[PATCH v2 11/13] arch, mm: streamline HIGHMEM freeing
From: Mike Rapoport <rppt@kernel.org>
Date: 2025-03-13 13:52:50
Also in:
linux-alpha, linux-arch, linux-m68k, linux-mips, linux-mm, linux-riscv, linux-s390, linux-sh, linux-um, lkml, loongarch, sparclinux
Subsystem:
arm port, c-sky architecture, linux for powerpc (32-bit and 64-bit), memblock and memory management initialization, memory management, memory management - core, microblaze architecture, mips, sparc + ultrasparc (sparc/sparc64), synopsys arc architecture, tensilica xtensa port (xtensa), the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Russell King, Guo Ren, Madhavan Srinivasan, Michael Ellerman, Mike Rapoport, Andrew Morton, David Hildenbrand, Michal Simek, Thomas Bogendoerfer, "David S. Miller", Andreas Larsson, Vineet Gupta, Chris Zankel, Max Filippov, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski, Peter Zijlstra
From: "Mike Rapoport (Microsoft)" <rppt@kernel.org> All architectures that support HIGHMEM have their code that frees high memory pages to the buddy allocator while __free_memory_core() is limited to freeing only low memory. There is no actual reason for that. The memory map is completely ready by the time memblock_free_all() is called and high pages can be released to the buddy allocator along with low memory. Remove low memory limit from __free_memory_core() and drop per-architecture code that frees high memory pages. Acked-by: Dave Hansen <dave.hansen@linux.intel.com> # x86 Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> --- arch/arc/mm/init.c | 6 +----- arch/arm/mm/init.c | 29 ----------------------------- arch/csky/mm/init.c | 14 -------------- arch/microblaze/mm/init.c | 16 ---------------- arch/mips/mm/init.c | 20 -------------------- arch/powerpc/mm/mem.c | 14 -------------- arch/sparc/mm/init_32.c | 25 ------------------------- arch/x86/include/asm/highmem.h | 3 --- arch/x86/include/asm/numa.h | 4 ---- arch/x86/include/asm/numa_32.h | 13 ------------- arch/x86/mm/Makefile | 2 -- arch/x86/mm/highmem_32.c | 34 ---------------------------------- arch/x86/mm/init_32.c | 28 ---------------------------- arch/xtensa/mm/init.c | 29 ----------------------------- include/linux/mm.h | 1 - mm/memblock.c | 3 +-- 16 files changed, 2 insertions(+), 239 deletions(-) delete mode 100644 arch/x86/include/asm/numa_32.h delete mode 100644 arch/x86/mm/highmem_32.c
diff --git a/arch/arc/mm/init.c b/arch/arc/mm/init.c
index 05025122e965..11ce638731c9 100644
--- a/arch/arc/mm/init.c
+++ b/arch/arc/mm/init.c@@ -160,11 +160,7 @@ void __init setup_arch_memory(void) static void __init highmem_init(void) { #ifdef CONFIG_HIGHMEM - unsigned long tmp; - memblock_phys_free(high_mem_start, high_mem_sz); - for (tmp = min_high_pfn; tmp < max_high_pfn; tmp++) - free_highmem_page(pfn_to_page(tmp)); #endif }
@@ -176,8 +172,8 @@ static void __init highmem_init(void) */ void __init mem_init(void) { - memblock_free_all(); highmem_init(); + memblock_free_all(); BUILD_BUG_ON((PTRS_PER_PGD * sizeof(pgd_t)) > PAGE_SIZE); BUILD_BUG_ON((PTRS_PER_PUD * sizeof(pud_t)) > PAGE_SIZE);
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index d4bcc745a044..7bb5ce02b9b5 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c@@ -237,33 +237,6 @@ static inline void poison_init_mem(void *s, size_t count) *p++ = 0xe7fddef0; } -static void __init free_highpages(void) -{ -#ifdef CONFIG_HIGHMEM - unsigned long max_low = max_low_pfn; - phys_addr_t range_start, range_end; - u64 i; - - /* set highmem page free */ - for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, - &range_start, &range_end, NULL) { - unsigned long start = PFN_UP(range_start); - unsigned long end = PFN_DOWN(range_end); - - /* Ignore complete lowmem entries */ - if (end <= max_low) - continue; - - /* Truncate partial highmem entries */ - if (start < max_low) - start = max_low; - - for (; start < end; start++) - free_highmem_page(pfn_to_page(start)); - } -#endif -} - /* * mem_init() marks the free areas in the mem_map and tells us how much * memory is free. This is done after various parts of the system have
@@ -283,8 +256,6 @@ void __init mem_init(void) /* this will put all unused low memory onto the freelists */ memblock_free_all(); - free_highpages(); - /* * Check boundaries twice: Some fundamental inconsistencies can * be detected at build time already.
