By distributing both the allocation and the initialization tasks across
multiple threads, the initialization of 2M hugetlb will be faster,
thereby improving the boot speed.
Here are some test results:
test case no patch(ms) patched(ms) saved
------------------- -------------- ------------- --------
256c2T(4 node) 2M 3336 1051 68.52%
128c1T(2 node) 2M 1943 716 63.15%
Signed-off-by: Gang Li <ligang.bdlg@xxxxxxxxxxxxx>
Tested-by: David Rientjes <rientjes@xxxxxxxxxx>
Reviewed-by: Muchun Song <muchun.song@xxxxxxxxx>
---
mm/hugetlb.c | 73 ++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 56 insertions(+), 17 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d1ce1a52ad504..3ce957b3e350b 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -35,6 +35,7 @@
#include <linux/delayacct.h>
#include <linux/memory.h>
#include <linux/mm_inline.h>
+#include <linux/padata.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
@@ -3510,6 +3511,30 @@ static void __init hugetlb_hstate_alloc_pages_errcheck(unsigned long allocated,
}
}
+static void __init hugetlb_pages_alloc_boot_node(unsigned long start, unsigned long end, void *arg)
+{
+ struct hstate *h = (struct hstate *)arg;
+ int i, num = end - start;
+ nodemask_t node_alloc_noretry;
+ LIST_HEAD(folio_list);
+ int next_node = first_online_node;
+
+ /* Bit mask controlling how hard we retry per-node allocations.*/
+ nodes_clear(node_alloc_noretry);
+
+ for (i = 0; i < num; ++i) {
+ struct folio *folio = alloc_pool_huge_folio(h, &node_states[N_MEMORY],
+ &node_alloc_noretry, &next_node);
+ if (!folio)
+ break;
+
+ list_move(&folio->lru, &folio_list);
+ cond_resched();
+ }
+
+ prep_and_add_allocated_folios(h, &folio_list);
+}
+
static unsigned long __init hugetlb_gigantic_pages_alloc_boot(struct hstate *h)
{
unsigned long i;
@@ -3525,26 +3550,40 @@ static unsigned long __init hugetlb_gigantic_pages_alloc_boot(struct hstate *h)
static unsigned long __init hugetlb_pages_alloc_boot(struct hstate *h)
{
- unsigned long i;
- struct folio *folio;
- LIST_HEAD(folio_list);
- nodemask_t node_alloc_noretry;
-
- /* Bit mask controlling how hard we retry per-node allocations.*/
- nodes_clear(node_alloc_noretry);
+ struct padata_mt_job job = {
+ .fn_arg = h,
+ .align = 1,
+ .numa_aware = true
+ };
- for (i = 0; i < h->max_huge_pages; ++i) {
- folio = alloc_pool_huge_folio(h, &node_states[N_MEMORY],
- &node_alloc_noretry);
- if (!folio)
- break;
- list_add(&folio->lru, &folio_list);
- cond_resched();
- }
+ job.thread_fn = hugetlb_pages_alloc_boot_node;
+ job.start = 0;
+ job.size = h->max_huge_pages;
- prep_and_add_allocated_folios(h, &folio_list);
+ /*
+ * job.max_threads is twice the num_node_state(N_MEMORY),
+ *
+ * Tests below indicate that a multiplier of 2 significantly improves
+ * performance, and although larger values also provide improvements,
+ * the gains are marginal.
+ *
+ * Therefore, choosing 2 as the multiplier strikes a good balance between
+ * enhancing parallel processing capabilities and maintaining efficient
+ * resource management.
+ *
+ * +------------+-------+-------+-------+-------+-------+
+ * | multiplier | 1 | 2 | 3 | 4 | 5 |
+ * +------------+-------+-------+-------+-------+-------+
+ * | 256G 2node | 358ms | 215ms | 157ms | 134ms | 126ms |
+ * | 2T 4node | 979ms | 679ms | 543ms | 489ms | 481ms |
+ * | 50G 2node | 71ms | 44ms | 37ms | 30ms | 31ms |
+ * +------------+-------+-------+-------+-------+-------+
+ */
+ job.max_threads = num_node_state(N_MEMORY) * 2;
+ job.min_chunk = h->max_huge_pages / num_node_state(N_MEMORY) / 2;
+ padata_do_multithreaded(&job);
- return i;
+ return h->nr_huge_pages;
}
/*
--
2.20.1
