From: Thomas Prescher <thomas.prescher@xxxxxxxxxxxxxxxxxxxxx>
Add a command line option that enables control of how many
threads should be used to allocate huge pages.
Signed-off-by: Thomas Prescher <thomas.prescher@xxxxxxxxxxxxxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 9 +++++++
Documentation/admin-guide/mm/hugetlbpage.rst | 10 ++++++++
mm/hugetlb.c | 31 +++++++++++++++++++++----
3 files changed, 46 insertions(+), 4 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index fb8752b42ec8582b8750d7e014c4d76166fa2fc1..1937ee02c1f883ecd910bab33cdb9194bddbd9b1 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1882,6 +1882,15 @@
Documentation/admin-guide/mm/hugetlbpage.rst.
Format: size[KMG]
+ hugepage_alloc_threads=
+ [HW] The number of threads that should be used to
+ allocate hugepages during boot. This option can be
+ used to improve system bootup time when allocating
+ a large amount of huge pages.
+ The default value is 25% of the available hardware threads.
+
+ Note that this parameter only applies to non-gigantic huge pages.
+
hugetlb_cma= [HW,CMA,EARLY] The size of a CMA area used for allocation
of gigantic hugepages. Or using node format, the size
of a CMA area per node can be specified.
diff --git a/Documentation/admin-guide/mm/hugetlbpage.rst b/Documentation/admin-guide/mm/hugetlbpage.rst
index f34a0d798d5b533f30add99a34f66ba4e1c496a3..67a941903fd2231e6c082cffb4c9179ee094b208 100644
--- a/Documentation/admin-guide/mm/hugetlbpage.rst
+++ b/Documentation/admin-guide/mm/hugetlbpage.rst
@@ -145,7 +145,17 @@ hugepages
It will allocate 1 2M hugepage on node0 and 2 2M hugepages on node1.
If the node number is invalid, the parameter will be ignored.
+hugepage_alloc_threads
+ Specify the number of threads that should be used to allocate hugepages
+ during boot. This parameter can be used to improve system bootup time
+ when allocating a large amount of huge pages.
+ The default value is 25% of the available hardware threads.
+ Example to use 8 allocation threads::
+
+ hugepage_alloc_threads=8
+
+ Note that this parameter only applies to non-gigantic huge pages.
default_hugepagesz
Specify the default huge page size. This parameter can
only be specified once on the command line. default_hugepagesz can
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e9b1b3e2b9d467f067d54359e1401a03f9926108..98dbfa18bee01d01b40cc7c650cd3eca5eae2457 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -70,6 +70,7 @@ static unsigned long __initdata default_hstate_max_huge_pages;
static bool __initdata parsed_valid_hugepagesz = true;
static bool __initdata parsed_default_hugepagesz;
static unsigned int default_hugepages_in_node[MAX_NUMNODES] __initdata;
+static unsigned long hugepage_allocation_threads __initdata;
/*
* Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
@@ -3429,8 +3430,6 @@ static unsigned long __init hugetlb_pages_alloc_boot(struct hstate *h)
.numa_aware = true
};
- unsigned int num_allocation_threads = max(num_online_cpus() / 4, 1);
-
job.thread_fn = hugetlb_pages_alloc_boot_node;
job.start = 0;
job.size = h->max_huge_pages;
@@ -3451,9 +3450,13 @@ static unsigned long __init hugetlb_pages_alloc_boot(struct hstate *h)
* | cascade lake 192 cpus | 39s | 20s | 11s | 10s | 9s |
* +-----------------------+-------+-------+-------+-------+-------+
*/
+ if (hugepage_allocation_threads == 0) {
+ hugepage_allocation_threads = num_online_cpus() / 4;
+ hugepage_allocation_threads = max(hugepage_allocation_threads, 1);
+ }
- job.max_threads = num_allocation_threads;
- job.min_chunk = h->max_huge_pages / num_allocation_threads;
+ job.max_threads = hugepage_allocation_threads;
+ job.min_chunk = h->max_huge_pages / hugepage_allocation_threads;
padata_do_multithreaded(&job);
return h->nr_huge_pages;
@@ -4766,6 +4769,26 @@ static int __init default_hugepagesz_setup(char *s)
}
__setup("default_hugepagesz=", default_hugepagesz_setup);
+/* hugepage_alloc_threads command line parsing
+ * When set, use this specific number of threads for the boot
+ * allocation of hugepages.
+ */
+static int __init hugepage_alloc_threads_setup(char *s)
+{
+ unsigned long allocation_threads;
+
+ if (kstrtoul(s, 0, &allocation_threads) != 0)
+ return 1;
+
+ if (allocation_threads == 0)
+ return 1;
+
+ hugepage_allocation_threads = allocation_threads;
+
+ return 1;
+}
+__setup("hugepage_alloc_threads=", hugepage_alloc_threads_setup);
+
static unsigned int allowed_mems_nr(struct hstate *h)
{
int node;
--
2.48.1