diff --git a/arch/csky/mm/init.c b/arch/csky/mm/init.c
index a22801aa503a..3914c2b873da 100644
--- a/arch/csky/mm/init.c
+++ b/arch/csky/mm/init.c@@ -44,21 +44,7 @@ EXPORT_SYMBOL(empty_zero_page); void __init mem_init(void) { -#ifdef CONFIG_HIGHMEM - unsigned long tmp; -#endif - memblock_free_all(); - -#ifdef CONFIG_HIGHMEM - for (tmp = highstart_pfn; tmp < highend_pfn; tmp++) { - struct page *page = pfn_to_page(tmp); - - /* FIXME not sure about */ - if (!memblock_is_reserved(tmp << PAGE_SHIFT)) - free_highmem_page(page); - } -#endif } void free_initmem(void)
diff --git a/arch/microblaze/mm/init.c b/arch/microblaze/mm/init.c
index 7e2e342e84c5..3e664e0efc33 100644
--- a/arch/microblaze/mm/init.c
+++ b/arch/microblaze/mm/init.c@@ -52,19 +52,6 @@ static void __init highmem_init(void) map_page(PKMAP_BASE, 0, 0); /* XXX gross */ pkmap_page_table = virt_to_kpte(PKMAP_BASE); } - -static void __meminit highmem_setup(void) -{ - unsigned long pfn; - - for (pfn = max_low_pfn; pfn < max_pfn; ++pfn) { - struct page *page = pfn_to_page(pfn); - - /* FIXME not sure about */ - if (!memblock_is_reserved(pfn << PAGE_SHIFT)) - free_highmem_page(page); - } -} #endif /* CONFIG_HIGHMEM */ /*
@@ -122,9 +109,6 @@ void __init mem_init(void) { /* this will put all memory onto the freelists */ memblock_free_all(); -#ifdef CONFIG_HIGHMEM - highmem_setup(); -#endif mem_init_done = 1; }
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index ed9dde6a00f7..075177e817ac 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c@@ -425,25 +425,6 @@ void __init paging_init(void) static struct kcore_list kcore_kseg0; #endif -static inline void __init mem_init_free_highmem(void) -{ -#ifdef CONFIG_HIGHMEM - unsigned long tmp; - - if (cpu_has_dc_aliases) - return; - - for (tmp = highstart_pfn; tmp < highend_pfn; tmp++) { - struct page *page = pfn_to_page(tmp); - - if (!memblock_is_memory(PFN_PHYS(tmp))) - SetPageReserved(page); - else - free_highmem_page(page); - } -#endif -} - void __init mem_init(void) { /*
@@ -454,7 +435,6 @@ void __init mem_init(void) maar_init(); setup_zero_pages(); /* Setup zeroed pages. */ - mem_init_free_highmem(); memblock_free_all(); #ifdef CONFIG_64BIT
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index c7708c8fad29..1bc94bca9944 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c@@ -297,20 +297,6 @@ void __init mem_init(void) memblock_free_all(); -#ifdef CONFIG_HIGHMEM - { - unsigned long pfn, highmem_mapnr; - - highmem_mapnr = lowmem_end_addr >> PAGE_SHIFT; - for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) { - phys_addr_t paddr = (phys_addr_t)pfn << PAGE_SHIFT; - struct page *page = pfn_to_page(pfn); - if (memblock_is_memory(paddr) && !memblock_is_reserved(paddr)) - free_highmem_page(page); - } - } -#endif /* CONFIG_HIGHMEM */ - #if defined(CONFIG_PPC_E500) && !defined(CONFIG_SMP) /* * If smp is enabled, next_tlbcam_idx is initialized in the cpu up
diff --git a/arch/sparc/mm/init_32.c b/arch/sparc/mm/init_32.c
index 81a468a9c223..043e9b6fadd0 100644
--- a/arch/sparc/mm/init_32.c
+++ b/arch/sparc/mm/init_32.c@@ -232,18 +232,6 @@ static void __init taint_real_pages(void) } } -static void map_high_region(unsigned long start_pfn, unsigned long end_pfn) -{ - unsigned long tmp; - -#ifdef CONFIG_DEBUG_HIGHMEM - printk("mapping high region %08lx - %08lx\n", start_pfn, end_pfn); -#endif - - for (tmp = start_pfn; tmp < end_pfn; tmp++) - free_highmem_page(pfn_to_page(tmp)); -} - void __init mem_init(void) { int i;
