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mm: hugetlb_vmemmap: use walk_page_range_novma() to simplify the code 

It is unnecessary to implement a series of dedicated page table walking
helpers since there is already a general one walk_page_range_novma().  So
use it to simplify the code.

Link: https://lkml.kernel.org/r/20231127084645.27017-3-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Muchun Song 2023-11-27 16:46:43 +08:00 committed by Andrew Morton
parent b123d09304
commit fb93ed6334
1 changed files with 43 additions and 113 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

156
mm/hugetlb_vmemmap.c
View File

@ -14,6 +14,7 @@
#include <linux/moduleparam.h>
#include <linux/bootmem_info.h>
#include <linux/mmdebug.h>
#include <linux/pagewalk.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#include "hugetlb_vmemmap.h"
@ -45,21 +46,14 @@ struct vmemmap_remap_walk {
unsigned long flags;
};
static int split_vmemmap_huge_pmd(pmd_t *pmd, unsigned long start, bool flush)
static int vmemmap_split_pmd(pmd_t *pmd, struct page *head, unsigned long start,
struct vmemmap_remap_walk *walk)
{
pmd_t __pmd;
int i;
unsigned long addr = start;
struct page *head;
pte_t *pgtable;
spin_lock(&init_mm.page_table_lock);
head = pmd_leaf(*pmd) ? pmd_page(*pmd) : NULL;
spin_unlock(&init_mm.page_table_lock);
if (!head)
return 0;
pgtable = pte_alloc_one_kernel(&init_mm);
if (!pgtable)
return -ENOMEM;
@ -88,7 +82,7 @@ static int split_vmemmap_huge_pmd(pmd_t *pmd, unsigned long start, bool flush)
/* Make pte visible before pmd. See comment in pmd_install(). */
smp_wmb();
pmd_populate_kernel(&init_mm, pmd, pgtable);
if (flush)
if (!(walk->flags & VMEMMAP_SPLIT_NO_TLB_FLUSH))
flush_tlb_kernel_range(start, start + PMD_SIZE);
} else {
pte_free_kernel(&init_mm, pgtable);
@ -98,123 +92,59 @@ static int split_vmemmap_huge_pmd(pmd_t *pmd, unsigned long start, bool flush)
return 0;
}
static void vmemmap_pte_range(pmd_t *pmd, unsigned long addr,
unsigned long end,
struct vmemmap_remap_walk *walk)
static int vmemmap_pmd_entry(pmd_t *pmd, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
pte_t *pte = pte_offset_kernel(pmd, addr);
struct page *head;
struct vmemmap_remap_walk *vmemmap_walk = walk->private;
/* Only splitting, not remapping the vmemmap pages. */
if (!vmemmap_walk->remap_pte)
walk->action = ACTION_CONTINUE;
spin_lock(&init_mm.page_table_lock);
head = pmd_leaf(*pmd) ? pmd_page(*pmd) : NULL;
spin_unlock(&init_mm.page_table_lock);
if (!head)
return 0;
return vmemmap_split_pmd(pmd, head, addr & PMD_MASK, vmemmap_walk);
}
static int vmemmap_pte_entry(pte_t *pte, unsigned long addr,
unsigned long next, struct mm_walk *walk)
{
struct vmemmap_remap_walk *vmemmap_walk = walk->private;
/*
* The reuse_page is found 'first' in table walk before we start
* remapping (which is calling @walk->remap_pte).
* The reuse_page is found 'first' in page table walking before
* starting remapping.
*/
if (!walk->reuse_page) {
walk->reuse_page = pte_page(ptep_get(pte));
/*
* Because the reuse address is part of the range that we are
* walking, skip the reuse address range.
*/
addr += PAGE_SIZE;
pte++;
walk->nr_walked++;
}
for (; addr != end; addr += PAGE_SIZE, pte++) {
walk->remap_pte(pte, addr, walk);
walk->nr_walked++;
}
}
static int vmemmap_pmd_range(pud_t *pud, unsigned long addr,
unsigned long end,
struct vmemmap_remap_walk *walk)
{
pmd_t *pmd;
unsigned long next;
pmd = pmd_offset(pud, addr);
do {
int ret;
ret = split_vmemmap_huge_pmd(pmd, addr & PMD_MASK,
!(walk->flags & VMEMMAP_SPLIT_NO_TLB_FLUSH));
if (ret)
return ret;
next = pmd_addr_end(addr, end);
/*
* We are only splitting, not remapping the hugetlb vmemmap
* pages.
*/
if (!walk->remap_pte)
continue;
vmemmap_pte_range(pmd, addr, next, walk);
} while (pmd++, addr = next, addr != end);
if (!vmemmap_walk->reuse_page)
vmemmap_walk->reuse_page = pte_page(ptep_get(pte));
else
vmemmap_walk->remap_pte(pte, addr, vmemmap_walk);
vmemmap_walk->nr_walked++;
return 0;
}
static int vmemmap_pud_range(p4d_t *p4d, unsigned long addr,
unsigned long end,
struct vmemmap_remap_walk *walk)
{
pud_t *pud;
unsigned long next;
pud = pud_offset(p4d, addr);
do {
int ret;
next = pud_addr_end(addr, end);
ret = vmemmap_pmd_range(pud, addr, next, walk);
if (ret)
return ret;
} while (pud++, addr = next, addr != end);
return 0;
}
static int vmemmap_p4d_range(pgd_t *pgd, unsigned long addr,
unsigned long end,
struct vmemmap_remap_walk *walk)
{
p4d_t *p4d;
unsigned long next;
p4d = p4d_offset(pgd, addr);
do {
int ret;
next = p4d_addr_end(addr, end);
ret = vmemmap_pud_range(p4d, addr, next, walk);
if (ret)
return ret;
} while (p4d++, addr = next, addr != end);
return 0;
}
static const struct mm_walk_ops vmemmap_remap_ops = {
.pmd_entry = vmemmap_pmd_entry,
.pte_entry = vmemmap_pte_entry,
};
static int vmemmap_remap_range(unsigned long start, unsigned long end,
struct vmemmap_remap_walk *walk)
{
unsigned long addr = start;
unsigned long next;
pgd_t *pgd;
int ret;
VM_BUG_ON(!PAGE_ALIGNED(start));
VM_BUG_ON(!PAGE_ALIGNED(end));
VM_BUG_ON(!PAGE_ALIGNED(start | end));
pgd = pgd_offset_k(addr);
do {
int ret;
next = pgd_addr_end(addr, end);
ret = vmemmap_p4d_range(pgd, addr, next, walk);
if (ret)
return ret;
} while (pgd++, addr = next, addr != end);
ret = walk_page_range_novma(&init_mm, start, end, &vmemmap_remap_ops,
NULL, walk);
if (ret)
return ret;
if (walk->remap_pte && !(walk->flags & VMEMMAP_REMAP_NO_TLB_FLUSH))
flush_tlb_kernel_range(start, end);