Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753111Ab2F3JKM (ORCPT ); Sat, 30 Jun 2012 05:10:12 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:57732 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752516Ab2F3JKK (ORCPT ); Sat, 30 Jun 2012 05:10:10 -0400 From: Jiang Liu To: Andrew Morton , Mel Gorman , Tony Luck , Yinghai Lu CC: Xishi Qiu , KAMEZAWA Hiroyuki , KOSAKI Motohiro , David Rientjes , Minchan Kim , Keping Chen , , , , Jiang Liu Subject: [PATCH] mm: setup pageblock_order before it's used by sparse Date: Sat, 30 Jun 2012 17:07:54 +0800 Message-ID: <1341047274-5616-1-git-send-email-jiang.liu@huawei.com> X-Mailer: git-send-email 1.7.8.msysgit.0 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.108.108.229] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2936 Lines: 89 From: Xishi Qiu 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 Signed-off-by: Jiang Liu --- 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/