From: Usama Arif usama.arif@bytedance.com
mainline inclusion from mainline-v6.7-rc1 commit a9e34ea1f62c1e359ed197ec01d056c25edb2b61 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8JXRC CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
-------------------------------------------
Patch series "mm: hugetlb: Skip initialization of gigantic tail struct pages if freed by HVO", v5.
This series moves the boot time initialization of tail struct pages of a gigantic page to later on in the boot. Only the HUGETLB_VMEMMAP_RESERVE_SIZE / sizeof(struct page) - 1 tail struct pages are initialized at the start. If HVO is successful, then no more tail struct pages need to be initialized. For a 1G hugepage, this series avoid initialization of 262144 - 63 = 262081 struct pages per hugepage.
When tested on a 512G system (allocating 500 1G hugepages), the kexec-boot times with DEFERRED_STRUCT_PAGE_INIT enabled are:
- with patches, HVO enabled: 1.32 seconds - with patches, HVO disabled: 2.15 seconds - without patches, HVO enabled: 3.90 seconds - without patches, HVO disabled: 3.58 seconds
This represents an approximately 70% reduction in boot time and will significantly reduce server downtime when using a large number of gigantic pages.
This patch (of 4):
If tail page prep and initialization is skipped, then the "start" page will not contain the correct nid. Use the nid from first vmemap page.
Link: https://lkml.kernel.org/r/20230913105401.519709-1-usama.arif@bytedance.com Link: https://lkml.kernel.org/r/20230913105401.519709-2-usama.arif@bytedance.com Signed-off-by: Usama Arif usama.arif@bytedance.com Reviewed-by: Muchun Song songmuchun@bytedance.com Reviewed-by: Mike Kravetz mike.kravetz@oracle.com Cc: Fam Zheng fam.zheng@bytedance.com Cc: Mike Rapoport (IBM) rppt@kernel.org Cc: Punit Agrawal punit.agrawal@bytedance.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Jinjiang Tu tujinjiang@huawei.com --- mm/hugetlb_vmemmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index 4b9734777f69..56989b228acd 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -318,7 +318,7 @@ static int vmemmap_remap_free(unsigned long start, unsigned long end, .reuse_addr = reuse, .vmemmap_pages = &vmemmap_pages, }; - int nid = page_to_nid((struct page *)start); + int nid = page_to_nid((struct page *)reuse); gfp_t gfp_mask = GFP_KERNEL | __GFP_THISNODE | __GFP_NORETRY | __GFP_NOWARN;