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thp: madvise(MADV_NOHUGEPAGE)

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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>
This commit is contained in:
Andrea Arcangeli
2011-01-13 15:47:17 -08:00
committed by Linus Torvalds
parent 1ddd6db43a
commit a664b2d855
5 changed files with 46 additions and 21 deletions
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41
mm/huge_memory.c
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@@ -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 @@ out:
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;
}