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[PATCH] mm: cleanup bootmem
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The bootmem code added to page_alloc.c duplicated some page freeing code
that it really doesn't need to because it is not so performance critical.

While we're here, make prefetching work properly by actually prefetching
the page we're about to use before prefetching ahead to the next one (ie.
get the most important transaction started first).  Also prefetch just a
single page ahead rather than leaving a gap of 16.

Jack Steiner reported no problems with SGI's ia64 simulator.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Nick Piggin authored and Linus Torvalds committed Mar 22, 2006
1 parent 9d41415 commit 545b1ea
Showing 1 changed file with 7 additions and 13 deletions.
20 changes: 7 additions & 13 deletions mm/page_alloc.c
Original file line number Diff line number Diff line change
Expand Up @@ -55,7 +55,6 @@ unsigned long totalhigh_pages __read_mostly;
long nr_swap_pages;
int percpu_pagelist_fraction;

static void fastcall free_hot_cold_page(struct page *page, int cold);
static void __free_pages_ok(struct page *page, unsigned int order);

/*
Expand Down Expand Up @@ -448,28 +447,23 @@ void fastcall __init __free_pages_bootmem(struct page *page, unsigned int order)
if (order == 0) {
__ClearPageReserved(page);
set_page_count(page, 0);

free_hot_cold_page(page, 0);
set_page_refs(page, 0);
__free_page(page);
} else {
LIST_HEAD(list);
int loop;

prefetchw(page);
for (loop = 0; loop < BITS_PER_LONG; loop++) {
struct page *p = &page[loop];

if (loop + 16 < BITS_PER_LONG)
prefetchw(p + 16);
if (loop + 1 < BITS_PER_LONG)
prefetchw(p + 1);
__ClearPageReserved(p);
set_page_count(p, 0);
}

arch_free_page(page, order);

mod_page_state(pgfree, 1 << order);

list_add(&page->lru, &list);
kernel_map_pages(page, 1 << order, 0);
free_pages_bulk(page_zone(page), 1, &list, order);
set_page_refs(page, order);
__free_pages(page, order);
}
}

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