linux-mm.kvack.org archive mirror
 help / color / mirror / Atom feed
From: Jiang Liu <jiang.liu@huawei.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Mel Gorman <mgorman@suse.de>, Tony Luck <tony.luck@intel.com>,
	Yinghai Lu <yinghai@kernel.org>
Cc: Xishi Qiu <qiuxishi@huawei.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	David Rientjes <rientjes@google.com>,
	Minchan Kim <minchan@kernel.org>,
	Keping Chen <chenkeping@huawei.com>,
	linux-mm@kvack.org, stable@vger.kernel.org,
	linux-kernel@vger.kernel.org, Jiang Liu <liuj97@gmail.com>
Subject: [PATCH] mm: setup pageblock_order before it's used by sparse
Date: Sat, 30 Jun 2012 17:07:54 +0800	[thread overview]
Message-ID: <1341047274-5616-1-git-send-email-jiang.liu@huawei.com> (raw)

From: Xishi Qiu <qiuxishi@huawei.com>

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>
---
 mm/internal.h   |    2 ++
 mm/page_alloc.c |    4 ++--
 mm/sparse.c     |    3 +++
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/mm/internal.h b/mm/internal.h
index 2ba87fb..8052379 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -347,3 +347,5 @@ extern u32 hwpoison_filter_enable;
 extern unsigned long vm_mmap_pgoff(struct file *, unsigned long,
         unsigned long, unsigned long,
         unsigned long, unsigned long);
+
+extern void set_pageblock_order(void);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 4403009..f38509b 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4301,7 +4301,7 @@ static inline void setup_usemap(struct pglist_data *pgdat,
 #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;
 
@@ -4329,7 +4329,7 @@ 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 fca2ab5..3a3af73 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -485,6 +485,9 @@ 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)
-- 
1.7.1


--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

             reply	other threads:[~2012-06-30  9:10 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-06-30  9:07 Jiang Liu [this message]
2012-06-30 20:15 ` [PATCH] mm: setup pageblock_order before it's used by sparse Yinghai Lu
2012-07-02  2:01   ` Jiang Liu
2012-07-02 20:43     ` Yinghai Lu
2012-07-03  2:54       ` Jiang Liu
2012-07-03  3:25         ` Yinghai Lu
2012-07-03  3:29           ` Jiang Liu
2012-07-18  7:17             ` Benjamin Herrenschmidt
2012-07-18  7:15           ` Benjamin Herrenschmidt
2012-06-30 20:46 ` Greg KH
2012-07-02 12:41 ` Mel Gorman
2012-07-03 21:07 ` Andrew Morton
2012-07-04  1:40   ` Jiang Liu
2012-07-04  9:20     ` Mel Gorman
2012-07-06  1:00       ` Yinghai Lu
2012-07-06  1:24         ` Benjamin Herrenschmidt
2012-07-17  9:31           ` Jiang Liu
2012-07-18  7:01             ` Benjamin Herrenschmidt

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1341047274-5616-1-git-send-email-jiang.liu@huawei.com \
    --to=jiang.liu@huawei.com \
    --cc=akpm@linux-foundation.org \
    --cc=chenkeping@huawei.com \
    --cc=kamezawa.hiroyu@jp.fujitsu.com \
    --cc=kosaki.motohiro@jp.fujitsu.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=liuj97@gmail.com \
    --cc=mgorman@suse.de \
    --cc=minchan@kernel.org \
    --cc=qiuxishi@huawei.com \
    --cc=rientjes@google.com \
    --cc=stable@vger.kernel.org \
    --cc=tony.luck@intel.com \
    --cc=yinghai@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).