diff options
| author | Xishi Qiu <qiuxishi@huawei.com> | 2012-07-31 16:43:19 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2012-08-10 00:25:09 +0100 |
| commit | 3927df7e5035769cea8c6646ebd28d9fdab86057 (patch) | |
| tree | c7824fba461b2e0ea6279dfb92f36cf6aabcfa6b /mm/internal.h | |
| parent | 27c4b68bb5e9b5dd81ae5e156e4094643d127608 (diff) | |
mm: setup pageblock_order before it's used by sparsemem
commit ca57df79d4f64e1a4886606af4289d40636189c5 upstream.
On architectures with CONFIG_HUGETLB_PAGE_SIZE_VARIABLE set, such as
Itanium, pageblock_order is a variable with default value of 0. It's set
to the right value by set_pageblock_order() in function
free_area_init_core().
But pageblock_order may be used by sparse_init() before free_area_init_core()
is called along path:
sparse_init()
->sparse_early_usemaps_alloc_node()
->usemap_size()
->SECTION_BLOCKFLAGS_BITS
->((1UL << (PFN_SECTION_SHIFT - pageblock_order)) *
NR_PAGEBLOCK_BITS)
The uninitialized pageblock_size will cause memory wasting because
usemap_size() returns a much bigger value then it's really needed.
For example, on an Itanium platform,
sparse_init() pageblock_order=0 usemap_size=24576
free_area_init_core() before pageblock_order=0, usemap_size=24576
free_area_init_core() after pageblock_order=12, usemap_size=8
That means 24K memory has been wasted for each section, so fix it by calling
set_pageblock_order() from sparse_init().
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Jiang Liu <liuj97@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Keping Chen <chenkeping@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'mm/internal.h')
| -rw-r--r-- | mm/internal.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/internal.h b/mm/internal.h index 2189af49178..0c26b5e6d41 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -309,3 +309,5 @@ extern u64 hwpoison_filter_flags_mask; extern u64 hwpoison_filter_flags_value; extern u64 hwpoison_filter_memcg; extern u32 hwpoison_filter_enable; + +extern void set_pageblock_order(void); |