[PATCH 2/3] LoongArch: Add sparse memory vmemmap support
Muchun Song
songmuchun at bytedance.com
Mon Jun 27 03:33:07 PDT 2022
On Sat, Jun 25, 2022 at 5:54 PM Huacai Chen <chenhuacai at loongson.cn> wrote:
>
> From: Feiyang Chen <chenfeiyang at 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 at loongson.cn>
> Signed-off-by: Huacai Chen <chenhuacai at loongson.cn>
> Signed-off-by: Feiyang Chen <chenfeiyang at loongson.cn>
> ---
> arch/loongarch/Kconfig | 2 +
> arch/loongarch/include/asm/pgtable.h | 5 +-
> arch/loongarch/include/asm/sparsemem.h | 8 +++
> arch/loongarch/mm/init.c | 71 +++++++++++++++++++++++++-
> include/linux/mm.h | 2 +
> mm/sparse-vmemmap.c | 10 ++++
> 6 files changed, 96 insertions(+), 2 deletions(-)
>
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index dc19cf3071ea..8e56ca28165e 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -49,6 +49,7 @@ config LOONGARCH
> select ARCH_USE_QUEUED_RWLOCKS
> select ARCH_USE_QUEUED_SPINLOCKS
> select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
> + select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
I think this should be a separate patch to enable HVO (HugeTLB Vmemmap
Optimization) since it is irrelevant to this patch.
Thanks.
> select ARCH_WANTS_NO_INSTR
> select BUILDTIME_TABLE_SORT
> select COMMON_CLK
> @@ -422,6 +423,7 @@ 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..b701ec7a0309 100644
> --- a/arch/loongarch/include/asm/pgtable.h
> +++ b/arch/loongarch/include/asm/pgtable.h
> @@ -92,7 +92,10 @@ 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..35128229fe46 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 +157,75 @@ void arch_remove_memory(u64 start, u64 size, struct vmem_altmap *altmap)
> #endif
> #endif
>
> +#ifdef CONFIG_SPARSEMEM_VMEMMAP
> +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
> +
> +void vmemmap_free(unsigned long start, unsigned long end,
> + struct vmem_altmap *altmap)
> +{
> +}
> +#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 bc8f326be0ce..3472b924a1ea 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -3203,6 +3203,8 @@ 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 f4fa61dbbee3..33e2a1ceee72 100644
> --- a/mm/sparse-vmemmap.c
> +++ b/mm/sparse-vmemmap.c
> @@ -587,6 +587,10 @@ 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);
> @@ -594,11 +598,16 @@ 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);
> @@ -606,6 +615,7 @@ 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;
> --
> 2.27.0
>
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