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Subject[PATCH V7 2/4] LoongArch: Add sparse memory vmemmap support
Date
From: Feiyang Chen <chenfeiyang@loongson.cn>

Add sparse memory vmemmap support for LoongArch. SPARSEMEM_VMEMMAP
uses a virtually mapped memmap to optimise pfn_to_page and page_to_pfn
operations. This is the most efficient option when sufficient kernel
resources are available.

Signed-off-by: Min Zhou <zhoumin@loongson.cn>
Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/pgtable.h | 6 ++-
arch/loongarch/include/asm/sparsemem.h | 8 +++
arch/loongarch/mm/init.c | 73 +++++++++++++++++++++++++-
include/linux/mm.h | 2 +
mm/sparse-vmemmap.c | 10 ++++
6 files changed, 98 insertions(+), 2 deletions(-)

diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 1281128d9fce..cff781d92c81 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -418,6 +418,7 @@ config ARCH_FLATMEM_ENABLE

config ARCH_SPARSEMEM_ENABLE
def_bool y
+ select SPARSEMEM_VMEMMAP_ENABLE
help
Say Y to support efficient handling of sparse physical memory,
for architectures which are either NUMA (Non-Uniform Memory Access)
diff --git a/arch/loongarch/include/asm/pgtable.h b/arch/loongarch/include/asm/pgtable.h
index 9c811c3f7572..adb5a3d2ed4f 100644
--- a/arch/loongarch/include/asm/pgtable.h
+++ b/arch/loongarch/include/asm/pgtable.h
@@ -65,6 +65,7 @@
#include <linux/mmzone.h>
#include <asm/fixmap.h>
#include <asm/io.h>
+#include <asm/sparsemem.h>

struct mm_struct;
struct vm_area_struct;
@@ -92,7 +93,10 @@ extern unsigned long zero_page_mask;
#define VMALLOC_START MODULES_END
#define VMALLOC_END \
(vm_map_base + \
- min(PTRS_PER_PGD * PTRS_PER_PUD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE, (1UL << cpu_vabits)) - PMD_SIZE)
+ min(PTRS_PER_PGD * PTRS_PER_PUD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE, (1UL << cpu_vabits)) - PMD_SIZE - VMEMMAP_SIZE)
+
+#define vmemmap ((struct page *)((VMALLOC_END + PMD_SIZE) & PMD_MASK))
+#define VMEMMAP_END ((unsigned long)vmemmap + VMEMMAP_SIZE - 1)

#define pte_ERROR(e) \
pr_err("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
diff --git a/arch/loongarch/include/asm/sparsemem.h b/arch/loongarch/include/asm/sparsemem.h
index 3d18cdf1b069..a1e440f6bec7 100644
--- a/arch/loongarch/include/asm/sparsemem.h
+++ b/arch/loongarch/include/asm/sparsemem.h
@@ -11,6 +11,14 @@
#define SECTION_SIZE_BITS 29 /* 2^29 = Largest Huge Page Size */
#define MAX_PHYSMEM_BITS 48

+#ifndef CONFIG_SPARSEMEM_VMEMMAP
+#define VMEMMAP_SIZE 0
+#else
+#define VMEMMAP_SIZE (sizeof(struct page) * (1UL << (cpu_pabits + 1 - PAGE_SHIFT)))
+#endif
+
+#include <linux/mm_types.h>
+
#endif /* CONFIG_SPARSEMEM */

#ifdef CONFIG_MEMORY_HOTPLUG
diff --git a/arch/loongarch/mm/init.c b/arch/loongarch/mm/init.c
index 7094a68c9b83..78f71f9bf295 100644
--- a/arch/loongarch/mm/init.c
+++ b/arch/loongarch/mm/init.c
@@ -22,7 +22,7 @@
#include <linux/pfn.h>
#include <linux/hardirq.h>
#include <linux/gfp.h>
-#include <linux/initrd.h>
+#include <linux/hugetlb.h>
#include <linux/mmzone.h>

#include <asm/asm-offsets.h>
@@ -157,6 +157,77 @@ void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
#endif
#endif

