int watermark_boost_factor; extern int watermark_scale_factor; +extern bool arch_has_descending_max_zone_pfns(void); /* nommu.c */ extern atomic_long_t mmap_pages_allocated; --- a/mm/page_alloc.c~mm-free_area_init-allow-defining-max_zone_pfn-in-descending-order +++ a/mm/page_alloc.c @@ -7408,6 +7408,15 @@ static void check_for_memory(pg_data_t * } } +/* + * Some architecturs, e.g. ARC may have ZONE_HIGHMEM below ZONE_NORMAL. For + * such cases we allow max_zone_pfn sorted in the descending order + */ +bool __weak arch_has_descending_max_zone_pfns(void) +{ + return false; +} + /** * free_area_init - Initialise all pg_data_t and zone data * @max_zone_pfn: an array of max PFNs for each zone @@ -7424,7 +7433,8 @@ static void check_for_memory(pg_data_t * void __init free_area_init(unsigned long *max_zone_pfn) { unsigned long start_pfn, end_pfn; - int i, nid; + int i, nid, zone; + bool descending; /* Record where the zone boundaries are */ memset(arch_zone_lowest_possible_pfn, 0, @@ -7433,14 +7443,20 @@ void __init free_area_init(unsigned long sizeof(arch_zone_highest_possible_pfn)); start_pfn = find_min_pfn_with_active_regions(); + descending = arch_has_descending_max_zone_pfns(); for (i = 0; i < MAX_NR_ZONES; i++) { - if (i == ZONE_MOVABLE) + if (descending) + zone = MAX_NR_ZONES - i - 1; + else + zone = i; + + if (zone == ZONE_MOVABLE) continue; - end_pfn = max(max_zone_pfn[i], start_pfn); - arch_zone_lowest_possible_pfn[i] = start_pfn; - arch_zone_highest_possible_pfn[i] = end_pfn; + end_pfn = max(max_zone_pfn[zone], start_pfn); + arch_zone_lowest_possible_pfn[zone] = start_pfn; + arch_zone_highest_possible_pfn[zone] = end_pfn; start_pfn = end_pfn; } _
