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authorNick Piggin <npiggin@suse.de>2006-03-22 00:08:08 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-22 07:53:58 -0800
commita482289d46587ffcda4c85aab109fb74910d7a48 (patch)
tree351dc5d9c09a4fe3d122c2157a298852ac8a821c /mm/hugetlb.c
parent545b1ea9bfa5a8ca9af33d63144bd4f2faaea8dd (diff)
downloadop-kernel-dev-a482289d46587ffcda4c85aab109fb74910d7a48.zip
op-kernel-dev-a482289d46587ffcda4c85aab109fb74910d7a48.tar.gz
[PATCH] hugepage allocator cleanup
Insert "fresh" huge pages into the hugepage allocator by the same means as they are freed back into it. This reduces code size and allows enqueue_huge_page to be inlined into the hugepage free fastpath. Eliminate occurances of hugepages on the free list with non-zero refcount. This can allow stricter refcount checks in future. Also required for lockless pagecache. Signed-off-by: Nick Piggin <npiggin@suse.de> "This patch also eliminates a leak "cleaned up" by re-clobbering the refcount on every allocation from the hugepage freelists. With respect to the lockless pagecache, the crucial aspect is to eliminate unconditional set_page_count() to 0 on pages with potentially nonzero refcounts, though closer inspection suggests the assignments removed are entirely spurious." Acked-by: William Irwin <wli@holomorphy.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r--mm/hugetlb.c24
1 files changed, 8 insertions, 16 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 5087077..39d49ec 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -64,7 +64,7 @@ static struct page *dequeue_huge_page(struct vm_area_struct *vma,
return page;
}
-static struct page *alloc_fresh_huge_page(void)
+static int alloc_fresh_huge_page(void)
{
static int nid = 0;
struct page *page;
@@ -72,12 +72,15 @@ static struct page *alloc_fresh_huge_page(void)
HUGETLB_PAGE_ORDER);
nid = (nid + 1) % num_online_nodes();
if (page) {
+ page[1].lru.next = (void *)free_huge_page; /* dtor */
spin_lock(&hugetlb_lock);
nr_huge_pages++;
nr_huge_pages_node[page_to_nid(page)]++;
spin_unlock(&hugetlb_lock);
+ put_page(page); /* free it into the hugepage allocator */
+ return 1;
}
- return page;
+ return 0;
}
void free_huge_page(struct page *page)
@@ -85,7 +88,6 @@ void free_huge_page(struct page *page)
BUG_ON(page_count(page));
INIT_LIST_HEAD(&page->lru);
- page[1].lru.next = NULL; /* reset dtor */
spin_lock(&hugetlb_lock);
enqueue_huge_page(page);
@@ -105,7 +107,6 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, unsigned long addr)
}
spin_unlock(&hugetlb_lock);
set_page_count(page, 1);
- page[1].lru.next = (void *)free_huge_page; /* set dtor */
for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i)
clear_user_highpage(&page[i], addr);
return page;
@@ -114,7 +115,6 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, unsigned long addr)
static int __init hugetlb_init(void)
{
unsigned long i;
- struct page *page;
if (HPAGE_SHIFT == 0)
return 0;
@@ -123,12 +123,8 @@ static int __init hugetlb_init(void)
INIT_LIST_HEAD(&hugepage_freelists[i]);
for (i = 0; i < max_huge_pages; ++i) {
- page = alloc_fresh_huge_page();
- if (!page)
+ if (!alloc_fresh_huge_page())
break;
- spin_lock(&hugetlb_lock);
- enqueue_huge_page(page);
- spin_unlock(&hugetlb_lock);
}
max_huge_pages = free_huge_pages = nr_huge_pages = i;
printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages);
@@ -154,8 +150,8 @@ static void update_and_free_page(struct page *page)
page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced |
1 << PG_dirty | 1 << PG_active | 1 << PG_reserved |
1 << PG_private | 1<< PG_writeback);
- set_page_count(&page[i], 0);
}
+ page[1].lru.next = NULL;
set_page_count(page, 1);
__free_pages(page, HUGETLB_PAGE_ORDER);
}
@@ -188,12 +184,8 @@ static inline void try_to_free_low(unsigned long count)
static unsigned long set_max_huge_pages(unsigned long count)
{
while (count > nr_huge_pages) {
- struct page *page = alloc_fresh_huge_page();
- if (!page)
+ if (!alloc_fresh_huge_page())
return nr_huge_pages;
- spin_lock(&hugetlb_lock);
- enqueue_huge_page(page);
- spin_unlock(&hugetlb_lock);
}
if (count >= nr_huge_pages)
return nr_huge_pages;
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