Subject: + mm-fix-negative-left-shift-count-when-page_shift-20.patch added to -mm tree
To: uulinux@xxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 24 Jul 2013 12:51:49 -0700
The patch titled
Subject: mm: fix negative left shift count when PAGE_SHIFT > 20
has been added to the -mm tree. Its filename is
mm-fix-negative-left-shift-count-when-page_shift-20.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-fix-negative-left-shift-count-when-page_shift-20.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-fix-negative-left-shift-count-when-page_shift-20.patch
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------------------------------------------------------
From: Jerry Zhou <uulinux@xxxxxxxxx>
Subject: mm: fix negative left shift count when PAGE_SHIFT > 20
When PAGE_SHIFT > 20, the result of "20 - PAGE_SHIFT" is negative. The
previous calculating here will generate an unexpected result. In
addition, if PAGE_SIZE >= 1MB, The memory size of "numentries" was
already integral multiple of 1MB.
Signed-off-by: Jerry Zhou <uulinux@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff -puN mm/page_alloc.c~mm-fix-negative-left-shift-count-when-page_shift-20 mm/page_alloc.c
--- a/mm/page_alloc.c~mm-fix-negative-left-shift-count-when-page_shift-20
+++ a/mm/page_alloc.c
@@ -5745,9 +5745,10 @@ void *__init alloc_large_system_hash(con
if (!numentries) {
/* round applicable memory size up to nearest megabyte */
numentries = nr_kernel_pages;
- numentries += (1UL << (20 - PAGE_SHIFT)) - 1;
- numentries >>= 20 - PAGE_SHIFT;
- numentries <<= 20 - PAGE_SHIFT;
+
+ /* It isn't necessary when PAGE_SIZE >= 1MB */
+ if (PAGE_SHIFT < 20)
+ numentries = round_up(numentries, (1<<20)/PAGE_SIZE);
/* limit to 1 bucket per 2^scale bytes of low memory */
if (scale > PAGE_SHIFT)
_
Patches currently in -mm which might be from uulinux@xxxxxxxxx are
mm-fix-negative-left-shift-count-when-page_shift-20.patch
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