> On Sep 20, 2023, at 04:49, Mike Kravetz <mike.kravetz@xxxxxxxxxx> wrote: > > On 09/19/23 11:10, Muchun Song wrote: >> >> >> On 2023/9/19 07:01, Mike Kravetz wrote: >>> 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@xxxxxxxxxx> >>> --- >>> mm/hugetlb.c | 50 +++++++++++++++++++++++++++++++++++++------- >>> mm/hugetlb_vmemmap.c | 11 ++++++++++ >>> mm/hugetlb_vmemmap.h | 5 +++++ >>> 3 files changed, 58 insertions(+), 8 deletions(-) >>> >>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >>> index 8624286be273..d6f3db3c1313 100644 >>> --- a/mm/hugetlb.c >>> +++ b/mm/hugetlb.c >>> @@ -2269,6 +2269,11 @@ static void prep_and_add_allocated_folios(struct hstate *h, >>> { >>> struct folio *folio, *tmp_f; >>> + /* >>> + * Send list for bulk vmemmap optimization processing >>> + */ >> >> From the kernel development document, one-line comment format is "/**/". >> > > Will change the comments introduced here. BTW, there are some places as well, please updates all, thanks. > >>> + hugetlb_vmemmap_optimize_folios(h, folio_list); >>> + >>> /* >>> * Add all new pool pages to free lists in one lock cycle >>> */ >>> @@ -3309,6 +3314,40 @@ 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) >>> +{ >>> + 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_irq(&hugetlb_lock); >>> + 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_irq(&hugetlb_lock); >>> + >>> + INIT_LIST_HEAD(folio_list); >> >> I'm not sure what is the purpose of the reinitialization to list head? >> > > There really is no purpose. This was copied from > prep_and_add_allocated_folios which also has this unnecessary call. It is > unnecessary as enqueue_hugetlb_folio() will do a list_move for each > folio on the list. Therefore, at the end of the loop we KNOW the list > is empty. Right. > > I will remove here and in prep_and_add_allocated_folios. Thanks. > > Thanks, > -- > Mike Kravetz