diff options
| -rw-r--r-- | mm/hugetlb.c | 155 |
1 files changed, 132 insertions, 23 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 8768e5250323..31bbca6b2c90 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -87,6 +87,8 @@ static struct page *dequeue_huge_page(struct vm_area_struct *vma, list_del(&page->lru); free_huge_pages--; free_huge_pages_node[nid]--; + if (vma && vma->vm_flags & VM_MAYSHARE) + resv_huge_pages--; break; } } @@ -214,15 +216,116 @@ static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma, return page; } +/* + * Increase the hugetlb pool such that it can accomodate a reservation + * of size 'delta'. + */ +static int gather_surplus_pages(int delta) +{ + struct list_head surplus_list; + struct page *page, *tmp; + int ret, i; + int needed, allocated; + + needed = (resv_huge_pages + delta) - free_huge_pages; + if (needed <= 0) + return 0; + + allocated = 0; + INIT_LIST_HEAD(&surplus_list); + + ret = -ENOMEM; +retry: + spin_unlock(&hugetlb_lock); + for (i = 0; i < needed; i++) { + page = alloc_buddy_huge_page(NULL, 0); + if (!page) { + /* + * We were not able to allocate enough pages to + * satisfy the entire reservation so we free what + * we've allocated so far. + */ + spin_lock(&hugetlb_lock); + needed = 0; + goto free; + } + + list_add(&page->lru, &surplus_list); + } + allocated += needed; + + /* + * After retaking hugetlb_lock, we need to recalculate 'needed' + * because either resv_huge_pages or free_huge_pages may have changed. + */ + spin_lock(&hugetlb_lock); + needed = (resv_huge_pages + delta) - (free_huge_pages + allocated); + if (needed > 0) + goto 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. + */ + needed += allocated; + ret = 0; +free: + list_for_each_entry_safe(page, tmp, &surplus_list, lru) { + list_del(&page->lru); + if ((--needed) >= 0) + enqueue_huge_page(page); + else + update_and_free_page(page); + } + + return ret; +} + +/* + * When releasing a hugetlb pool reservation, any surplus pages that were + * allocated to satisfy the reservation must be explicitly freed if they were + * never used. + */ +void return_unused_surplus_pages(unsigned long unused_resv_pages) +{ + static int nid = -1; + struct page *page; + unsigned long nr_pages; + + nr_pages = min(unused_resv_pages, surplus_huge_pages); + + while (nr_pages) { + nid = next_node(nid, node_online_map); + if (nid == MAX_NUMNODES) + nid = first_node(node_online_map); + + if (!surplus_huge_pages_node[nid]) + continue; + + if (!list_empty(&hugepage_freelists[nid])) { + page = list_entry(hugepage_freelists[nid].next, + struct page, lru); + list_del(&page->lru); + update_and_free_page(page); + free_huge_pages--; + free_huge_pages_node[nid]--; + surplus_huge_pages--; + surplus_huge_pages_node[nid]--; + nr_pages--; + } + } +} + static struct page *alloc_huge_page(struct vm_area_struct *vma, unsigned long addr) { struct page *page = NULL; + int use_reserved_page = vma->vm_flags & VM_MAYSHARE; spin_lock(&hugetlb_lock); - if (vma->vm_flags & VM_MAYSHARE) - resv_huge_pages--; - else if (free_huge_pages <= resv_huge_pages) + if (!use_reserved_page && (free_huge_pages <= resv_huge_pages)) goto fail; page = dequeue_huge_page(vma, addr); @@ -234,8 +337,6 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, return page; fail: - if (vma->vm_flags & VM_MAYSHARE) - resv_huge_pages++; spin_unlock(&hugetlb_lock); /* @@ -243,7 +344,7 @@ fail: * may have failed due to an undersized hugetlb pool. Try to grab a * surplus huge page from the buddy allocator. */ - if (!(vma->vm_flags & VM_MAYSHARE)) + if (!use_reserved_page) page = alloc_buddy_huge_page(vma, addr); return page; @@ -952,21 +1053,6 @@ static int hugetlb_acct_memory(long delta) int ret = -ENOMEM; spin_lock(&hugetlb_lock); - if ((delta + resv_huge_pages) <= free_huge_pages) { - resv_huge_pages += delta; - ret = 0; - } - spin_unlock(&hugetlb_lock); - return ret; -} - -int hugetlb_reserve_pages(struct inode *inode, long from, long to) -{ - long ret, chg; - - chg = region_chg(&inode->i_mapping->private_list, from, to); - if (chg < 0) - return chg; /* * When cpuset is configured, it breaks the strict hugetlb page * reservation as the accounting is done on a global variable. Such @@ -984,8 +1070,31 @@ int hugetlb_reserve_pages(struct inode *inode, long from, long to) * a best attempt and hopefully to minimize the impact of changing * semantics that cpuset has. */ - if (chg > cpuset_mems_nr(free_huge_pages_node)) - return -ENOMEM; + if (delta > 0) { + if (gather_surplus_pages(delta) < 0) + goto out; + + if (delta > cpuset_mems_nr(free_huge_pages_node)) + goto out; + } + + ret = 0; + resv_huge_pages += delta; + if (delta < 0) + return_unused_surplus_pages((unsigned long) -delta); + +out: + spin_unlock(&hugetlb_lock); + return ret; +} + +int hugetlb_reserve_pages(struct inode *inode, long from, long to) +{ + long ret, chg; + + chg = region_chg(&inode->i_mapping->private_list, from, to); + if (chg < 0) + return chg; ret = hugetlb_acct_memory(chg); if (ret < 0) |