@@ -276,19 +264,6 @@ void __init mem_init(void) taint_real_pages(); memblock_free_all(); - - for (i = 0; sp_banks[i].num_bytes != 0; i++) { - unsigned long start_pfn = sp_banks[i].base_addr >> PAGE_SHIFT; - unsigned long end_pfn = (sp_banks[i].base_addr + sp_banks[i].num_bytes) >> PAGE_SHIFT; - - if (end_pfn <= highstart_pfn) - continue; - - if (start_pfn < highstart_pfn) - start_pfn = highstart_pfn; - - map_high_region(start_pfn, end_pfn); - } } void sparc_flush_page_to_ram(struct page *page)
diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h
index 731ee7cc40a5..585bdadba47d 100644
--- a/arch/x86/include/asm/highmem.h
+++ b/arch/x86/include/asm/highmem.h@@ -69,9 +69,6 @@ extern unsigned long highstart_pfn, highend_pfn; arch_flush_lazy_mmu_mode(); \ } while (0) -extern void add_highpages_with_active_regions(int nid, unsigned long start_pfn, - unsigned long end_pfn); - #endif /* __KERNEL__ */ #endif /* _ASM_X86_HIGHMEM_H */
diff --git a/arch/x86/include/asm/numa.h b/arch/x86/include/asm/numa.h
index 5469d7a7c40f..53ba39ce010c 100644
--- a/arch/x86/include/asm/numa.h
+++ b/arch/x86/include/asm/numa.h@@ -41,10 +41,6 @@ static inline int numa_cpu_node(int cpu) } #endif /* CONFIG_NUMA */ -#ifdef CONFIG_X86_32 -# include <asm/numa_32.h> -#endif - #ifdef CONFIG_NUMA extern void numa_set_node(int cpu, int node); extern void numa_clear_node(int cpu);
diff --git a/arch/x86/include/asm/numa_32.h b/arch/x86/include/asm/numa_32.h
deleted file mode 100644
index 9c8e9e85be77..000000000000
--- a/arch/x86/include/asm/numa_32.h
+++ /dev/null@@ -1,13 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _ASM_X86_NUMA_32_H -#define _ASM_X86_NUMA_32_H - -#ifdef CONFIG_HIGHMEM -extern void set_highmem_pages_init(void); -#else -static inline void set_highmem_pages_init(void) -{ -} -#endif - -#endif /* _ASM_X86_NUMA_32_H */
diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile
index 690fbf48e853..52fbf0a60858 100644
--- a/arch/x86/mm/Makefile
+++ b/arch/x86/mm/Makefile@@ -42,8 +42,6 @@ obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o obj-$(CONFIG_PTDUMP_CORE) += dump_pagetables.o obj-$(CONFIG_PTDUMP_DEBUGFS) += debug_pagetables.o -obj-$(CONFIG_HIGHMEM) += highmem_32.o - KASAN_SANITIZE_kasan_init_$(BITS).o := n obj-$(CONFIG_KASAN) += kasan_init_$(BITS).o
diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
deleted file mode 100644
index d9efa35711ee..000000000000
--- a/arch/x86/mm/highmem_32.c
+++ /dev/null@@ -1,34 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -#include <linux/highmem.h> -#include <linux/export.h> -#include <linux/swap.h> /* for totalram_pages */ -#include <linux/memblock.h> -#include <asm/numa.h> - -void __init set_highmem_pages_init(void) -{ - struct zone *zone; - int nid; - - /* - * Explicitly reset zone->managed_pages because set_highmem_pages_init() - * is invoked before memblock_free_all() - */ - reset_all_zones_managed_pages(); - for_each_zone(zone) { - unsigned long zone_start_pfn, zone_end_pfn; - - if (!is_highmem(zone)) - continue; - - zone_start_pfn = zone->zone_start_pfn; - zone_end_pfn = zone_start_pfn + zone->spanned_pages; - - nid = zone_to_nid(zone); - printk(KERN_INFO "Initializing %s for node %d (%08lx:%08lx)\n", - zone->name, nid, zone_start_pfn, zone_end_pfn); - - add_highpages_with_active_regions(nid, zone_start_pfn, - zone_end_pfn); - } -}
