From: Nick Piggin 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 "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 Signed-off-by: Andrew Morton --- mm/hugetlb.c | 24 ++++++++---------------- 1 files changed, 8 insertions(+), 16 deletions(-) diff -puN mm/hugetlb.c~hugepage-allocator-cleanup mm/hugetlb.c --- devel/mm/hugetlb.c~hugepage-allocator-cleanup 2006-02-12 16:28:51.000000000 -0800 +++ devel-akpm/mm/hugetlb.c 2006-02-12 16:38:31.000000000 -0800 @@ -64,7 +64,7 @@ static struct page *dequeue_huge_page(st 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_pag 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_a } 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_a 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[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(unsig 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; _