X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=mm%2Fhuge_memory.c;h=4298abaae153033caafe1f8ac641fdef1dee097e;hb=94956eed14b4b16d401c8ad36d68df0608f968cb;hp=e2d1587be269bf475a5ce2c05e6d10d9648a2121;hpb=218f82e6249e79bd4cb38f27e4883770d6caa1da;p=mv-sheeva.git

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e2d1587be26..4298abaae15 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -89,7 +89,8 @@ struct khugepaged_scan {
 	struct list_head mm_head;
 	struct mm_slot *mm_slot;
 	unsigned long address;
-} khugepaged_scan = {
+};
+static struct khugepaged_scan khugepaged_scan = {
 	.mm_head = LIST_HEAD_INIT(khugepaged_scan.mm_head),
 };
 
@@ -829,7 +830,7 @@ static int do_huge_pmd_wp_page_fallback(struct mm_struct *mm,
 
 	for (i = 0; i < HPAGE_PMD_NR; i++) {
 		copy_user_highpage(pages[i], page + i,
-				   haddr + PAGE_SHIFT*i, vma);
+				   haddr + PAGE_SIZE * i, vma);
 		__SetPageUptodate(pages[i]);
 		cond_resched();
 	}
@@ -989,7 +990,7 @@ struct page *follow_trans_huge_pmd(struct mm_struct *mm,
 	page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT;
 	VM_BUG_ON(!PageCompound(page));
 	if (flags & FOLL_GET)
-		get_page(page);
+		get_page_foll(page);
 
 out:
 	return page;
@@ -1052,6 +1053,51 @@ int mincore_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 	return ret;
 }
 
+int move_huge_pmd(struct vm_area_struct *vma, struct vm_area_struct *new_vma,
+		  unsigned long old_addr,
+		  unsigned long new_addr, unsigned long old_end,
+		  pmd_t *old_pmd, pmd_t *new_pmd)
+{
+	int ret = 0;
+	pmd_t pmd;
+
+	struct mm_struct *mm = vma->vm_mm;
+
+	if ((old_addr & ~HPAGE_PMD_MASK) ||
+	    (new_addr & ~HPAGE_PMD_MASK) ||
+	    old_end - old_addr < HPAGE_PMD_SIZE ||
+	    (new_vma->vm_flags & VM_NOHUGEPAGE))
+		goto out;
+
+	/*
+	 * The destination pmd shouldn't be established, free_pgtables()
+	 * should have release it.
+	 */
+	if (WARN_ON(!pmd_none(*new_pmd))) {
+		VM_BUG_ON(pmd_trans_huge(*new_pmd));
+		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 {
+		spin_unlock(&mm->page_table_lock);
+	}
+out:
+	return ret;
+}
+
 int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 		unsigned long addr, pgprot_t newprot)
 {
@@ -1156,6 +1202,7 @@ static void __split_huge_page_refcount(struct page *page)
 	unsigned long head_index = page->index;
 	struct zone *zone = page_zone(page);
 	int zonestat;
+	int tail_count = 0;
 
 	/* prevent PageLRU to go away from under us, and freeze lru stats */
 	spin_lock_irq(&zone->lru_lock);
@@ -1164,11 +1211,27 @@ static void __split_huge_page_refcount(struct page *page)
 	for (i = 1; i < HPAGE_PMD_NR; i++) {
 		struct page *page_tail = page + i;
 
-		/* tail_page->_count cannot change */
-		atomic_sub(atomic_read(&page_tail->_count), &page->_count);
-		BUG_ON(page_count(page) <= 0);
-		atomic_add(page_mapcount(page) + 1, &page_tail->_count);
-		BUG_ON(atomic_read(&page_tail->_count) <= 0);
+		/* tail_page->_mapcount cannot change */
+		BUG_ON(page_mapcount(page_tail) < 0);
+		tail_count += page_mapcount(page_tail);
+		/* check for overflow */
+		BUG_ON(tail_count < 0);
+		BUG_ON(atomic_read(&page_tail->_count) != 0);
+		/*
+		 * tail_page->_count is zero and not changing from
+		 * under us. But get_page_unless_zero() may be running
+		 * from under us on the tail_page. If we used
+		 * atomic_set() below instead of atomic_add(), we
+		 * would then run atomic_set() concurrently with
+		 * get_page_unless_zero(), and atomic_set() is
+		 * implemented in C not using locked ops. spin_unlock
+		 * on x86 sometime uses locked ops because of PPro
+		 * errata 66, 92, so unless somebody can guarantee
+		 * atomic_set() here would be safe on all archs (and
+		 * not only on x86), it's safer to use atomic_add().
+		 */
+		atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1,
+			   &page_tail->_count);
 
 		/* after clearing PageTail the gup refcount can be released */
 		smp_mb();
@@ -1186,10 +1249,7 @@ static void __split_huge_page_refcount(struct page *page)
 				      (1L << PG_uptodate)));
 		page_tail->flags |= (1L << PG_dirty);
 
-		/*
-		 * 1) clear PageTail before overwriting first_page
-		 * 2) clear PageTail before clearing PageHead for VM_BUG_ON
-		 */
+		/* clear PageTail before overwriting first_page */
 		smp_wmb();
 
 		/*
@@ -1206,7 +1266,6 @@ static void __split_huge_page_refcount(struct page *page)
 		 * status is achieved setting a reserved bit in the
 		 * pmd, not by clearing the present bit.
 		*/
-		BUG_ON(page_mapcount(page_tail));
 		page_tail->_mapcount = page->_mapcount;
 
 		BUG_ON(page_tail->mapping);
@@ -1223,6 +1282,8 @@ static void __split_huge_page_refcount(struct page *page)
 
 		lru_add_page_tail(zone, page, page_tail);
 	}
+	atomic_sub(tail_count, &page->_count);
+	BUG_ON(atomic_read(&page->_count) <= 0);
 
 	__dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
 	__mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR);
@@ -1906,7 +1967,7 @@ static void collapse_huge_page(struct mm_struct *mm,
 	BUG_ON(!pmd_none(*pmd));
 	page_add_new_anon_rmap(new_page, vma, address);
 	set_pmd_at(mm, address, pmd, _pmd);
-	update_mmu_cache(vma, address, entry);
+	update_mmu_cache(vma, address, _pmd);
 	prepare_pmd_huge_pte(pgtable, mm);
 	mm->nr_ptes--;
 	spin_unlock(&mm->page_table_lock);
@@ -2024,6 +2085,8 @@ static void collect_mm_slot(struct mm_slot *mm_slot)
 
 static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
 					    struct page **hpage)
+	__releases(&khugepaged_mm_lock)
+	__acquires(&khugepaged_mm_lock)
 {
 	struct mm_slot *mm_slot;
 	struct mm_struct *mm;