Re: [PATCH v9 6/8] hugetlb_cgroup: support noreserve mappings

On Tue, 17 Dec 2019, Mina Almasry wrote:

diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 39eb2fa53a420..3e94f5c2d7cd4 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1367,6 +1367,9 @@ void free_huge_page(struct page *page) clear_page_huge_active(page); hugetlb_cgroup_uncharge_page(hstate_index(h), pages_per_huge_page(h), page, false);

• hugetlb_cgroup_uncharge_page(hstate_index(h), pages_per_huge_page(h),

• 		     page, true);
  

• if (restore_reserve) h->resv_huge_pages++;

@@ -2189,10 +2192,19 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, gbl_chg = 1; }

• /* If this allocation is not consuming a reservation, charge it now.

• */
  

• if (map_chg || avoid_reserve || !vma_resv_map(vma)) {

These conditions are checked three times in this function, maybe better set a bool on the stack and use it throughout the function to guarantee it remains consistent?

bool deferred_reserve = !vma_resv_map(vma) || map_chg || avoid_reserve;

• ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h),
  

• 				   &h_cg, true);
  

• if (ret)
  

• 	goto out_subpool_put;
  

• }
• ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg, false); if (ret)

• goto out_subpool_put;
  

• goto out_uncharge_cgroup_reservation;
  
  

  spin_lock(&hugetlb_lock); /*

@@ -2216,6 +2228,14 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, } hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page, false);

• /* If allocation is not consuming a reservation, also store the

• * hugetlb_cgroup pointer on the page.
  

• */
  

• if (!vma_resv_map(vma) || map_chg || avoid_reserve) {

• hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg,
  

• 			     page, true);
  

• }

• spin_unlock(&hugetlb_lock);

  set_page_private(page, (unsigned long)spool);

@@ -2241,6 +2261,10 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, out_uncharge_cgroup: hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg, false); +out_uncharge_cgroup_reservation:

• if (map_chg || avoid_reserve || !vma_resv_map(vma))

• hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h),
  

• 			       h_cg, true);
  

out_subpool_put: if (map_chg || avoid_reserve) hugepage_subpool_put_pages(spool, 1); -- 2.24.1.735.g03f4e72817-goog