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Commit d85f69b0 authored by Mike Kravetz's avatar Mike Kravetz Committed by Linus Torvalds
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mm/hugetlb: alloc_huge_page handle areas hole punched by fallocate 



Areas hole punched by fallocate will not have entries in the
region/reserve map.  However, shared mappings with min_size subpool
reservations may still have reserved pages.  alloc_huge_page needs to
handle this special case and do the proper accounting.

Signed-off-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: default avatarHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 1fb1b0e9

mm/hugetlb.c

+39 −15
Original line number Diff line number Diff line
@@ -1733,34 +1733,58 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, 
	struct hugepage_subpool *spool = subpool_vma(vma);

	struct hstate *h = hstate_vma(vma);

	struct page *page;

	long chg, commit;

	long map_chg, map_commit;

	long gbl_chg;

	int ret, idx;

	struct hugetlb_cgroup *h_cg;



	idx = hstate_index(h);

	/*

	 * Processes that did not create the mapping will have no

	 * reserves and will not have accounted against subpool

	 * limit. Check that the subpool limit can be made before

	 * satisfying the allocation MAP_NORESERVE mappings may also

	 * need pages and subpool limit allocated allocated if no reserve

	 * mapping overlaps.

	 * Examine the region/reserve map to determine if the process

	 * has a reservation for the page to be allocated.  A return

	 * code of zero indicates a reservation exists (no change).

	 */

	chg = vma_needs_reservation(h, vma, addr);

	if (chg < 0)

	map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);

	if (map_chg < 0)

		return ERR_PTR(-ENOMEM);

	if (chg || avoid_reserve)

		if (hugepage_subpool_get_pages(spool, 1) < 0) {



	/*

	 * Processes that did not create the mapping will have no

	 * reserves as indicated by the region/reserve map. Check

	 * that the allocation will not exceed the subpool limit.

	 * Allocations for MAP_NORESERVE mappings also need to be

	 * checked against any subpool limit.

	 */

	if (map_chg || avoid_reserve) {

		gbl_chg = hugepage_subpool_get_pages(spool, 1);

		if (gbl_chg < 0) {

			vma_end_reservation(h, vma, addr);

			return ERR_PTR(-ENOSPC);

		}



		/*

		 * Even though there was no reservation in the region/reserve

		 * map, there could be reservations associated with the

		 * subpool that can be used.  This would be indicated if the

		 * return value of hugepage_subpool_get_pages() is zero.

		 * However, if avoid_reserve is specified we still avoid even

		 * the subpool reservations.

		 */

		if (avoid_reserve)

			gbl_chg = 1;

	}



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

	if (ret)

		goto out_subpool_put;



	spin_lock(&hugetlb_lock);

	page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg);

	/*

	 * glb_chg is passed to indicate whether or not a page must be taken

	 * from the global free pool (global change).  gbl_chg == 0 indicates

	 * a reservation exists for the allocation.

	 */

	page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);

	if (!page) {

		spin_unlock(&hugetlb_lock);

		page = alloc_buddy_huge_page(h, NUMA_NO_NODE);
@@ -1776,8 +1800,8 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, 


	set_page_private(page, (unsigned long)spool);



	commit = vma_commit_reservation(h, vma, addr);

	if (unlikely(chg > commit)) {

	map_commit = vma_commit_reservation(h, vma, addr);

	if (unlikely(map_chg > map_commit)) {

		/*

		 * The page was added to the reservation map between

		 * vma_needs_reservation and vma_commit_reservation.
@@ -1797,7 +1821,7 @@ static 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_subpool_put:

	if (chg || avoid_reserve)

	if (map_chg || avoid_reserve)

		hugepage_subpool_put_pages(spool, 1);

	vma_end_reservation(h, vma, addr);

	return ERR_PTR(-ENOSPC);