Re: [PATCH] Fix for hugetlb-add-map_hugetlb-for-mmaping-pseudo-anonymous-huge-page-regions.patchin -mm
From: Hugh Dickins
Date: Tue Sep 15 2009 - 16:54:09 EST
On 2009年9月15日, Eric B Munson wrote:
>
Resending because this seems to have fallen between the cracks.
Yes, indeed. I think it isn't quite what Arnd was suggesting, but I
agree with you that we might as well go for 0x080000 (so that even Alpha
can be just a cut-and-paste job from asm-generic), and right now it's
more important to finalize the number than what file it appears in.
Acked-by: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
>
>
The patch
>
hugetlb-add-map_hugetlb-for-mmaping-pseudo-anonymous-huge-page-regions.patch
>
used the value 0x40 for MAP_HUGETLB which is the same value used for
>
various other flags on some architectures. This collision causes
>
unexpected use of huge pages in the best case and mmap to fail with
>
ENOMEM or ENOSYS in the worst. This patch changes the value for
>
MAP_HUGETLB to a value that is not currently used on any arch.
>
>
This patch should be considered a fix to
>
hugetlb-add-map_hugetlb-for-mmaping-pseudo-anonymous-huge-page-regions.patch.
>
>
Reported-by: Hugh Dickins <hugh.dickins@xxxxxxxxxxxxx>
>
Signed-off-by: Eric B Munson <ebmunson@xxxxxxxxxx>
>
---
>
include/asm-generic/mman-common.h | 2 +-
>
1 files changed, 1 insertions(+), 1 deletions(-)
>
>
diff --git a/include/asm-generic/mman-common.h b/include/asm-generic/mman-common.h
>
index 12f5982..e6adb68 100644
>
--- a/include/asm-generic/mman-common.h
>
+++ b/include/asm-generic/mman-common.h
>
@@ -19,7 +19,7 @@
>
#define MAP_TYPE 0x0f /* Mask for type of mapping */
>
#define MAP_FIXED 0x10 /* Interpret addr exactly */
>
#define MAP_ANONYMOUS 0x20 /* don't use a file */
>
-#define MAP_HUGETLB 0x40 /* create a huge page mapping */
>
+#define MAP_HUGETLB 0x080000 /* create a huge page mapping */
>
>
#define MS_ASYNC 1 /* sync memory asynchronously */
>
#define MS_INVALIDATE 2 /* invalidate the caches */
>
--
>
1.6.3.2
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