From c79fb75e5a514a5a35f22c229042aa29f4237e3a Mon Sep 17 00:00:00 2001 From: Adam Litke Date: Wed, 14 Nov 2007 16:59:38 -0800 Subject: hugetlb: fix quota management for private mappings The hugetlbfs quota management system was never taught to handle MAP_PRIVATE mappings when that support was added. Currently, quota is debited at page instantiation and credited at file truncation. This approach works correctly for shared pages but is incomplete for private pages. In addition to hugetlb_no_page(), private pages can be instantiated by hugetlb_cow(); but this function does not respect quotas. Private huge pages are treated very much like normal, anonymous pages. They are not "backed" by the hugetlbfs file and are not stored in the mapping's radix tree. This means that private pages are invisible to truncate_hugepages() so that function will not credit the quota. This patch (based on a prototype provided by Ken Chen) moves quota crediting for all pages into free_huge_page(). page->private is used to store a pointer to the mapping to which this page belongs. This is used to credit quota on the appropriate hugetlbfs instance. Signed-off-by: Adam Litke Cc: Ken Chen Cc: Ken Chen Cc: Andy Whitcroft Cc: Dave Hansen Cc: David Gibson Cc: William Lee Irwin III Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'mm/hugetlb.c') diff --git a/mm/hugetlb.c b/mm/hugetlb.c index f43b3dca12b..3992bd5120e 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -116,7 +116,9 @@ static void update_and_free_page(struct page *page) static void free_huge_page(struct page *page) { int nid = page_to_nid(page); + struct address_space *mapping; + mapping = (struct address_space *) page_private(page); BUG_ON(page_count(page)); INIT_LIST_HEAD(&page->lru); @@ -129,6 +131,9 @@ static void free_huge_page(struct page *page) enqueue_huge_page(page); } spin_unlock(&hugetlb_lock); + if (mapping) + hugetlb_put_quota(mapping); + set_page_private(page, 0); } /* @@ -388,8 +393,10 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, page = alloc_huge_page_shared(vma, addr); else page = alloc_huge_page_private(vma, addr); - if (page) + if (page) { set_page_refcounted(page); + set_page_private(page, (unsigned long) vma->vm_file->f_mapping); + } return page; } @@ -730,6 +737,8 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, set_huge_ptep_writable(vma, address, ptep); return 0; } + if (hugetlb_get_quota(vma->vm_file->f_mapping)) + return VM_FAULT_SIGBUS; page_cache_get(old_page); new_page = alloc_huge_page(vma, address); @@ -796,7 +805,6 @@ retry: err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); if (err) { put_page(page); - hugetlb_put_quota(mapping); if (err == -EEXIST) goto retry; goto out; @@ -830,7 +838,6 @@ out: backout: spin_unlock(&mm->page_table_lock); - hugetlb_put_quota(mapping); unlock_page(page); put_page(page); goto out; -- cgit v1.2.3