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-rw-r--r--fs/proc/task_mmu.c73
-rw-r--r--include/linux/huge_mm.h17
-rw-r--r--mm/huge_memory.c125
3 files changed, 101 insertions, 114 deletions
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 95264c0ef308..328843de6e9f 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -394,20 +394,11 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
pte_t *pte;
spinlock_t *ptl;
- spin_lock(&walk->mm->page_table_lock);
- if (pmd_trans_huge(*pmd)) {
- if (pmd_trans_splitting(*pmd)) {
- spin_unlock(&walk->mm->page_table_lock);
- wait_split_huge_page(vma->anon_vma, pmd);
- } else {
- smaps_pte_entry(*(pte_t *)pmd, addr,
- HPAGE_PMD_SIZE, walk);
- spin_unlock(&walk->mm->page_table_lock);
- mss->anonymous_thp += HPAGE_PMD_SIZE;
- return 0;
- }
- } else {
+ if (pmd_trans_huge_lock(pmd, vma) == 1) {
+ smaps_pte_entry(*(pte_t *)pmd, addr, HPAGE_PMD_SIZE, walk);
spin_unlock(&walk->mm->page_table_lock);
+ mss->anonymous_thp += HPAGE_PMD_SIZE;
+ return 0;
}
if (pmd_trans_unstable(pmd))
@@ -705,26 +696,19 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
/* find the first VMA at or above 'addr' */
vma = find_vma(walk->mm, addr);
spin_lock(&walk->mm->page_table_lock);
- if (pmd_trans_huge(*pmd)) {
- if (pmd_trans_splitting(*pmd)) {
- spin_unlock(&walk->mm->page_table_lock);
- wait_split_huge_page(vma->anon_vma, pmd);
- } else {
- for (; addr != end; addr += PAGE_SIZE) {
- unsigned long offset;
-
- offset = (addr & ~PAGEMAP_WALK_MASK) >>
- PAGE_SHIFT;
- pfn = thp_pmd_to_pagemap_entry(*pmd, offset);
- err = add_to_pagemap(addr, pfn, pm);
- if (err)
- break;
- }
- spin_unlock(&walk->mm->page_table_lock);
- return err;
+ if (pmd_trans_huge_lock(pmd, vma) == 1) {
+ for (; addr != end; addr += PAGE_SIZE) {
+ unsigned long offset;
+
+ offset = (addr & ~PAGEMAP_WALK_MASK) >>
+ PAGE_SHIFT;
+ pfn = thp_pmd_to_pagemap_entry(*pmd, offset);
+ err = add_to_pagemap(addr, pfn, pm);
+ if (err)
+ break;
}
- } else {
spin_unlock(&walk->mm->page_table_lock);
+ return err;
}
for (; addr != end; addr += PAGE_SIZE) {
@@ -992,24 +976,17 @@ static int gather_pte_stats(pmd_t *pmd, unsigned long addr,
pte_t *pte;
md = walk->private;
- spin_lock(&walk->mm->page_table_lock);
- if (pmd_trans_huge(*pmd)) {
- if (pmd_trans_splitting(*pmd)) {
- spin_unlock(&walk->mm->page_table_lock);
- wait_split_huge_page(md->vma->anon_vma, pmd);
- } else {
- pte_t huge_pte = *(pte_t *)pmd;
- struct page *page;
-
- page = can_gather_numa_stats(huge_pte, md->vma, addr);
- if (page)
- gather_stats(page, md, pte_dirty(huge_pte),
- HPAGE_PMD_SIZE/PAGE_SIZE);
- spin_unlock(&walk->mm->page_table_lock);
- return 0;
- }
- } else {
+
+ if (pmd_trans_huge_lock(pmd, md->vma) == 1) {
+ pte_t huge_pte = *(pte_t *)pmd;
+ struct page *page;
+
+ page = can_gather_numa_stats(huge_pte, md->vma, addr);
+ if (page)
+ gather_stats(page, md, pte_dirty(huge_pte),
+ HPAGE_PMD_SIZE/PAGE_SIZE);
spin_unlock(&walk->mm->page_table_lock);
+ return 0;
}
if (pmd_trans_unstable(pmd))
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 1b921299abc4..f56cacb4fec3 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -113,6 +113,18 @@ extern void __vma_adjust_trans_huge(struct vm_area_struct *vma,
unsigned long start,
unsigned long end,
long adjust_next);
+extern int __pmd_trans_huge_lock(pmd_t *pmd,
+ struct vm_area_struct *vma);
+/* mmap_sem must be held on entry */
+static inline int pmd_trans_huge_lock(pmd_t *pmd,
+ struct vm_area_struct *vma)
+{
+ VM_BUG_ON(!rwsem_is_locked(&vma->vm_mm->mmap_sem));
+ if (pmd_trans_huge(*pmd))
+ return __pmd_trans_huge_lock(pmd, vma);
+ else
+ return 0;
+}
static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
unsigned long start,
unsigned long end,
@@ -176,6 +188,11 @@ static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
long adjust_next)
{
}
+static inline int pmd_trans_huge_lock(pmd_t *pmd,
+ struct vm_area_struct *vma)
+{
+ return 0;
+}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif /* _LINUX_HUGE_MM_H */
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 8f7fc394f636..f0e5306eeb55 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1031,32 +1031,23 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
{
int ret = 0;
