diff options
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 56 |
1 files changed, 45 insertions, 11 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 89e6286a7f57..74c1b6b0b37b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -71,7 +71,25 @@ static void enqueue_huge_page(struct page *page) free_huge_pages_node[nid]++; } -static struct page *dequeue_huge_page(struct vm_area_struct *vma, +static struct page *dequeue_huge_page(void) +{ + int nid; + struct page *page = NULL; + + for (nid = 0; nid < MAX_NUMNODES; ++nid) { + if (!list_empty(&hugepage_freelists[nid])) { + page = list_entry(hugepage_freelists[nid].next, + struct page, lru); + list_del(&page->lru); + free_huge_pages--; + free_huge_pages_node[nid]--; + break; + } + } + return page; +} + +static struct page *dequeue_huge_page_vma(struct vm_area_struct *vma, unsigned long address) { int nid; @@ -268,6 +286,12 @@ static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma, spin_lock(&hugetlb_lock); if (page) { + /* + * This page is now managed by the hugetlb allocator and has + * no users -- drop the buddy allocator's reference. + */ + put_page_testzero(page); + VM_BUG_ON(page_count(page)); nid = page_to_nid(page); set_compound_page_dtor(page, free_huge_page); /* @@ -296,8 +320,10 @@ static int gather_surplus_pages(int delta) int needed, allocated; needed = (resv_huge_pages + delta) - free_huge_pages; - if (needed <= 0) + if (needed <= 0) { + resv_huge_pages += delta; return 0; + } allocated = 0; INIT_LIST_HEAD(&surplus_list); @@ -335,9 +361,12 @@ retry: * The surplus_list now contains _at_least_ the number of extra pages * needed to accomodate the reservation. Add the appropriate number * of pages to the hugetlb pool and free the extras back to the buddy - * allocator. + * allocator. Commit the entire reservation here to prevent another + * process from stealing the pages as they are added to the pool but + * before they are reserved. */ needed += allocated; + resv_huge_pages += delta; ret = 0; free: list_for_each_entry_safe(page, tmp, &surplus_list, lru) { @@ -346,13 +375,14 @@ free: enqueue_huge_page(page); else { /* - * Decrement the refcount and free the page using its - * destructor. This must be done with hugetlb_lock + * The page has a reference count of zero already, so + * call free_huge_page directly instead of using + * put_page. This must be done with hugetlb_lock * unlocked which is safe because free_huge_page takes * hugetlb_lock before deciding how to free the page. */ spin_unlock(&hugetlb_lock); - put_page(page); + free_huge_page(page); spin_lock(&hugetlb_lock); } } @@ -371,6 +401,9 @@ static void return_unused_surplus_pages(unsigned long unused_resv_pages) struct page *page; unsigned long nr_pages; + /* Uncommit the reservation */ + resv_huge_pages -= unused_resv_pages; + nr_pages = min(unused_resv_pages, surplus_huge_pages); while (nr_pages) { @@ -402,7 +435,7 @@ static struct page *alloc_huge_page_shared(struct vm_area_struct *vma, struct page *page; spin_lock(&hugetlb_lock); - page = dequeue_huge_page(vma, addr); + page = dequeue_huge_page_vma(vma, addr); spin_unlock(&hugetlb_lock); return page ? page : ERR_PTR(-VM_FAULT_OOM); } @@ -417,7 +450,7 @@ static struct page *alloc_huge_page_private(struct vm_area_struct *vma, spin_lock(&hugetlb_lock); if (free_huge_pages > resv_huge_pages) - page = dequeue_huge_page(vma, addr); + page = dequeue_huge_page_vma(vma, addr); spin_unlock(&hugetlb_lock); if (!page) { page = alloc_buddy_huge_page(vma, addr); @@ -570,7 +603,7 @@ static unsigned long set_max_huge_pages(unsigned long count) min_count = max(count, min_count); try_to_free_low(min_count); while (min_count < persistent_huge_pages) { - struct page *page = dequeue_huge_page(NULL, 0); + struct page *page = dequeue_huge_page(); if (!page) break; update_and_free_page(page); @@ -1205,12 +1238,13 @@ static int hugetlb_acct_memory(long delta) if (gather_surplus_pages(delta) < 0) goto out; - if (delta > cpuset_mems_nr(free_huge_pages_node)) + if (delta > cpuset_mems_nr(free_huge_pages_node)) { + return_unused_surplus_pages(delta); goto out; + } } ret = 0; - resv_huge_pages += delta; if (delta < 0) return_unused_surplus_pages((unsigned long) -delta); |