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c
index 801b659ead0c..9ee8ec2bc5d1 100644
--- a/arch/x86/mm/init_32.c
+++ b/arch/x86/mm/init_32.c@@ -394,23 +394,6 @@ static void __init permanent_kmaps_init(pgd_t *pgd_base) pkmap_page_table = virt_to_kpte(vaddr); } - -void __init add_highpages_with_active_regions(int nid, - unsigned long start_pfn, unsigned long end_pfn) -{ - phys_addr_t start, end; - u64 i; - - for_each_free_mem_range(i, nid, MEMBLOCK_NONE, &start, &end, NULL) { - unsigned long pfn = clamp_t(unsigned long, PFN_UP(start), - start_pfn, end_pfn); - unsigned long e_pfn = clamp_t(unsigned long, PFN_DOWN(end), - start_pfn, end_pfn); - for ( ; pfn < e_pfn; pfn++) - if (pfn_valid(pfn)) - free_highmem_page(pfn_to_page(pfn)); - } -} #else static inline void permanent_kmaps_init(pgd_t *pgd_base) {
@@ -715,17 +698,6 @@ void __init mem_init(void) #ifdef CONFIG_FLATMEM BUG_ON(!mem_map); #endif - /* - * With CONFIG_DEBUG_PAGEALLOC initialization of highmem pages has to - * be done before memblock_free_all(). Memblock use free low memory for - * temporary data (see find_range_array()) and for this purpose can use - * pages that was already passed to the buddy allocator, hence marked as - * not accessible in the page tables when compiled with - * CONFIG_DEBUG_PAGEALLOC. Otherwise order of initialization is not - * important here. - */ - set_highmem_pages_init(); - /* this will put all low memory onto the freelists */ memblock_free_all();
diff --git a/arch/xtensa/mm/init.c b/arch/xtensa/mm/init.c
index 9b662477b3d4..47ecbe28263e 100644
--- a/arch/xtensa/mm/init.c
+++ b/arch/xtensa/mm/init.c@@ -129,41 +129,12 @@ void __init zones_init(void) print_vm_layout(); } -static void __init free_highpages(void) -{ -#ifdef CONFIG_HIGHMEM - unsigned long max_low = max_low_pfn; - phys_addr_t range_start, range_end; - u64 i; - - /* set highmem page free */ - for_each_free_mem_range(i, NUMA_NO_NODE, MEMBLOCK_NONE, - &range_start, &range_end, NULL) { - unsigned long start = PFN_UP(range_start); - unsigned long end = PFN_DOWN(range_end); - - /* Ignore complete lowmem entries */ - if (end <= max_low) - continue; - - /* Truncate partial highmem entries */ - if (start < max_low) - start = max_low; - - for (; start < end; start++) - free_highmem_page(pfn_to_page(start)); - } -#endif -} - /* * Initialize memory pages. */ void __init mem_init(void) { - free_highpages(); - memblock_free_all(); }
diff --git a/include/linux/mm.h b/include/linux/mm.h
index fdf20503850e..6fccd3b3248c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -3172,7 +3172,6 @@ extern void reserve_bootmem_region(phys_addr_t start, /* Free the reserved page into the buddy system, so it gets managed. */ void free_reserved_page(struct page *page); -#define free_highmem_page(page) free_reserved_page(page) static inline void mark_page_reserved(struct page *page) {
diff --git a/mm/memblock.c b/mm/memblock.c
index 95af35fd1389..64ae678cd1d1 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c@@ -2164,8 +2164,7 @@ static unsigned long __init __free_memory_core(phys_addr_t start, phys_addr_t end) { unsigned long start_pfn = PFN_UP(start); - unsigned long end_pfn = min_t(unsigned long, - PFN_DOWN(end), max_low_pfn); + unsigned long end_pfn = PFN_DOWN(end); if (start_pfn >= end_pfn) return 0;
--
2.47.2