Vmemmap page allocation is currently tied to restoring a virtual range
and assumes an empty destination list. These constraints prevent it from
being reused when pages are requested independently of a vmemmap range or
appended to an existing list.
Generalize the allocator and give it an all-or-nothing list contract so
the restore and optimization paths can share the same allocation policy.
This also allows HVO head-page allocation to fail gracefully under memory
pressure without triggering the OOM killer.
Signed-off-by: Muchun Song <redacted>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Qi Zheng <qi.zheng@linux.dev>
---
v2:
- Collect Reviewed-by from Lance Yang and Qi Zheng
---
mm/hugetlb_vmemmap.c | 39 ++++++++++++++++++---------------------
1 file changed, 18 insertions(+), 21 deletions(-)
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c
index 0e5b2b182d1b..4b20a8efc067 100644
--- a/mm/hugetlb_vmemmap.c
+++ b/mm/hugetlb_vmemmap.c
@@ -334,28 +334,26 @@ static int vmemmap_remap_free(unsigned long start, unsigned long end,
return ret;
}
-static int alloc_vmemmap_page_list(unsigned long start, unsigned long end,
- struct list_head *list)
+static int alloc_vmemmap_page_list(struct list_head *head, unsigned int nr_pages,
+ int nid)
{
- gfp_t gfp_mask = GFP_KERNEL | __GFP_RETRY_MAYFAIL;
- unsigned long nr_pages = (end - start) >> PAGE_SHIFT;
- int nid = page_to_nid((struct page *)start);
- struct page *page, *next;
- int i;
+ LIST_HEAD(local);
- for (i = 0; i < nr_pages; i++) {
- page = alloc_pages_node(nid, gfp_mask, 0);
- if (!page)
- goto out;
- list_add(&page->lru, list);
+ for (unsigned int i = 0; i < nr_pages; i++) {
+ struct page *page;
+
+ page = alloc_pages_node(nid, GFP_KERNEL | __GFP_RETRY_MAYFAIL, 0);
+ if (!page) {
+ memmap_pages_add(i);
+ free_vmemmap_page_list(&local);
+ return -ENOMEM;
+ }
+ list_add(&page->lru, &local);
}
+ list_splice(&local, head);
memmap_pages_add(nr_pages);
return 0;
-out:
- list_for_each_entry_safe(page, next, list, lru)
- __free_page(page);
- return -ENOMEM;
}
/**@@ -374,13 +372,14 @@ static int vmemmap_remap_alloc(unsigned long start, unsigned long end,
unsigned long flags)
{
LIST_HEAD(vmemmap_pages);
+ int nid = page_to_nid((struct page *)start);
struct vmemmap_remap_walk walk = {
.remap_pte = vmemmap_restore_pte,
.vmemmap_pages = &vmemmap_pages,
.flags = flags,
};
- if (alloc_vmemmap_page_list(start, end, &vmemmap_pages))
+ if (alloc_vmemmap_page_list(&vmemmap_pages, (end - start) / PAGE_SIZE, nid))
return -ENOMEM;
return vmemmap_remap_range(start, end, &walk);@@ -527,15 +526,13 @@ static int __hugetlb_vmemmap_optimize_folio(const struct hstate *h,
*/
folio_set_hugetlb_vmemmap_optimized(folio);
- vmemmap_head = alloc_pages_node(nid, GFP_KERNEL, 0);
- if (!vmemmap_head) {
+ if (alloc_vmemmap_page_list(vmemmap_pages, VMEMMAP_OPTIMIZATION_PAGES, nid)) {
ret = -ENOMEM;
goto out;
}
+ vmemmap_head = list_first_entry(vmemmap_pages, struct page, lru);
copy_page(page_to_virt(vmemmap_head), folio);
- list_add(&vmemmap_head->lru, vmemmap_pages);
- memmap_pages_add(1);
vmemmap_start = (unsigned long)&folio->page;
vmemmap_end = vmemmap_start + hugetlb_vmemmap_size(h);--
2.54.0