During boot, we populate the page lists by using the page freeing
mechanism on every individual page. Unfortunately, this is very
inefficient because the memory manager spends a lot of time coalescing
pairs of adjacent free pages into bigger blocks.
Rather than adding a single order 0 page at a time, we can take
advantage of the fact that we know that all the pages are available and
free up big blocks of pages at a time instead.
Signed-off-by: Chirantan Ekbote <chirantan@xxxxxxxxxxxx>
---
arch/arm/mm/init.c | 19 +++++++++++++++++--
include/linux/gfp.h | 1 +
mm/internal.h | 1 -
3 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 97c293e..c7fc2d8 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -22,6 +22,7 @@
#include <linux/memblock.h>
#include <linux/dma-contiguous.h>
#include <linux/sizes.h>
+#include <linux/bitops.h>
#include <asm/mach-types.h>
#include <asm/memblock.h>
@@ -469,8 +470,22 @@ static void __init free_unused_memmap(struct meminfo *mi)
#ifdef CONFIG_HIGHMEM
static inline void free_area_high(unsigned long pfn, unsigned long end)
{
- for (; pfn < end; pfn++)
- free_highmem_page(pfn_to_page(pfn));
+ while (pfn < end) {
+ struct page *page = pfn_to_page(pfn);
+ unsigned long order = min(__ffs(pfn), MAX_ORDER - 1);
+ unsigned long nr_pages = 1 << order;
+ unsigned long rem = end - pfn;
+
+ if (nr_pages > rem) {
+ order = __fls(rem);
+ nr_pages = 1 << order;
+ }
+
+ __free_pages_bootmem(page, order);
+ totalram_pages += nr_pages;
+ totalhigh_pages += nr_pages;
+ pfn += nr_pages;
+ }
}
#endif
diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 39b81dc..a63d666 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -367,6 +367,7 @@ void *alloc_pages_exact_nid(int nid, size_t size, gfp_t gfp_mask);
#define __get_dma_pages(gfp_mask, order) \
__get_free_pages((gfp_mask) | GFP_DMA, (order))
+extern void __free_pages_bootmem(struct page *page, unsigned int order);
extern void __free_pages(struct page *page, unsigned int order);
extern void free_pages(unsigned long addr, unsigned int order);
extern void free_hot_cold_page(struct page *page, int cold);
diff --git a/mm/internal.h b/mm/internal.h
index 29e1e76..d2b8738 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -93,7 +93,6 @@ extern pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address);
/*
* in mm/page_alloc.c
*/
-extern void __free_pages_bootmem(struct page *page, unsigned int order);
extern void prep_compound_page(struct page *page, unsigned long order);
#ifdef CONFIG_MEMORY_FAILURE
extern bool is_free_buddy_page(struct page *page);
--
1.9.1.423.g4596e3a
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