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mm/khugepaged: use start_addr/addr for improved readability

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When collapsing a pmd, there are two address in use:

  * address points to the start of pmd
  * address points to each individual page

Current naming makes it difficult to distinguish these two and is hence
error prone.

Considering the plan to collapse mTHP, name the first one `start_addr' and
the second `addr' for better readability and consistency.

Link: https://lkml.kernel.org/r/20250922140938.27343-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Suggested-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Nico Pache <npache@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Wei Yang 2025-09-22 14:09:38 +00:00 committed by Andrew Morton
parent dd83609b88
commit 1acc369373
1 changed files with 22 additions and 21 deletions
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43
mm/khugepaged.c
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@ -537,18 +537,19 @@ static void release_pte_pages(pte_t *pte, pte_t *_pte,
}
static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
unsigned long address,
unsigned long start_addr,
pte_t *pte,
struct collapse_control *cc,
struct list_head *compound_pagelist)
{
struct page *page = NULL;
struct folio *folio = NULL;
unsigned long addr = start_addr;
pte_t *_pte;
int none_or_zero = 0, shared = 0, result = SCAN_FAIL, referenced = 0;
for (_pte = pte; _pte < pte + HPAGE_PMD_NR;
_pte++, address += PAGE_SIZE) {
_pte++, addr += PAGE_SIZE) {
pte_t pteval = ptep_get(_pte);
if (pte_none(pteval) || (pte_present(pteval) &&
is_zero_pfn(pte_pfn(pteval)))) {
@ -571,7 +572,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
result = SCAN_PTE_UFFD_WP;
goto out;
}
page = vm_normal_page(vma, address, pteval);
page = vm_normal_page(vma, addr, pteval);
if (unlikely(!page) || unlikely(is_zone_device_page(page))) {
result = SCAN_PAGE_NULL;
goto out;
@ -656,8 +657,8 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
*/
if (cc->is_khugepaged &&
(pte_young(pteval) || folio_test_young(folio) ||
folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
address)))
folio_test_referenced(folio) ||
mmu_notifier_test_young(vma->vm_mm, addr)))
referenced++;
}
@ -986,21 +987,21 @@ static int check_pmd_still_valid(struct mm_struct *mm,
*/
static int __collapse_huge_page_swapin(struct mm_struct *mm,
struct vm_area_struct *vma,
unsigned long haddr, pmd_t *pmd,
unsigned long start_addr, pmd_t *pmd,
int referenced)
{
int swapped_in = 0;
vm_fault_t ret = 0;
unsigned long address, end = haddr + (HPAGE_PMD_NR * PAGE_SIZE);
unsigned long addr, end = start_addr + (HPAGE_PMD_NR * PAGE_SIZE);
int result;
pte_t *pte = NULL;
spinlock_t *ptl;
for (address = haddr; address < end; address += PAGE_SIZE) {
for (addr = start_addr; addr < end; addr += PAGE_SIZE) {
struct vm_fault vmf = {
.vma = vma,
.address = address,
.pgoff = linear_page_index(vma, address),
.address = addr,
.pgoff = linear_page_index(vma, addr),
.flags = FAULT_FLAG_ALLOW_RETRY,
.pmd = pmd,
};
@ -1010,7 +1011,7 @@ static int __collapse_huge_page_swapin(struct mm_struct *mm,
* Here the ptl is only used to check pte_same() in
* do_swap_page(), so readonly version is enough.
*/
pte = pte_offset_map_ro_nolock(mm, pmd, address, &ptl);
pte = pte_offset_map_ro_nolock(mm, pmd, addr, &ptl);
if (!pte) {
mmap_read_unlock(mm);
result = SCAN_PMD_NULL;
@ -1253,7 +1254,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
static int hpage_collapse_scan_pmd(struct mm_struct *mm,
struct vm_area_struct *vma,
unsigned long address, bool *mmap_locked,
unsigned long start_addr, bool *mmap_locked,
struct collapse_control *cc)
{
pmd_t *pmd;
@ -1262,26 +1263,26 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
int none_or_zero = 0, shared = 0;
struct page *page = NULL;
struct folio *folio = NULL;
unsigned long _address;
unsigned long addr;
spinlock_t *ptl;
int node = NUMA_NO_NODE, unmapped = 0;
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
VM_BUG_ON(start_addr & ~HPAGE_PMD_MASK);
result = find_pmd_or_thp_or_none(mm, address, &pmd);
result = find_pmd_or_thp_or_none(mm, start_addr, &pmd);
if (result != SCAN_SUCCEED)
goto out;
memset(cc->node_load, 0, sizeof(cc->node_load));
nodes_clear(cc->alloc_nmask);
pte = pte_offset_map_lock(mm, pmd, address, &ptl);
pte = pte_offset_map_lock(mm, pmd, start_addr, &ptl);
if (!pte) {
result = SCAN_PMD_NULL;
goto out;
}
for (_address = address, _pte = pte; _pte < pte + HPAGE_PMD_NR;
_pte++, _address += PAGE_SIZE) {
for (addr = start_addr, _pte = pte; _pte < pte + HPAGE_PMD_NR;
_pte++, addr += PAGE_SIZE) {
pte_t pteval = ptep_get(_pte);
if (is_swap_pte(pteval)) {
++unmapped;
@ -1329,7 +1330,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
goto out_unmap;
}
page = vm_normal_page(vma, _address, pteval);
page = vm_normal_page(vma, addr, pteval);
if (unlikely(!page) || unlikely(is_zone_device_page(page))) {
result = SCAN_PAGE_NULL;
goto out_unmap;
@ -1398,7 +1399,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
if (cc->is_khugepaged &&
(pte_young(pteval) || folio_test_young(folio) ||
folio_test_referenced(folio) ||
mmu_notifier_test_young(vma->vm_mm, _address)))
mmu_notifier_test_young(vma->vm_mm, addr)))
referenced++;
}
if (cc->is_khugepaged &&
@ -1411,7 +1412,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
out_unmap:
pte_unmap_unlock(pte, ptl);
if (result == SCAN_SUCCEED) {
result = collapse_huge_page(mm, address, referenced,
result = collapse_huge_page(mm, start_addr, referenced,
unmapped, cc);
/* collapse_huge_page will return with the mmap_lock released */
*mmap_locked = false;