#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/sched.h>
+#include <linux/hugetlb.h>
static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
struct mm_walk *walk)
pmd = pmd_offset(pud, addr);
do {
+again:
next = pmd_addr_end(addr, end);
- if (pmd_none_or_clear_bad(pmd)) {
+ if (pmd_none(*pmd)) {
if (walk->pte_hole)
err = walk->pte_hole(addr, next, walk);
if (err)
break;
continue;
}
+ /*
+ * This implies that each ->pmd_entry() handler
+ * needs to know about pmd_trans_huge() pmds
+ */
if (walk->pmd_entry)
err = walk->pmd_entry(pmd, addr, next, walk);
- if (!err && walk->pte_entry)
- err = walk_pte_range(pmd, addr, next, walk);
+ if (err)
+ break;
+
+ /*
+ * Check this here so we only break down trans_huge
+ * pages when we _need_ to
+ */
+ if (!walk->pte_entry)
+ continue;
+
+ split_huge_page_pmd(walk->mm, pmd);
+ if (pmd_none_or_trans_huge_or_clear_bad(pmd))
+ goto again;
+ err = walk_pte_range(pmd, addr, next, walk);
if (err)
break;
} while (pmd++, addr = next, addr != end);
return err;
}
+#ifdef CONFIG_HUGETLB_PAGE
+static unsigned long hugetlb_entry_end(struct hstate *h, unsigned long addr,
+ unsigned long end)
+{
+ unsigned long boundary = (addr & huge_page_mask(h)) + huge_page_size(h);
+ return boundary < end ? boundary : end;
+}
+
+static int walk_hugetlb_range(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
+{
+ struct hstate *h = hstate_vma(vma);
+ unsigned long next;
+ unsigned long hmask = huge_page_mask(h);
+ pte_t *pte;
+ int err = 0;
+
+ do {
+ next = hugetlb_entry_end(h, addr, end);
+ pte = huge_pte_offset(walk->mm, addr & hmask);
+ if (pte && walk->hugetlb_entry)
+ err = walk->hugetlb_entry(pte, hmask, addr, next, walk);
+ if (err)
+ return err;
+ } while (addr = next, addr != end);
+
+ return 0;
+}
+
+static struct vm_area_struct* hugetlb_vma(unsigned long addr, struct mm_walk *walk)
+{
+ struct vm_area_struct *vma;
+
+ /* We don't need vma lookup at all. */
+ if (!walk->hugetlb_entry)
+ return NULL;
+
+ VM_BUG_ON(!rwsem_is_locked(&walk->mm->mmap_sem));
+ vma = find_vma(walk->mm, addr);
+ if (vma && vma->vm_start <= addr && is_vm_hugetlb_page(vma))
+ return vma;
+
+ return NULL;
+}
+
+#else /* CONFIG_HUGETLB_PAGE */
+static struct vm_area_struct* hugetlb_vma(unsigned long addr, struct mm_walk *walk)
+{
+ return NULL;
+}
+
+static int walk_hugetlb_range(struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end,
+ struct mm_walk *walk)
+{
+ return 0;
+}
+
+#endif /* CONFIG_HUGETLB_PAGE */
+
+
+
/**
* walk_page_range - walk a memory map's page tables with a callback
* @mm: memory map to walk
* associated range, and a copy of the original mm_walk for access to
* the ->private or ->mm fields.
*
- * No locks are taken, but the bottom level iterator will map PTE
+ * Usually no locks are taken, but splitting transparent huge page may
+ * take page table lock. And the bottom level iterator will map PTE
* directories from highmem if necessary.
*
* If any callback returns a non-zero value, the walk is aborted and
* the return value is propagated back to the caller. Otherwise 0 is returned.
+ *
+ * walk->mm->mmap_sem must be held for at least read if walk->hugetlb_entry
+ * is !NULL.
*/
int walk_page_range(unsigned long addr, unsigned long end,
struct mm_walk *walk)
pgd = pgd_offset(walk->mm, addr);
do {
+ struct vm_area_struct *vma;
+
next = pgd_addr_end(addr, end);
+
+ /*
+ * handle hugetlb vma individually because pagetable walk for
+ * the hugetlb page is dependent on the architecture and
+ * we can't handled it in the same manner as non-huge pages.
+ */
+ vma = hugetlb_vma(addr, walk);
+ if (vma) {
+ if (vma->vm_end < next)
+ next = vma->vm_end;
+ /*
+ * Hugepage is very tightly coupled with vma, so
+ * walk through hugetlb entries within a given vma.
+ */
+ err = walk_hugetlb_range(vma, addr, next, walk);
+ if (err)
+ break;
+ pgd = pgd_offset(walk->mm, next);
+ continue;
+ }
+
if (pgd_none_or_clear_bad(pgd)) {
if (walk->pte_hole)
err = walk->pte_hole(addr, next, walk);
if (err)
break;
+ pgd++;
continue;
}
if (walk->pgd_entry)
err = walk_pud_range(pgd, addr, next, walk);
if (err)
break;
- } while (pgd++, addr = next, addr != end);
+ pgd++;
+ } while (addr = next, addr != end);
return err;
}
projects / linux-flexiantxendom0.git / blobdiff