Re: [PATCH 1/1] page_alloc.c: remove argument to pageblock_default_order
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2012-05-03 23:37:54
Also in:
linux-mm, lkml
On Thu, 3 May 2012 22:45:12 +0530 rajman mekaco [off-list ref] wrote:
quoted hunk
When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not defined, then pageblock_default_order has an argument to it. However, free_area_init_core will call it without any argument anyway. Remove the argument to pageblock_default_order when CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not defined. Signed-off-by: rajman mekaco <redacted> --- mm/page_alloc.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)diff --git a/mm/page_alloc.c b/mm/page_alloc.c index a712fb9..4b95412 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c@@ -4274,7 +4274,7 @@ static inline void __init set_pageblock_order(unsigned int order) * at compile-time. See include/linux/pageblock-flags.h for the values of * pageblock_order based on the kernel config */ -static inline int pageblock_default_order(unsigned int order) +static inline int pageblock_default_order(void) { return MAX_ORDER-1; }
Interesting. It has been that way since at least 3.1.
It didn't break the build because pageblock_default_order() is only
ever invoked by set_pageblock_order(), with:
set_pageblock_order(pageblock_default_order());
and set_pageblock_order() is a macro:
#define set_pageblock_order(x) do {} while (0)
There's yet another reason not to use macros, dammit - they hide bugs.
Mel, can you have a think about this please? Can we just kill off
pageblock_default_order() and fold its guts into
set_pageblock_order(void)? Only ia64 and powerpc can define
CONFIG_HUGETLB_PAGE_SIZE_VARIABLE.
--- a/mm/page_alloc.c~a
+++ a/mm/page_alloc.c@@ -4300,25 +4300,24 @@ static inline void setup_usemap(struct p #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE -/* Return a sensible default order for the pageblock size. */ -static inline int pageblock_default_order(void) -{ - if (HPAGE_SHIFT > PAGE_SHIFT) - return HUGETLB_PAGE_ORDER; - - return MAX_ORDER-1; -} - /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */ -static inline void __init set_pageblock_order(unsigned int order) +static inline void __init set_pageblock_order(void) { + unsigned int order; + /* Check that pageblock_nr_pages has not already been setup */ if (pageblock_order) return; + if (HPAGE_SHIFT > PAGE_SHIFT) + order = HUGETLB_PAGE_ORDER; + else + order = MAX_ORDER - 1; + /* * Assume the largest contiguous order of interest is a huge page. - * This value may be variable depending on boot parameters on IA64 + * This value may be variable depending on boot parameters on IA64 and + * powerpc. */ pageblock_order = order; }
@@ -4326,15 +4325,13 @@ static inline void __init set_pageblock_ /* * When CONFIG_HUGETLB_PAGE_SIZE_VARIABLE is not set, set_pageblock_order() - * and pageblock_default_order() are unused as pageblock_order is set - * at compile-time. See include/linux/pageblock-flags.h for the values of - * pageblock_order based on the kernel config + * is unused as pageblock_order is set at compile-time. See + * include/linux/pageblock-flags.h for the values of pageblock_order based on + * the kernel config */ -static inline int pageblock_default_order(unsigned int order) +static inline void set_pageblock_order(void) { - return MAX_ORDER-1; } -#define set_pageblock_order(x) do {} while (0) #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
@@ -4422,7 +4419,7 @@ static void __paginginit free_area_init_ if (!size) continue; - set_pageblock_order(pageblock_default_order()); + set_pageblock_order(); setup_usemap(pgdat, zone, size); ret = init_currently_empty_zone(zone, zone_start_pfn, size, MEMMAP_EARLY);
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