[PATCH] mm/hugetlb: Concentrated releases memory when cmdline specifies node requests for large pages

[suhua]

When HVO is enabled and huge page memory allocs are made, the freed memory
can be aggregated into higher order memory in the following paths, which
facilitates further allocs for higher order memory.

echo 200000 > /proc/sys/vm/nr_hugepages
echo 200000 > /sys/devices/system/node/node*/hugepages/hugepages-2048kB/nr_hugepages
grub： default_hugepagesz=2M hugepagesz=2M hugepages=200000

Currently not support for releasing aggregations to higher order in the
following way, which will releasing to lower order.

grub: default_hugepagesz=2M hugepagesz=2M hugepages=0:100000,1:100000

This patch supports the release of huge page optimizations aggregates to
higher order memory.

eg:
cat /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-xxx ... default_hugepagesz=2M hugepagesz=2M hugepages=0:100000,1:100000

Before:
Free pages count per migrate type at order       0      1      2      3      4      5      6      7      8      9     10
...
Node    0, zone   Normal, type    Unmovable  55282  97039  99307      0      1      1      0      1      1      1      0
Node    0, zone   Normal, type      Movable     25     11    345     87     48     21      2     20      9      3  75061
Node    0, zone   Normal, type  Reclaimable      4      2      2      4      3      0      2      1      1      1      0
Node    0, zone   Normal, type   HighAtomic      0      0      0      0      0      0      0      0      0      0      0
...
Free pages count per migrate type at order       0      1      2      3      4      5      6      7      8      9     10
Node    1, zone   Normal, type    Unmovable  98888  99650  99679      2      3      1      2      2      2      0      0
Node    1, zone   Normal, type      Movable      1      1      0      1      1      0      1      0      1      1  75937
Node    1, zone   Normal, type  Reclaimable      0      0      0      0      0      0      0      0      0      0      0
Node    1, zone   Normal, type   HighAtomic      0      0      0      0      0      0      0      0      0      0      0

After:
Free pages count per migrate type at order       0      1      2      3      4      5      6      7      8      9     10
...
Node    0, zone   Normal, type    Unmovable    152    158     37      2      2      0      3      4      2      6    717
Node    0, zone   Normal, type      Movable      1     37     53      3     55     49     16      6      2      1  75000
Node    0, zone   Normal, type  Reclaimable      1      4      3      1      2      1      1      1      1      1      0
Node    0, zone   Normal, type   HighAtomic      0      0      0      0      0      0      0      0      0      0      0
...
Free pages count per migrate type at order       0      1      2      3      4      5      6      7      8      9     10
Node    1, zone   Normal, type    Unmovable      5      3      2      1      3      4      2      2      2      0    779
Node    1, zone   Normal, type      Movable      1      0      1      1      1      0      1      0      1      1  75849
Node    1, zone   Normal, type  Reclaimable      0      0      0      0      0      0      0      0      0      0      0
Node    1, zone   Normal, type   HighAtomic      0      0      0      0      0      0      0      0      0      0      0

Signed-off-by: suhua <suhua1@xxxxxxxxxxxx>
---
 mm/hugetlb.c | 37 +++++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 190fa05635f4..3441d380c90b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2077,6 +2077,24 @@ static struct folio *only_alloc_fresh_hugetlb_folio(struct hstate *h,
 	return folio;
 }
 
+static struct folio *only_alloc_and_account_fresh_hugetlb_folio(
+		struct hstate *h, gfp_t gfp_mask,
+		int nid, nodemask_t *nmask)
+{
+	struct folio *folio;
+
+	folio = only_alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL);
+	if (!folio)
+		return NULL;
+
+	spin_lock_irq(&hugetlb_lock);
+	h->nr_huge_pages++;
+	h->nr_huge_pages_node[nid]++;
+	spin_unlock_irq(&hugetlb_lock);
+
+	return folio;
+}
+
 /*
  * Common helper to allocate a fresh hugetlb page. All specific allocators
  * should use this function to get new hugetlb pages
@@ -3301,23 +3319,34 @@ static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate *h, int nid)
 {
 	unsigned long i;
 	char buf[32];
+	LIST_HEAD(folio_list);
+	struct folio *folio, *tmp_f;
 
 	for (i = 0; i < h->max_huge_pages_node[nid]; ++i) {
 		if (hstate_is_gigantic(h)) {
 			if (!alloc_bootmem_huge_page(h, nid))
 				break;
 		} else {
-			struct folio *folio;
 			gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
 
-			folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid,
-					&node_states[N_MEMORY]);
+			folio = only_alloc_and_account_fresh_hugetlb_folio(h,
+					gfp_mask, nid, &node_states[N_MEMORY]);
 			if (!folio)
 				break;
-			free_huge_folio(folio); /* free it into the hugepage allocator */
+			list_add(&folio->lru, &folio_list);
 		}
 		cond_resched();
 	}
+
+	if (!list_empty(&folio_list)) {
+		/* Send list for bulk vmemmap optimization processing */
+		hugetlb_vmemmap_optimize_folios(h, &folio_list);
+
+		list_for_each_entry_safe(folio, tmp_f, &folio_list, lru) {
+			free_huge_folio(folio); /* free it into the hugepage allocator */
+		}
+	}
+
 	if (i == h->max_huge_pages_node[nid])
 		return;
 
-- 
2.34.1