- spin_lock(&tlb->mm->page_table_lock);
- if (likely(pmd_trans_huge(*pmd))) {
- if (unlikely(pmd_trans_splitting(*pmd))) {
- spin_unlock(&tlb->mm->page_table_lock);
- wait_split_huge_page(vma->anon_vma,
- pmd);
- } else {
- struct page *page;
- pgtable_t pgtable;
- pgtable = get_pmd_huge_pte(tlb->mm);
- page = pmd_page(*pmd);
- pmd_clear(pmd);
- tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
- page_remove_rmap(page);
- VM_BUG_ON(page_mapcount(page) < 0);
- add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
- VM_BUG_ON(!PageHead(page));
- tlb->mm->nr_ptes--;
- spin_unlock(&tlb->mm->page_table_lock);
- tlb_remove_page(tlb, page);
- pte_free(tlb->mm, pgtable);
- ret = 1;
- }
- } else
+ if (__pmd_trans_huge_lock(pmd, vma) == 1) {
+ struct page *page;
+ pgtable_t pgtable;
+ pgtable = get_pmd_huge_pte(tlb->mm);
+ page = pmd_page(*pmd);
+ pmd_clear(pmd);
+ tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
+ page_remove_rmap(page);
+ VM_BUG_ON(page_mapcount(page) < 0);
+ add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
+ VM_BUG_ON(!PageHead(page));
+ tlb->mm->nr_ptes--;
spin_unlock(&tlb->mm->page_table_lock);
-
+ tlb_remove_page(tlb, page);
+ pte_free(tlb->mm, pgtable);
+ ret = 1;
+ }
return ret;
}
@@ -1066,21 +1057,15 @@ int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
{
int ret = 0;
- spin_lock(&vma->vm_mm->page_table_lock);
- if (likely(pmd_trans_huge(*pmd))) {
- ret = !pmd_trans_splitting(*pmd);
- spin_unlock(&vma->vm_mm->page_table_lock);
- if (unlikely(!ret))
- wait_split_huge_page(vma->anon_vma, pmd);
- else {
- /*
- * All logical pages in the range are present
- * if backed by a huge page.
- */
- memset(vec, 1, (end - addr) >> PAGE_SHIFT);
- }
- } else
+ if (__pmd_trans_huge_lock(pmd, vma) == 1) {
+ /*
+ * All logical pages in the range are present
+ * if backed by a huge page.
+ */
spin_unlock(&vma->vm_mm->page_table_lock);
+ memset(vec, 1, (end - addr) >> PAGE_SHIFT);
+ ret = 1;
+ }
return ret;
}
@@ -1110,20 +1095,11 @@ int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
goto out;
}
- spin_lock(&mm->page_table_lock);
- if (likely(pmd_trans_huge(*old_pmd))) {
- if (pmd_trans_splitting(*old_pmd)) {
- spin_unlock(&mm->page_table_lock);
- wait_split_huge_page(vma->anon_vma, old_pmd);
- ret = -1;
- } else {
- pmd = pmdp_get_and_clear(mm, old_addr, old_pmd);
- VM_BUG_ON(!pmd_none(*new_pmd));
- set_pmd_at(mm, new_addr, new_pmd, pmd);
- spin_unlock(&mm->page_table_lock);
- ret = 1;
- }
- } else {
+ ret = __pmd_trans_huge_lock(old_pmd, vma);
+ if (ret == 1) {
+ pmd = pmdp_get_and_clear(mm, old_addr, old_pmd);
+ VM_BUG_ON(!pmd_none(*new_pmd));
+ set_pmd_at(mm, new_addr, new_pmd, pmd);
spin_unlock(&mm->page_table_lock);
}
out:
@@ -1136,24 +1112,41 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
struct mm_struct *mm = vma->vm_mm;
int ret = 0;
- spin_lock(&mm->page_table_lock);
+ if (__pmd_trans_huge_lock(pmd, vma) == 1) {
+ pmd_t entry;
+ entry = pmdp_get_and_clear(mm, addr, pmd);
+ entry = pmd_modify(entry, newprot);
+ set_pmd_at(mm, addr, pmd, entry);
+ spin_unlock(&vma->vm_mm->page_table_lock);
+ ret = 1;
+ }
+
+ return ret;
+}
+
+/*
+ * Returns 1 if a given pmd maps a stable (not under splitting) thp.
+ * Returns -1 if it maps a thp under splitting. Returns 0 otherwise.
+ *
+ * Note that if it returns 1, this routine returns without unlocking page
+ * table locks. So callers must unlock them.
+ */
+int __pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma)
+{
+ spin_lock(&vma->vm_mm->page_table_lock);
if (likely(pmd_trans_huge(*pmd))) {
if (unlikely(pmd_trans_splitting(*pmd))) {
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(&vma->vm_mm->page_table_lock);
wait_split_huge_page(vma->anon_vma, pmd);
+ return -1;
} else {
- pmd_t entry;
-
- entry = pmdp_get_and_clear(mm, addr, pmd);
- entry = pmd_modify(entry, newprot);
- set_pmd_at(mm, addr, pmd, entry);
- spin_unlock(&vma->vm_mm->page_table_lock);
- ret = 1;
+ /* Thp mapped by 'pmd' is stable, so we can
+ * handle it as it is. */
+ return 1;
}
- } else
- spin_unlock(&vma->vm_mm->page_table_lock);
-
- return ret;
+ }
+ spin_unlock(&vma->vm_mm->page_table_lock);
+ return 0;
}
pmd_t *page_check_address_pmd(struct page *page,
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.