thp: madvise(MADV_NOHUGEPAGE)
Add madvise MADV_NOHUGEPAGE to mark regions that are not important to be
hugepage backed. Return -EINVAL if the vma is not of an anonymous type,
or the feature isn't built into the kernel. Never silently return
success.
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>
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f4f6041..fce667c0 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -16,6 +16,7 @@
#include <linux/kthread.h>
#include <linux/khugepaged.h>
#include <linux/freezer.h>
+#include <linux/mman.h>
#include <asm/tlb.h>
#include <asm/pgalloc.h>
#include "internal.h"
@@ -1388,18 +1389,36 @@
return ret;
}
-int hugepage_madvise(unsigned long *vm_flags)
+int hugepage_madvise(unsigned long *vm_flags, int advice)
{
- /*
- * Be somewhat over-protective like KSM for now!
- */
- if (*vm_flags & (VM_HUGEPAGE | VM_SHARED | VM_MAYSHARE |
- VM_PFNMAP | VM_IO | VM_DONTEXPAND |
- VM_RESERVED | VM_HUGETLB | VM_INSERTPAGE |
- VM_MIXEDMAP | VM_SAO))
- return -EINVAL;
-
- *vm_flags |= VM_HUGEPAGE;
+ switch (advice) {
+ case MADV_HUGEPAGE:
+ /*
+ * Be somewhat over-protective like KSM for now!
+ */
+ if (*vm_flags & (VM_HUGEPAGE |
+ VM_SHARED | VM_MAYSHARE |
+ VM_PFNMAP | VM_IO | VM_DONTEXPAND |
+ VM_RESERVED | VM_HUGETLB | VM_INSERTPAGE |
+ VM_MIXEDMAP | VM_SAO))
+ return -EINVAL;
+ *vm_flags &= ~VM_NOHUGEPAGE;
+ *vm_flags |= VM_HUGEPAGE;
+ break;
+ case MADV_NOHUGEPAGE:
+ /*
+ * Be somewhat over-protective like KSM for now!
+ */
+ if (*vm_flags & (VM_NOHUGEPAGE |
+ VM_SHARED | VM_MAYSHARE |
+ VM_PFNMAP | VM_IO | VM_DONTEXPAND |
+ VM_RESERVED | VM_HUGETLB | VM_INSERTPAGE |
+ VM_MIXEDMAP | VM_SAO))
+ return -EINVAL;
+ *vm_flags &= ~VM_HUGEPAGE;
+ *vm_flags |= VM_NOHUGEPAGE;
+ break;
+ }
return 0;
}
diff --git a/mm/madvise.c b/mm/madvise.c
index ecde40a..bbac126 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -72,7 +72,8 @@
goto out;
break;
case MADV_HUGEPAGE:
- error = hugepage_madvise(&new_flags);
+ case MADV_NOHUGEPAGE:
+ error = hugepage_madvise(&new_flags, behavior);
if (error)
goto out;
break;
@@ -290,6 +291,7 @@
#endif
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
case MADV_HUGEPAGE:
+ case MADV_NOHUGEPAGE:
#endif
return 1;