Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933650AbbGUSLT (ORCPT ); Tue, 21 Jul 2015 14:11:19 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:47786 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933612AbbGUSLM (ORCPT ); Tue, 21 Jul 2015 14:11:12 -0400 From: Mike Kravetz To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org Cc: Dave Hansen , Naoya Horiguchi , David Rientjes , Hugh Dickins , Davidlohr Bueso , Aneesh Kumar , Hillf Danton , Christoph Hellwig , Andrew Morton , Michal Hocko , Mike Kravetz Subject: [PATCH v4 07/10] mm/hugetlb: alloc_huge_page handle areas hole punched by fallocate Date: Tue, 21 Jul 2015 11:09:41 -0700 Message-Id: <1437502184-14269-8-git-send-email-mike.kravetz@oracle.com> X-Mailer: git-send-email 2.1.0 In-Reply-To: <1437502184-14269-1-git-send-email-mike.kravetz@oracle.com> References: <1437502184-14269-1-git-send-email-mike.kravetz@oracle.com> X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4159 Lines: 113 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: Mike Kravetz --- mm/hugetlb.c | 54 +++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 39 insertions(+), 15 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index f9d3faf..efcd58c 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1735,34 +1735,58 @@ 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); @@ -1778,8 +1802,8 @@ 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. @@ -1799,7 +1823,7 @@ 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); -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/