#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/setup.h>
+#include <asm/hugetlb.h>
+
+#ifdef CONFIG_HUGETLB_PAGE
#define PAGE_SHIFT_64K 16
#define PAGE_SHIFT_16M 24
}
#endif
-/*
- * We have 4 cases for pgds and pmds:
- * (1) invalid (all zeroes)
- * (2) pointer to next table, as normal; bottom 6 bits == 0
- * (3) leaf pte for huge page, bottom two bits != 00
- * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table
- */
-pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
-{
- pgd_t *pg;
- pud_t *pu;
- pmd_t *pm;
- pte_t *ret_pte;
- hugepd_t *hpdp = NULL;
- unsigned pdshift = PGDIR_SHIFT;
-
- if (shift)
- *shift = 0;
-
- pg = pgdir + pgd_index(ea);
-
- if (pgd_huge(*pg)) {
- ret_pte = (pte_t *) pg;
- goto out;
- } else if (is_hugepd(pg))
- hpdp = (hugepd_t *)pg;
- else if (!pgd_none(*pg)) {
- pdshift = PUD_SHIFT;
- pu = pud_offset(pg, ea);
-
- if (pud_huge(*pu)) {
- ret_pte = (pte_t *) pu;
- goto out;
- } else if (is_hugepd(pu))
- hpdp = (hugepd_t *)pu;
- else if (!pud_none(*pu)) {
- pdshift = PMD_SHIFT;
- pm = pmd_offset(pu, ea);
-
- if (pmd_huge(*pm)) {
- ret_pte = (pte_t *) pm;
- goto out;
- } else if (is_hugepd(pm))
- hpdp = (hugepd_t *)pm;
- else if (!pmd_none(*pm))
- return pte_offset_kernel(pm, ea);
- }
- }
- if (!hpdp)
- return NULL;
-
- ret_pte = hugepte_offset(hpdp, ea, pdshift);
- pdshift = hugepd_shift(*hpdp);
-out:
- if (shift)
- *shift = pdshift;
- return ret_pte;
-}
-EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte);
-
pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
+ /* Only called for hugetlbfs pages, hence can ignore THP */
return find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
}
int alloc_bootmem_huge_page(struct hstate *hstate)
{
struct huge_bootmem_page *m;
- int idx = shift_to_mmu_psize(hstate->order + PAGE_SHIFT);
+ int idx = shift_to_mmu_psize(huge_page_shift(hstate));
int nr_gpages = gpage_freearray[idx].nr_gpages;
if (nr_gpages == 0)
struct page *page;
unsigned shift;
unsigned long mask;
-
+ /*
+ * Transparent hugepages are handled by generic code. We can skip them
+ * here.
+ */
ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);
/* Verify it is a huge page else bail. */
- if (!ptep || !shift)
+ if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep))
return ERR_PTR(-EINVAL);
mask = (1UL << shift) - 1;
return NULL;
}
-int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
- unsigned long end, int write, struct page **pages, int *nr)
-{
- unsigned long mask;
- unsigned long pte_end;
- struct page *head, *page, *tail;
- pte_t pte;
- int refs;
-
- pte_end = (addr + sz) & ~(sz-1);
- if (pte_end < end)
- end = pte_end;
-
- pte = *ptep;
- mask = _PAGE_PRESENT | _PAGE_USER;
- if (write)
- mask |= _PAGE_RW;
-
- if ((pte_val(pte) & mask) != mask)
- return 0;
-
- /* hugepages are never "special" */
- VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
-
- refs = 0;
- head = pte_page(pte);
-
- page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
- tail = page;
- do {
- VM_BUG_ON(compound_head(page) != head);
- pages[*nr] = page;
- (*nr)++;
- page++;
- refs++;
- } while (addr += PAGE_SIZE, addr != end);
-
- if (!page_cache_add_speculative(head, refs)) {
- *nr -= refs;
- return 0;
- }
-
- if (unlikely(pte_val(pte) != pte_val(*ptep))) {
- /* Could be optimized better */
- *nr -= refs;
- while (refs--)
- put_page(head);
- return 0;
- }
-
- /*
- * Any tail page need their mapcount reference taken before we
- * return.
- */
- while (refs--) {
- if (PageTail(tail))
- get_huge_page_tail(tail);
- tail++;
- }
-
- return 1;
-}
-
static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
unsigned long sz)
{
}
}
}
+
+#endif /* CONFIG_HUGETLB_PAGE */
+
+/*
+ * We have 4 cases for pgds and pmds:
+ * (1) invalid (all zeroes)
+ * (2) pointer to next table, as normal; bottom 6 bits == 0
+ * (3) leaf pte for huge page, bottom two bits != 00
+ * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table
+ *
+ * So long as we atomically load page table pointers we are safe against teardown,
+ * we can follow the address down to the the page and take a ref on it.
