On 4/13/21 3:47 AM, Oscar Salvador wrote:
> Currently, prep_new_huge_page() performs two functions.
> It sets the right state for a new hugetlb, and increases the hstate's
> counters to account for the new page.
>
> Let us split its functionality into two separate functions, decoupling
> the handling of the counters from initializing a hugepage.
> The outcome is having __prep_new_huge_page(), which only
> initializes the page , and __prep_account_new_huge_page(), which adds
> the new page to the hstate's counters.
>
> This allows us to be able to set a hugetlb without having to worry
> about the counter/locking. It will prove useful in the next patch.
> prep_new_huge_page() still calls both functions.
>
> Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
> ---
> mm/hugetlb.c | 19 ++++++++++++++++---
> 1 file changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index e40d5fe5c63c..0607b2b71ac6 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1483,7 +1483,16 @@ void free_huge_page(struct page *page)
> }
> }
>
> -static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
> +/*
> + * Must be called with the hugetlb lock held
> + */
> +static void __prep_account_new_huge_page(struct hstate *h, int nid)
> +{
> + h->nr_huge_pages++;
> + h->nr_huge_pages_node[nid]++;
I would prefer if we also move setting the destructor to this routine.
set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
That way, PageHuge() will be false until it 'really' is a huge page.
If not, we could potentially go into that retry loop in
dissolve_free_huge_page or alloc_and_dissolve_huge_page in patch 5.
--
Mike Kravetz
> +}
> +
> +static void __prep_new_huge_page(struct page *page)
> {
> INIT_LIST_HEAD(&page->lru);
> set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
> @@ -1491,9 +1500,13 @@ static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
> set_hugetlb_cgroup(page, NULL);
> set_hugetlb_cgroup_rsvd(page, NULL);
> ClearHPageFreed(page);
> +}
> +
> +static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
> +{
> + __prep_new_huge_page(page);
> spin_lock_irq(&hugetlb_lock);
> - h->nr_huge_pages++;
> - h->nr_huge_pages_node[nid]++;
> + __prep_account_new_huge_page(h, nid);
> spin_unlock_irq(&hugetlb_lock);
> }
>
>
