Commit 08cf9faf authored by Mina Almasry's avatar Mina Almasry Committed by Linus Torvalds
Browse files

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.

Signed-off-by: default avatarMina Almasry <almasrymina@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Sandipan Das <sandipan@linux.ibm.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Link: http://lkml.kernel.org/r/20200211213128.73302-6-almasrymina@google.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 075a61d0

mm/hugetlb.c

+26 −1
Original line number Diff line number Diff line
@@ -1345,6 +1345,8 @@ static 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);

	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_area_struct *vma, 
	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_area_struct *vma, 
			gbl_chg = 1;

	}



	ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);

	/* 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_uncharge_cgroup_reservation;



	spin_lock(&hugetlb_lock);

	/*
@@ -2343,6 +2356,14 @@ struct page *alloc_huge_page(struct vm_area_struct *vma, 
		/* 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_area_struct *vma, 


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);

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