From: Mina Almasry <almasrymina@xxxxxxxxxx> Subject: hugetlb_cgroup: support noreserve mappings Support MAP_NORESERVE accounting as part of the new counter. For each hugepage allocation, at allocation time we check if there is a reservation for this allocation or not. If there is a reservation for this allocation, then this allocation was charged at reservation time, and we don't re-account it. If there is no reserevation for this allocation, we charge the appropriate hugetlb_cgroup. The hugetlb_cgroup to uncharge for this allocation is stored in page[3].private. We use new APIs added in an earlier patch to set this pointer. Link: http://lkml.kernel.org/r/20200211213128.73302-6-almasrymina@xxxxxxxxxx Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx> Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Greg Thelen <gthelen@xxxxxxxxxx> Cc: Sandipan Das <sandipan@xxxxxxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Shuah Khan <shuah@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/hugetlb.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) --- a/mm/hugetlb.c~hugetlb_cgroup-support-noreserve-mappings +++ a/mm/hugetlb.c @@ -1345,6 +1345,8 @@ static void __free_huge_page(struct page clear_page_huge_active(page); hugetlb_cgroup_uncharge_page(hstate_index(h), pages_per_huge_page(h), page); + hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h), + pages_per_huge_page(h), page); if (restore_reserve) h->resv_huge_pages++; @@ -2281,6 +2283,7 @@ struct page *alloc_huge_page(struct vm_a long gbl_chg; int ret, idx; struct hugetlb_cgroup *h_cg; + bool deferred_reserve; idx = hstate_index(h); /* @@ -2318,9 +2321,19 @@ struct page *alloc_huge_page(struct vm_a gbl_chg = 1; } + /* If this allocation is not consuming a reservation, charge it now. + */ + deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma); + if (deferred_reserve) { + ret = hugetlb_cgroup_charge_cgroup_rsvd( + idx, pages_per_huge_page(h), &h_cg); + if (ret) + goto out_subpool_put; + } + ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); if (ret) - goto out_subpool_put; + goto out_uncharge_cgroup_reservation; spin_lock(&hugetlb_lock); /* @@ -2343,6 +2356,14 @@ struct page *alloc_huge_page(struct vm_a /* Fall through */ } hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); + /* If allocation is not consuming a reservation, also store the + * hugetlb_cgroup pointer on the page. + */ + if (deferred_reserve) { + hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h), + h_cg, page); + } + spin_unlock(&hugetlb_lock); set_page_private(page, (unsigned long)spool); @@ -2367,6 +2388,10 @@ struct page *alloc_huge_page(struct vm_a out_uncharge_cgroup: hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); +out_uncharge_cgroup_reservation: + if (deferred_reserve) + hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h), + h_cg); out_subpool_put: if (map_chg || avoid_reserve) hugepage_subpool_put_pages(spool, 1); _
