[PATCH v2 6/6] mm: hugetlb: support gigantic surplus pages
From: Huang Shijie <hidden>
Date: 2016-11-14 07:09:14
Also in:
linux-mm
Subsystem:
hugetlb subsystem, memory management, the rest · Maintainers:
Muchun Song, Oscar Salvador, Andrew Morton, Linus Torvalds
When testing the gigantic page whose order is too large for the buddy
allocator, the libhugetlbfs test case "counter.sh" will fail.
The failure is caused by:
1) kernel fails to allocate a gigantic page for the surplus case.
And the gather_surplus_pages() will return NULL in the end.
2) The condition checks for "over-commit" is wrong.
This patch uses __hugetlb_alloc_gigantic_page() to allocate the
gigantic page in the __alloc_huge_page(). After this patch,
gather_surplus_pages() can return a gigantic page for the surplus case.
This patch also changes the condition checks for:
return_unused_surplus_pages()
nr_overcommit_hugepages_store()
hugetlb_overcommit_handler()
After this patch, the counter.sh can pass for the gigantic page.
Signed-off-by: Huang Shijie <redacted>
---
mm/hugetlb.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 58a59f0..08e66ca 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c@@ -1647,7 +1647,7 @@ static struct page *__alloc_huge_page(struct hstate *h, struct page *page; unsigned int r_nid; - if (hstate_is_gigantic(h)) + if (hstate_is_gigantic(h) && !gigantic_page_supported()) return NULL; /*
@@ -1692,7 +1692,10 @@ static struct page *__alloc_huge_page(struct hstate *h, } spin_unlock(&hugetlb_lock); - page = __hugetlb_alloc_buddy_huge_page(h, vma, addr, nid); + if (hstate_is_gigantic(h)) + page = __hugetlb_alloc_gigantic_page(h, vma, addr, nid); + else + page = __hugetlb_alloc_buddy_huge_page(h, vma, addr, nid); spin_lock(&hugetlb_lock); if (page) {
@@ -1859,8 +1862,7 @@ static void return_unused_surplus_pages(struct hstate *h, /* Uncommit the reservation */ h->resv_huge_pages -= unused_resv_pages; - /* Cannot return gigantic pages currently */ - if (hstate_is_gigantic(h)) + if (hstate_is_gigantic(h) && !gigantic_page_supported()) return; nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
@@ -2577,7 +2579,7 @@ static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, unsigned long input; struct hstate *h = kobj_to_hstate(kobj, NULL); - if (hstate_is_gigantic(h)) + if (hstate_is_gigantic(h) && !gigantic_page_supported()) return -EINVAL; err = kstrtoul(buf, 10, &input);
@@ -3018,7 +3020,7 @@ int hugetlb_overcommit_handler(struct ctl_table *table, int write, tmp = h->nr_overcommit_huge_pages; - if (write && hstate_is_gigantic(h)) + if (write && hstate_is_gigantic(h) && !gigantic_page_supported()) return -EINVAL; table->data = &tmp;
--
2.5.5