+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+static int __meminit vmemmap_populate_hugepages(unsigned long start, unsigned long end,
+ int node, struct vmem_altmap *altmap)
+{
+ unsigned long addr = start;
+ unsigned long next;
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+ pmd_t *pmd;
+
+ for (addr = start; addr < end; addr = next) {
+ next = pmd_addr_end(addr, end);
+
+ pgd = vmemmap_pgd_populate(addr, node);
+ if (!pgd)
+ return -ENOMEM;
+ p4d = vmemmap_p4d_populate(pgd, addr, node);
+ if (!p4d)
+ return -ENOMEM;
+ pud = vmemmap_pud_populate(p4d, addr, node);
+ if (!pud)
+ return -ENOMEM;
+
+ pmd = pmd_offset(pud, addr);
+ if (pmd_none(*pmd)) {
+ void *p = NULL;
+
+ p = vmemmap_alloc_block_buf(PMD_SIZE, node, NULL);
+ if (p) {
+ pmd_t entry;
+
+ entry = pfn_pmd(virt_to_pfn(p), PAGE_KERNEL);
+ pmd_val(entry) |= _PAGE_HUGE | _PAGE_HGLOBAL;
+ set_pmd_at(&init_mm, addr, pmd, entry);
+
+ continue;
+ }
+ } else if (pmd_val(*pmd) & _PAGE_HUGE) {
+ vmemmap_verify((pte_t *)pmd, node, addr, next);
+ continue;
+ }
+ if (vmemmap_populate_basepages(addr, next, node, NULL))
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+#if CONFIG_PGTABLE_LEVELS == 2
+int __meminit vmemmap_populate(unsigned long start, unsigned long end,
+ int node, struct vmem_altmap *altmap)
+{
+ return vmemmap_populate_basepages(start, end, node, NULL);
+}
+#else
+int __meminit vmemmap_populate(unsigned long start, unsigned long end,
+ int node, struct vmem_altmap *altmap)
+{
+ return vmemmap_populate_hugepages(start, end, node, NULL);
+}
+#endif
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+void vmemmap_free(unsigned long start, unsigned long end,
+ struct vmem_altmap *altmap)
+{
+}
+#endif
+#endif
+
/*
* Align swapper_pg_dir in to 64K, allows its address to be loaded
* with a single LUI instruction in the TLB handlers. If we used
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7898e29bcfb5..16bee6513f1a 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3207,6 +3207,8 @@ void *sparse_buffer_alloc(unsigned long size);
struct page * __populate_section_memmap(unsigned long pfn,
unsigned long nr_pages, int nid, struct vmem_altmap *altmap,
struct dev_pagemap *pgmap);
+void pmd_init(void *addr);
+void pud_init(void *addr);
pgd_t *vmemmap_pgd_populate(unsigned long addr, int node);
p4d_t *vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node);
pud_t *vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node);
diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
index dbbd1a7e65f3..0abcb0a5f1b5 100644
--- a/mm/sparse-vmemmap.c
+++ b/mm/sparse-vmemmap.c
@@ -595,6 +595,10 @@ pmd_t * __meminit vmemmap_pmd_populate(pud_t *pud, unsigned long addr, int node)
return pmd;
}

+void __weak __meminit pmd_init(void *addr)
+{
+}
+
pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
{
pud_t *pud = pud_offset(p4d, addr);
@@ -602,11 +606,16 @@ pud_t * __meminit vmemmap_pud_populate(p4d_t *p4d, unsigned long addr, int node)
void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
if (!p)
return NULL;
+ pmd_init(p);
pud_populate(&init_mm, pud, p);
}
return pud;
}

+void __weak __meminit pud_init(void *addr)
+{
+}
+
p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
{
p4d_t *p4d = p4d_offset(pgd, addr);
@@ -614,6 +623,7 @@ p4d_t * __meminit vmemmap_p4d_populate(pgd_t *pgd, unsigned long addr, int node)
void *p = vmemmap_alloc_block_zero(PAGE_SIZE, node);
if (!p)
return NULL;
+ pud_init(p);
p4d_populate(&init_mm, p4d, p);
}
return p4d;
--
2.31.1
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