+ */
+
+pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
+{
+ pgd_t pgd, *pgdp;
+ pud_t pud, *pudp;
+ pmd_t pmd, *pmdp;
+ pte_t *ret_pte;
+ hugepd_t *hpdp = NULL;
+ unsigned pdshift = PGDIR_SHIFT;
+
+ if (shift)
+ *shift = 0;
+
+ pgdp = pgdir + pgd_index(ea);
+ pgd = ACCESS_ONCE(*pgdp);
+ /*
+ * Always operate on the local stack value. This make sure the
+ * value don't get updated by a parallel THP split/collapse,
+ * page fault or a page unmap. The return pte_t * is still not
+ * stable. So should be checked there for above conditions.
+ */
+ if (pgd_none(pgd))
+ return NULL;
+ else if (pgd_huge(pgd)) {
+ ret_pte = (pte_t *) pgdp;
+ goto out;
+ } else if (is_hugepd(&pgd))
+ hpdp = (hugepd_t *)&pgd;
+ else {
+ /*
+ * Even if we end up with an unmap, the pgtable will not
+ * be freed, because we do an rcu free and here we are
+ * irq disabled
+ */
+ pdshift = PUD_SHIFT;
+ pudp = pud_offset(&pgd, ea);
+ pud = ACCESS_ONCE(*pudp);
+
+ if (pud_none(pud))
+ return NULL;
+ else if (pud_huge(pud)) {
+ ret_pte = (pte_t *) pudp;
+ goto out;
+ } else if (is_hugepd(&pud))
+ hpdp = (hugepd_t *)&pud;
+ else {
+ pdshift = PMD_SHIFT;
+ pmdp = pmd_offset(&pud, ea);
+ pmd = ACCESS_ONCE(*pmdp);
+ /*
+ * A hugepage collapse is captured by pmd_none, because
+ * it mark the pmd none and do a hpte invalidate.
+ *
+ * A hugepage split is captured by pmd_trans_splitting
+ * because we mark the pmd trans splitting and do a
+ * hpte invalidate
+ *
+ */
+ if (pmd_none(pmd) || pmd_trans_splitting(pmd))
+ return NULL;
+
+ if (pmd_huge(pmd) || pmd_large(pmd)) {
+ ret_pte = (pte_t *) pmdp;
+ goto out;
+ } else if (is_hugepd(&pmd))
+ hpdp = (hugepd_t *)&pmd;
+ else
+ return pte_offset_kernel(&pmd, ea);
+ }
+ }
+ if (!hpdp)
+ return NULL;
+
+ ret_pte = hugepte_offset(hpdp, ea, pdshift);
+ pdshift = hugepd_shift(*hpdp);
+out:
+ if (shift)
+ *shift = pdshift;
+ return ret_pte;
+}
+EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte);
+
+int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
+ unsigned long end, int write, struct page **pages, int *nr)
+{
+ unsigned long mask;
+ unsigned long pte_end;
+ struct page *head, *page, *tail;
+ pte_t pte;
+ int refs;
+
+ pte_end = (addr + sz) & ~(sz-1);
+ if (pte_end < end)
+ end = pte_end;
+
+ pte = ACCESS_ONCE(*ptep);
+ mask = _PAGE_PRESENT | _PAGE_USER;
+ if (write)
+ mask |= _PAGE_RW;
+
+ if ((pte_val(pte) & mask) != mask)
+ return 0;
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ /*
+ * check for splitting here
+ */
+ if (pmd_trans_splitting(pte_pmd(pte)))
+ return 0;
+#endif
+
+ /* hugepages are never "special" */
+ VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
+
+ refs = 0;
+ head = pte_page(pte);
+
+ page = head + ((addr & (sz-1)) >> PAGE_SHIFT);
+ tail = page;
+ do {
+ VM_BUG_ON(compound_head(page) != head);
+ pages[*nr] = page;
+ (*nr)++;
+ page++;
+ refs++;
+ } while (addr += PAGE_SIZE, addr != end);
+
+ if (!page_cache_add_speculative(head, refs)) {
+ *nr -= refs;
+ return 0;
+ }
+
+ if (unlikely(pte_val(pte) != pte_val(*ptep))) {
+ /* Could be optimized better */
+ *nr -= refs;
+ while (refs--)
+ put_page(head);
+ return 0;
+ }
+
+ /*
+ * Any tail page need their mapcount reference taken before we
+ * return.
+ */
+ while (refs--) {
+ if (PageTail(tail))
+ get_huge_page_tail(tail);
+ tail++;
+ }
+
+ return 1;
+}
projects / deliverable / linux.git / blobdiff