This patch split alloc_fresh_huge_page_node into 2 parts:
- fast path without __GFP_REPEAT flag
- slow path with __GFP_REPEAT flag
Thus, if there is a server with uneven numa memory layout:
available: 7 nodes (0-6)
node 0 cpus: 0 1 2 3 4 5 6 7
node 0 size: 6603 MB
node 0 free: 91 MB
node 1 cpus:
node 1 size: 12527 MB
node 1 free: 157 MB
node 2 cpus:
node 2 size: 15087 MB
node 2 free: 189 MB
node 3 cpus:
node 3 size: 16111 MB
node 3 free: 205 MB
node 4 cpus: 8 9 10 11 12 13 14 15
node 4 size: 24815 MB
node 4 free: 310 MB
node 5 cpus:
node 5 size: 4095 MB
node 5 free: 61 MB
node 6 cpus:
node 6 size: 22750 MB
node 6 free: 283 MB
node distances:
node 0 1 2 3 4 5 6
0: 10 20 40 40 40 40 40
1: 20 10 40 40 40 40 40
2: 40 40 10 20 40 40 40
3: 40 40 20 10 40 40 40
4: 40 40 40 40 10 20 40
5: 40 40 40 40 20 10 40
6: 40 40 40 40 40 40 10
In this case node 5 has less memory and we will alloc the hugepages
from these nodes one by one.
After this patch, we will not trigger too early direct memory/kswap
reclaim for node 5 if there are enough memory in other nodes.
Signed-off-by: Jia He <hejianet@xxxxxxxxx>
---
mm/hugetlb.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index c7025c1..f2415ce 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1364,10 +1364,19 @@ static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid)
{
struct page *page;
+ /* fast path without __GFP_REPEAT */
page = __alloc_pages_node(nid,
htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
__GFP_REPEAT|__GFP_NOWARN,
huge_page_order(h));
+
+ /* slow path with __GFP_REPEAT*/
+ if (!page)
+ page = __alloc_pages_node(nid,
+ htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE|
+ __GFP_NOWARN,
+ huge_page_order(h));
+
if (page) {
prep_new_huge_page(h, page, nid);
}
--
2.5.5
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