Allow huge page allocations to use GFP_HIGH_MOVABLE
Huge pages are not movable so are not allocated from ZONE_MOVABLE. However,
as ZONE_MOVABLE will always have pages that can be migrated or reclaimed, it
can be used to satisfy hugepage allocations even when the system has been
running a long time. This allows an administrator to resize the hugepage pool
at runtime depending on the size of ZONE_MOVABLE.
This patch adds a new sysctl called hugepages_treat_as_movable. When a
non-zero value is written to it, future allocations for the huge page pool
will use ZONE_MOVABLE. Despite huge pages being non-movable, we do not
introduce additional external fragmentation of note as huge pages are always
the largest contiguous block we care about.
[akpm@linux-foundation.org: various fixes]
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index acc0fb3..5898067 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -27,6 +27,9 @@
static struct list_head hugepage_freelists[MAX_NUMNODES];
static unsigned int nr_huge_pages_node[MAX_NUMNODES];
static unsigned int free_huge_pages_node[MAX_NUMNODES];
+static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
+unsigned long hugepages_treat_as_movable;
+
/*
* Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages
*/
@@ -68,12 +71,13 @@
{
int nid;
struct page *page = NULL;
- struct zonelist *zonelist = huge_zonelist(vma, address);
+ struct zonelist *zonelist = huge_zonelist(vma, address,
+ htlb_alloc_mask);
struct zone **z;
for (z = zonelist->zones; *z; z++) {
nid = zone_to_nid(*z);
- if (cpuset_zone_allowed_softwall(*z, GFP_HIGHUSER) &&
+ if (cpuset_zone_allowed_softwall(*z, htlb_alloc_mask) &&
!list_empty(&hugepage_freelists[nid]))
break;
}
@@ -113,7 +117,7 @@
prev_nid = nid;
spin_unlock(&nid_lock);
- page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN,
+ page = alloc_pages_node(nid, htlb_alloc_mask|__GFP_COMP|__GFP_NOWARN,
HUGETLB_PAGE_ORDER);
if (page) {
set_compound_page_dtor(page, free_huge_page);
@@ -263,6 +267,19 @@
max_huge_pages = set_max_huge_pages(max_huge_pages);
return 0;
}
+
+int hugetlb_treat_movable_handler(struct ctl_table *table, int write,
+ struct file *file, void __user *buffer,
+ size_t *length, loff_t *ppos)
+{
+ proc_dointvec(table, write, file, buffer, length, ppos);
+ if (hugepages_treat_as_movable)
+ htlb_alloc_mask = GFP_HIGHUSER_MOVABLE;
+ else
+ htlb_alloc_mask = GFP_HIGHUSER;
+ return 0;
+}
+
#endif /* CONFIG_SYSCTL */
int hugetlb_report_meminfo(char *buf)