thp: don't allow transparent hugepage support without PSE

Archs implementing Transparent Hugepage Support must implement a function called has_transparent_hugepage to be sure the virtual or physical CPU supports Transparent Hugepages. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
git-mirror · Jan 14, 2011 · 4b7167b · 4b7167b
1 parent 94fcc58
commit 4b7167b
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diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
@@ -160,6 +160,11 @@ static inline int pmd_trans_huge(pmd_t pmd)
 {
 	return pmd_val(pmd) & _PAGE_PSE;
 }
+
+static inline int has_transparent_hugepage(void)
+{
+	return cpu_has_pse;
+}
 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 
 static inline pte_t pte_set_flags(pte_t pte, pteval_t set)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
@@ -487,7 +487,15 @@ static int __init hugepage_init(void)
 	int err;
 #ifdef CONFIG_SYSFS
 	static struct kobject *hugepage_kobj;
+#endif
 
+	err = -EINVAL;
+	if (!has_transparent_hugepage()) {
+		transparent_hugepage_flags = 0;
+		goto out;
+	}
+
+#ifdef CONFIG_SYSFS
 	err = -ENOMEM;
 	hugepage_kobj = kobject_create_and_add("transparent_hugepage", mm_kobj);
 	if (unlikely(!hugepage_kobj)) {