thp: remove assumptions on pgtable_t type
The thp page table pre-allocation code currently assumes that pgtable_t is
of type "struct page *". This may not be true for all architectures, so
this patch removes that assumption by replacing the functions
prepare_pmd_huge_pte() and get_pmd_huge_pte() with two new functions that
can be defined architecture-specific.
It also removes two VM_BUG_ON checks for page_count() and page_mapcount()
operating on a pgtable_t. Apart from the VM_BUG_ON removal, there will be
no functional change introduced by this patch.
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e19cc42..9ea6d19 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -598,19 +598,6 @@
}
__setup("transparent_hugepage=", setup_transparent_hugepage);
-static void prepare_pmd_huge_pte(pgtable_t pgtable,
- struct mm_struct *mm)
-{
- assert_spin_locked(&mm->page_table_lock);
-
- /* FIFO */
- if (!mm->pmd_huge_pte)
- INIT_LIST_HEAD(&pgtable->lru);
- else
- list_add(&pgtable->lru, &mm->pmd_huge_pte->lru);
- mm->pmd_huge_pte = pgtable;
-}
-
static inline pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma)
{
if (likely(vma->vm_flags & VM_WRITE))
@@ -652,7 +639,7 @@
*/
page_add_new_anon_rmap(page, vma, haddr);
set_pmd_at(mm, haddr, pmd, entry);
- prepare_pmd_huge_pte(pgtable, mm);
+ pgtable_trans_huge_deposit(mm, pgtable);
add_mm_counter(mm, MM_ANONPAGES, HPAGE_PMD_NR);
mm->nr_ptes++;
spin_unlock(&mm->page_table_lock);
@@ -778,7 +765,7 @@
pmdp_set_wrprotect(src_mm, addr, src_pmd);
pmd = pmd_mkold(pmd_wrprotect(pmd));
set_pmd_at(dst_mm, addr, dst_pmd, pmd);
- prepare_pmd_huge_pte(pgtable, dst_mm);
+ pgtable_trans_huge_deposit(dst_mm, pgtable);
dst_mm->nr_ptes++;
ret = 0;
@@ -789,25 +776,6 @@
return ret;
}
-/* no "address" argument so destroys page coloring of some arch */
-pgtable_t get_pmd_huge_pte(struct mm_struct *mm)
-{
- pgtable_t pgtable;
-
- assert_spin_locked(&mm->page_table_lock);
-
- /* FIFO */
- pgtable = mm->pmd_huge_pte;
- if (list_empty(&pgtable->lru))
- mm->pmd_huge_pte = NULL;
- else {
- mm->pmd_huge_pte = list_entry(pgtable->lru.next,
- struct page, lru);
- list_del(&pgtable->lru);
- }
- return pgtable;
-}
-
static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
struct vm_area_struct *vma,
unsigned long address,
@@ -863,7 +831,7 @@
pmdp_clear_flush_notify(vma, haddr, pmd);
/* leave pmd empty until pte is filled */
- pgtable = get_pmd_huge_pte(mm);
+ pgtable = pgtable_trans_huge_withdraw(mm);
pmd_populate(mm, &_pmd, pgtable);
for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
@@ -1028,7 +996,7 @@
if (__pmd_trans_huge_lock(pmd, vma) == 1) {
struct page *page;
pgtable_t pgtable;
- pgtable = get_pmd_huge_pte(tlb->mm);
+ pgtable = pgtable_trans_huge_withdraw(tlb->mm);
page = pmd_page(*pmd);
pmd_clear(pmd);
tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
@@ -1345,11 +1313,11 @@
pmd = page_check_address_pmd(page, mm, address,
PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG);
if (pmd) {
- pgtable = get_pmd_huge_pte(mm);
+ pgtable = pgtable_trans_huge_withdraw(mm);
pmd_populate(mm, &_pmd, pgtable);
- for (i = 0, haddr = address; i < HPAGE_PMD_NR;
- i++, haddr += PAGE_SIZE) {
+ haddr = address;
+ for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) {
pte_t *pte, entry;
BUG_ON(PageCompound(page+i));
entry = mk_pte(page + i, vma->vm_page_prot);
@@ -2017,8 +1985,6 @@
pte_unmap(pte);
__SetPageUptodate(new_page);
pgtable = pmd_pgtable(_pmd);
- VM_BUG_ON(page_count(pgtable) != 1);
- VM_BUG_ON(page_mapcount(pgtable) != 0);
_pmd = mk_pmd(new_page, vma->vm_page_prot);
_pmd = maybe_pmd_mkwrite(pmd_mkdirty(_pmd), vma);
@@ -2036,7 +2002,7 @@
page_add_new_anon_rmap(new_page, vma, address);
set_pmd_at(mm, address, pmd, _pmd);
update_mmu_cache(vma, address, _pmd);
- prepare_pmd_huge_pte(pgtable, mm);
+ pgtable_trans_huge_deposit(mm, pgtable);
spin_unlock(&mm->page_table_lock);
*hpage = NULL;
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 74c0dda..29867e0 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -120,3 +120,42 @@
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
+
+#ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
+{
+ assert_spin_locked(&mm->page_table_lock);
+
+ /* FIFO */
+ if (!mm->pmd_huge_pte)
+ INIT_LIST_HEAD(&pgtable->lru);
+ else
+ list_add(&pgtable->lru, &mm->pmd_huge_pte->lru);
+ mm->pmd_huge_pte = pgtable;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif
+
+#ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+/* no "address" argument so destroys page coloring of some arch */
+pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm)
+{
+ pgtable_t pgtable;
+
+ assert_spin_locked(&mm->page_table_lock);
+
+ /* FIFO */
+ pgtable = mm->pmd_huge_pte;
+ if (list_empty(&pgtable->lru))
+ mm->pmd_huge_pte = NULL;
+ else {
+ mm->pmd_huge_pte = list_entry(pgtable->lru.next,
+ struct page, lru);
+ list_del(&pgtable->lru);
+ }
+ return pgtable;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif