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.
> > + 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.
I will remove here and in prep_and_add_allocated_folios.
Thanks,
--
Mike Kravetz
