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-rw-r--r--mm/hugetlb.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 89e6286a7f5..20e04c64468 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -296,8 +296,10 @@ 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 +337,12 @@ 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) {
@@ -371,6 +376,9 @@ 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) {
@@ -1205,12 +1213,13 @@ 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);