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authorGerald Schaefer <gerald.schaefer@de.ibm.com>2012-10-09 03:30:07 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2012-10-09 11:22:29 +0400
commite3ebcf64381188a2744a9829a4eb5c2b60f1974c (patch)
tree6c2bc18729bd6fc12b93d82403fad6afec319c3b
parent15626062f4a98279c59a2a5208c496cf65cbf8c0 (diff)
downloadlinux-e3ebcf64381188a2744a9829a4eb5c2b60f1974c.tar.xz
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>
-rw-r--r--include/asm-generic/pgtable.h8
-rw-r--r--include/linux/huge_mm.h1
-rw-r--r--mm/huge_memory.c50
-rw-r--r--mm/pgtable-generic.c39
4 files changed, 55 insertions, 43 deletions
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index c9a612069c8e..044939f21c16 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -162,6 +162,14 @@ extern void pmdp_splitting_flush(struct vm_area_struct *vma,
unsigned long address, pmd_t *pmdp);
#endif
+#ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
+extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable);
+#endif
+
+#ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
+extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm);
+#endif
+
#ifndef __HAVE_ARCH_PTE_SAME
static inline int pte_same(pte_t pte_a, pte_t pte_b)
{
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 4c59b1131187..6ab47af5a849 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -11,7 +11,6 @@ extern int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
extern int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pmd_t *pmd,
pmd_t orig_pmd);
-extern pgtable_t get_pmd_huge_pte(struct mm_struct *mm);
extern struct page *follow_trans_huge_pmd(struct mm_struct *mm,
unsigned long addr,
pmd_t *pmd,
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e19cc426c522..9ea6d1953765 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -598,19 +598,6 @@ out:
}
__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 @@ static int __do_huge_pmd_anonymous_page(struct mm_struct *mm,
*/
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 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
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 @@ out:
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 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
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 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
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 @@ static int __split_huge_page_map(struct page *page,
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 @@ static void collapse_huge_page(struct mm_struct *mm,
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 @@ static void collapse_huge_page(struct mm_struct *mm,
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 74c0ddaa6fa0..29867e083d37 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -120,3 +120,42 @@ void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
}
#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