* [PATCH v3 03/20] mm, hugetlb: fix subpool accounting handling [not found] <520c10e8.1kKQVx1mpwqXywyM%akpm@linux-foundation.org> @ 2013-09-06 5:19 ` Joonsoo Kim 2013-09-06 5:19 ` Joonsoo Kim 0 siblings, 1 reply; 2+ messages in thread From: Joonsoo Kim @ 2013-09-06 5:19 UTC (permalink / raw) To: Andrew Morton Cc: Rik van Riel, Mel Gorman, Michal Hocko, Aneesh Kumar K.V, KAMEZAWA Hiroyuki, Hugh Dickins, Davidlohr Bueso, David Gibson, linux-mm, linux-kernel, Joonsoo Kim, Wanpeng Li, Naoya Horiguchi, Hillf Danton, Joonsoo Kim There is a case that we attempt to allocate a hugepage with chg = 0 and avoid_reserve = 1. Although chg = 0 means that it has a reserved hugepage, we wouldn't use it, since avoid_reserve = 1 represents that we don't want to allocate a hugepage from a reserved pool. This happens when the parent process that created a MAP_PRIVATE mapping is about to perform a COW due to a shared page count and it attempt to satisfy the allocation without using the existing reserves. In this case, we would not dequeue a reserved hugepage and, instead, try to allocate a new hugepage. Therefore, we should check subpool counter for a new hugepage. This patch implement it. Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> --- Replenishing commit message and adding reviewed-by tag. diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 12b6581..ea1ae0a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1144,13 +1144,14 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, chg = vma_needs_reservation(h, vma, addr); if (chg < 0) return ERR_PTR(-ENOMEM); - if (chg) - if (hugepage_subpool_get_pages(spool, chg)) + if (chg || avoid_reserve) + if (hugepage_subpool_get_pages(spool, 1)) return ERR_PTR(-ENOSPC); ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); if (ret) { - hugepage_subpool_put_pages(spool, chg); + if (chg || avoid_reserve) + hugepage_subpool_put_pages(spool, 1); return ERR_PTR(-ENOSPC); } spin_lock(&hugetlb_lock); @@ -1162,7 +1163,8 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); - hugepage_subpool_put_pages(spool, chg); + if (chg || avoid_reserve) + hugepage_subpool_put_pages(spool, 1); return ERR_PTR(-ENOSPC); } spin_lock(&hugetlb_lock); -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH v3 03/20] mm, hugetlb: fix subpool accounting handling 2013-09-06 5:19 ` [PATCH v3 03/20] mm, hugetlb: fix subpool accounting handling Joonsoo Kim @ 2013-09-06 5:19 ` Joonsoo Kim 0 siblings, 0 replies; 2+ messages in thread From: Joonsoo Kim @ 2013-09-06 5:19 UTC (permalink / raw) To: Andrew Morton Cc: Rik van Riel, Mel Gorman, Michal Hocko, Aneesh Kumar K.V, KAMEZAWA Hiroyuki, Hugh Dickins, Davidlohr Bueso, David Gibson, linux-mm, linux-kernel, Joonsoo Kim, Wanpeng Li, Naoya Horiguchi, Hillf Danton, Joonsoo Kim There is a case that we attempt to allocate a hugepage with chg = 0 and avoid_reserve = 1. Although chg = 0 means that it has a reserved hugepage, we wouldn't use it, since avoid_reserve = 1 represents that we don't want to allocate a hugepage from a reserved pool. This happens when the parent process that created a MAP_PRIVATE mapping is about to perform a COW due to a shared page count and it attempt to satisfy the allocation without using the existing reserves. In this case, we would not dequeue a reserved hugepage and, instead, try to allocate a new hugepage. Therefore, we should check subpool counter for a new hugepage. This patch implement it. Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> --- Replenishing commit message and adding reviewed-by tag. diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 12b6581..ea1ae0a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1144,13 +1144,14 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, chg = vma_needs_reservation(h, vma, addr); if (chg < 0) return ERR_PTR(-ENOMEM); - if (chg) - if (hugepage_subpool_get_pages(spool, chg)) + if (chg || avoid_reserve) + if (hugepage_subpool_get_pages(spool, 1)) return ERR_PTR(-ENOSPC); ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); if (ret) { - hugepage_subpool_put_pages(spool, chg); + if (chg || avoid_reserve) + hugepage_subpool_put_pages(spool, 1); return ERR_PTR(-ENOSPC); } spin_lock(&hugetlb_lock); @@ -1162,7 +1163,8 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); - hugepage_subpool_put_pages(spool, chg); + if (chg || avoid_reserve) + hugepage_subpool_put_pages(spool, 1); return ERR_PTR(-ENOSPC); } spin_lock(&hugetlb_lock); -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a> ^ permalink raw reply [flat|nested] 2+ messages in thread
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2013-09-06 5:19 ` [PATCH v3 03/20] mm, hugetlb: fix subpool accounting handling Joonsoo Kim
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