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authorXishi Qiu <qiuxishi@huawei.com>2012-07-31 16:43:19 -0700
committerBen Hutchings <ben@decadent.org.uk>2012-08-10 00:25:09 +0100
commit3927df7e5035769cea8c6646ebd28d9fdab86057 (patch)
parent27c4b68bb5e9b5dd81ae5e156e4094643d127608 (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>
3 files changed, 7 insertions, 2 deletions
diff --git a/mm/internal.h b/mm/internal.h
index 2189af491783..0c26b5e6d41d 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);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 63a4e1d95ec9..6e51bf054b4a 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4282,7 +4282,7 @@ static inline void setup_usemap(struct pglist_data *pgdat,
/* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
-static inline void __init set_pageblock_order(void)
+void __init set_pageblock_order(void)
unsigned int order;
@@ -4310,7 +4310,7 @@ static inline void __init set_pageblock_order(void)
* include/linux/pageblock-flags.h for the values of pageblock_order based on
* the kernel config
-static inline void set_pageblock_order(void)
+void __init set_pageblock_order(void)
diff --git a/mm/sparse.c b/mm/sparse.c
index a8bc7d364deb..bf7d3cc0cc1a 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -486,6 +486,9 @@ void __init sparse_init(void)
struct page **map_map;
+ /* Setup pageblock_order for HUGETLB_PAGE_SIZE_VARIABLE */
+ set_pageblock_order();
* map is using big page (aka 2M in x86 64 bit)
* usemap is less one page (aka 24 bytes)