This is a note to let you know that I've just added the patch titled
mm: setup pageblock_order before it's used by sparsemem
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-setup-pageblock_order-before-it-s-used-by-sparsemem.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ca57df79d4f64e1a4886606af4289d40636189c5 Mon Sep 17 00:00:00 2001
From: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Date: Tue, 31 Jul 2012 16:43:19 -0700
Subject: mm: setup pageblock_order before it's used by sparsemem
From: Xishi Qiu <qiuxishi@xxxxxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Jiang Liu <liuj97@xxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Keping Chen <chenkeping@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/internal.h | 2 ++
mm/page_alloc.c | 4 ++--
mm/sparse.c | 3 +++
3 files changed, 7 insertions(+), 2 deletions(-)
--- 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);
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4255,7 +4255,7 @@ static inline void setup_usemap(struct p
#ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
/* 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;
@@ -4283,7 +4283,7 @@ static inline void __init set_pageblock_
* 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)
{
}
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -486,6 +486,9 @@ void __init sparse_init(void)
struct page **map_map;
#endif
+ /* 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)
Patches currently in stable-queue which might be from qiuxishi@xxxxxxxxxx are
queue-3.4/mm-setup-pageblock_order-before-it-s-used-by-sparsemem.patch
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