Re: [PATCH v4 7/7] hugetlb: parallelize 1G hugetlb initialization
From: Gang Li
Date: Wed Jan 24 2024 - 05:52:38 EST
On 2024/1/24 17:23, Muchun Song wrote:
On 2024/1/18 20:39, Gang Li wrote:
Optimizing the initialization speed of 1G huge pages through
parallelization.
1G hugetlbs are allocated from bootmem, a process that is already
very fast and does not currently require optimization. Therefore,
we focus on parallelizing only the initialization phase in
`gather_bootmem_prealloc`.
Here are some test results:
test no patch(ms) patched(ms) saved
------------------- -------------- ------------- --------
256c2t(4 node) 1G 4745 2024 57.34%
What does "256c2t" mean?
A machine with 256 core and 2T memory.
128c1t(2 node) 1G 3358 1712 49.02%
12t 1G 77000 18300 76.23%
Signed-off-by: Gang Li <gang.li@xxxxxxxxx>
Tested-by: David Rientjes <rientjes@xxxxxxxxxx>
---
include/linux/hugetlb.h | 2 +-
mm/hugetlb.c | 42 +++++++++++++++++++++++++++++++++--------
2 files changed, 35 insertions(+), 9 deletions(-)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index c1ee640d87b1..77b30a8c6076 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -178,7 +178,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, struct
vm_area_struct *vma,
struct address_space *hugetlb_page_mapping_lock_write(struct page
*hpage);
extern int sysctl_hugetlb_shm_group;
-extern struct list_head huge_boot_pages;
+extern struct list_head huge_boot_pages[MAX_NUMNODES];
/* arch callbacks */
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 9b348ba418f5..2f4b77630ada 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -69,7 +69,7 @@ static bool hugetlb_cma_folio(struct folio *folio,
unsigned int order)
#endif
static unsigned long hugetlb_cma_size __initdata;
-__initdata LIST_HEAD(huge_boot_pages);
+__initdata struct list_head huge_boot_pages[MAX_NUMNODES];
/* for command line parsing */
static struct hstate * __initdata parsed_hstate;
@@ -3301,7 +3301,7 @@ int alloc_bootmem_huge_page(struct hstate *h,
int nid)
int __alloc_bootmem_huge_page(struct hstate *h, int nid)
{
struct huge_bootmem_page *m = NULL; /* initialize for clang */
- int nr_nodes, node;
+ int nr_nodes, node = nid;
Why not use nid directly in the following list_add()?
`node` may be changed in `for_each_node_mask_to_alloc`.
/* do node specific alloc */
if (nid != NUMA_NO_NODE) {
@@ -3339,7 +3339,7 @@ int __alloc_bootmem_huge_page(struct hstate *h,
int nid)
huge_page_size(h) - PAGE_SIZE);
/* Put them into a private list first because mem_map is not up
yet */
INIT_LIST_HEAD(&m->list);
- list_add(&m->list, &huge_boot_pages);
+ list_add(&m->list, &huge_boot_pages[node]);
m->hstate = h;
return 1;
}
@@ -3390,8 +3390,6 @@ static void __init
prep_and_add_bootmem_folios(struct hstate *h,
/* Send list for bulk vmemmap optimization processing */
hugetlb_vmemmap_optimize_folios(h, folio_list);
- /* Add all new pool pages to free lists in one lock cycle */
- spin_lock_irqsave(&hugetlb_lock, flags);
list_for_each_entry_safe(folio, tmp_f, folio_list, lru) {
if (!folio_test_hugetlb_vmemmap_optimized(folio)) {
/*
@@ -3404,23 +3402,27 @@ static void __init
prep_and_add_bootmem_folios(struct hstate *h,
HUGETLB_VMEMMAP_RESERVE_PAGES,
pages_per_huge_page(h));
}
+ /* Subdivide locks to achieve better parallel performance *
+ spin_lock_irqsave(&hugetlb_lock, flags);
__prep_account_new_huge_page(h, folio_nid(folio));
enqueue_hugetlb_folio(h, folio);
+ spin_unlock_irqrestore(&hugetlb_lock, flags);
}
- spin_unlock_irqrestore(&hugetlb_lock, flags);
}
/*
* Put bootmem huge pages into the standard lists after mem_map is up.
* Note: This only applies to gigantic (order > MAX_PAGE_ORDER) pages.
*/
-static void __init gather_bootmem_prealloc(void)
+static void __init __gather_bootmem_prealloc(unsigned long start,
unsigned long end, void *arg)
This function name could be gather_bootmem_prealloc_node.
LGTM.
+
{
+ int nid = start;
LIST_HEAD(folio_list);
struct huge_bootmem_page *m;
struct hstate *h = NULL, *prev_h = NULL;
- list_for_each_entry(m, &huge_boot_pages, list) {
+ list_for_each_entry(m, &huge_boot_pages[nid], list) {
struct page *page = virt_to_page(m);
struct folio *folio = (void *)page;
@@ -3453,6 +3455,22 @@ static void __init gather_bootmem_prealloc(void)
prep_and_add_bootmem_folios(h, &folio_list);
}
+static void __init gather_bootmem_prealloc(void)
+{
+ struct padata_mt_job job = {
+ .thread_fn = __gather_bootmem_prealloc,
+ .fn_arg = NULL,
+ .start = 0,
+ .size = num_node_state(N_MEMORY),
+ .align = 1,
+ .min_chunk = 1,
+ .max_threads = num_node_state(N_MEMORY),
+ .numa_aware = true,
+ };
+
+ padata_do_multithreaded(&job);
+}
+
static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate
*h, int nid)
{
unsigned long i;
@@ -3602,6 +3620,14 @@ static void __init
hugetlb_hstate_alloc_pages(struct hstate *h)
return;
}
+ /* hugetlb_hstate_alloc_pages will be called many times, init
huge_boot_pages once*/
s/init/initialize/g
And you miss a black right before "*/".
OK
+ if (huge_boot_pages[0].next == NULL) {
It it not intuitive. I'd like to use a 'initialied' variable
Would it make the code look a bit redundant?
to indicate whether it has been initialized. BTW, it can be
marked as __initdata.
OK