[PATCH v8 3/8] hugetlb: perform vmemmap optimization on a list of pages

Mike Kravetz
2023-10-19T02:32:32Z

When adding hugetlb pages to the pool, we first create a list of the
allocated pages before adding to the pool. Pass this list of pages to a
new routine hugetlb_vmemmap_optimize_folios() for vmemmap optimization.

Due to significant differences in vmemmmap initialization for bootmem
allocated hugetlb pages, a new routine prep_and_add_bootmem_folios
is created.

We also modify the routine vmemmap_should_optimize() to check for pages
that are already optimized. There are code paths that might request
vmemmap optimization twice and we want to make sure this is not
attempted.

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
---
mm/hugetlb.c | 43 +++++++++++++++++++++++++++++++++++--------
mm/hugetlb_vmemmap.c | 11 +++++++++++
mm/hugetlb_vmemmap.h | 5 +++++
3 files changed, 51 insertions(+), 8 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 559f7c71c596..8b171f866d0a 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2282,6 +2282,9 @@ static void prep_and_add_allocated_folios(struct hstate *h,
unsigned long flags;
struct folio *folio, *tmp_f;

+ /* 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) {
@@ -3344,6 +3347,35 @@ static void __init hugetlb_folio_init_vmemmap(struct folio *folio,
prep_compound_head((struct page *)folio, huge_page_order(h));
}

+static void __init prep_and_add_bootmem_folios(struct hstate *h,
+ struct list_head *folio_list)
+{
+ unsigned long flags;
+ struct folio *folio, *tmp_f;
+
+ /* 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)) {
+ /*
+ * If HVO fails, initialize all tail struct pages
+ * We do not worry about potential long lock hold
+ * time as this is early in boot and there should
+ * be no contention.
+ */
+ hugetlb_folio_init_tail_vmemmap(folio,
+ HUGETLB_VMEMMAP_RESERVE_PAGES,
+ pages_per_huge_page(h));
+ }
+ __prep_account_new_huge_page(h, folio_nid(folio));
+ enqueue_hugetlb_folio(h, folio);
+ }
+ 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_ORDER) pages.
@@ -3364,7 +3396,7 @@ static void __init gather_bootmem_prealloc(void)
* in this list. If so, process each size separately.
*/
if (h != prev_h && prev_h != NULL)
- prep_and_add_allocated_folios(prev_h, &folio_list);
+ prep_and_add_bootmem_folios(prev_h, &folio_list);
prev_h = h;

VM_BUG_ON(!hstate_is_gigantic(h));
@@ -3372,12 +3404,7 @@ static void __init gather_bootmem_prealloc(void)

hugetlb_folio_init_vmemmap(folio, h,
HUGETLB_VMEMMAP_RESERVE_PAGES);
- __prep_new_hugetlb_folio(h, folio);
- /* If HVO fails, initialize all tail struct pages */
- if (!HPageVmemmapOptimized(&folio->page))
- hugetlb_folio_init_tail_vmemmap(folio,
- HUGETLB_VMEMMAP_RESERVE_PAGES,
- pages_per_huge_page(h));
+ init_new_hugetlb_folio(h, folio);
list_add(&folio->lru, &folio_list);

/*
@@ -3389,7 +3416,7 @@ static void __init gather_bootmem_prealloc(void)
cond_resched();
}

- prep_and_add_allocated_folios(h, &folio_list);
+ prep_and_add_bootmem_folios(h, &folio_list);
}

static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate *h, int nid)
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 76682d1d79a7..4558b814ffab 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -483,6 +483,9 @@ int hugetlb_vmemmap_restore(const struct hstate *h, struct page *head)
/* Return true iff a HugeTLB whose vmemmap should and can be optimized. */
static bool vmemmap_should_optimize(const struct hstate *h, const struct page *head)
{
+ if (HPageVmemmapOptimized((struct page *)head))
+ return false;
+
if (!READ_ONCE(vmemmap_optimize_enabled))
return false;

@@ -572,6 +575,14 @@ void hugetlb_vmemmap_optimize(const struct hstate *h, struct page *head)
SetHPageVmemmapOptimized(head);
}

+void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list)
+{
+ struct folio *folio;
+
+ list_for_each_entry(folio, folio_list, lru)
+ hugetlb_vmemmap_optimize(h, &folio->page);
+}
+
static struct ctl_table hugetlb_vmemmap_sysctls[] = {
{
.procname = "hugetlb_optimize_vmemmap",
diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h
index 4573899855d7..c512e388dbb4 100644
--- a/mm/hugetlb_vmemmap.h
+++ b/mm/hugetlb_vmemmap.h
@@ -20,6 +20,7 @@
#ifdef CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
int hugetlb_vmemmap_restore(const struct hstate *h, struct page *head);
void hugetlb_vmemmap_optimize(const struct hstate *h, struct page *head);
+void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list);

static inline unsigned int hugetlb_vmemmap_size(const struct hstate *h)
{
@@ -48,6 +49,10 @@ static inline void hugetlb_vmemmap_optimize(const struct hstate *h, struct page
{
}

+static inline void hugetlb_vmemmap_optimize_folios(struct hstate *h, struct list_head *folio_list)
+{
+}
+
static inline unsigned int hugetlb_vmemmap_optimizable_size(const struct hstate *h)
{
return 0;
--
2.41.0