If the pages for a subpool are reserved, then the reservations
have already been accounted for in the global pool(at mount time).
Therefore, when requesting a new reservation (such as for a
mapping) do not adjust the global reserve count. Also, when
simply unreserving pages for the subpool do not adjust the global
count. However, when actually allocating or freeing a hugepage
be sure to adjust the global reserve count so that it corresponds
with the global free count.
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
---
mm/hugetlb.c | 36 ++++++++++++++++++++++++++++--------
1 file changed, 28 insertions(+), 8 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index c6adf65..394bd8f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -879,7 +879,11 @@ void free_huge_page(struct page *page)
spin_lock(&hugetlb_lock);
hugetlb_cgroup_uncharge_page(hstate_index(h),
pages_per_huge_page(h), page);
- if (restore_reserve)
+ /*
+ * When a hugepage in a reserved subpool is free'ed, the global
+ * reserve count must be adjusted along with the global free count.
+ */
+ if (restore_reserve || hugepage_subpool_reserved(spool))
h->resv_huge_pages++;
if (h->surplus_huge_pages_node[nid]) {
@@ -2466,7 +2470,12 @@ static void hugetlb_vm_op_close(struct vm_area_struct *vma)
kref_put(&resv->refs, resv_map_release);
if (reserve) {
- hugetlb_acct_memory(h, -reserve);
+ /*
+ * For reserved subpools, global reservation counts are
+ * only adjusted at hugepage alloc and free time.
+ */
+ if (!hugepage_subpool_reserved(spool))
+ hugetlb_acct_memory(h, -reserve);
hugepage_subpool_put_pages(spool, reserve);
}
}
@@ -3442,12 +3451,18 @@ int hugetlb_reserve_pages(struct inode *inode,
/*
* Check enough hugepages are available for the reservation.
- * Hand the pages back to the subpool if there are not
+ * Hand the pages back to the subpool if there are not. If
+ * the entire subpool was reserved, we know there are enough
+ * hugepages and the global count already reflects the reservation.
*/
- ret = hugetlb_acct_memory(h, chg);
- if (ret < 0) {
- hugepage_subpool_put_pages(spool, chg);
- goto out_err;
+ if (hugepage_subpool_reserved(spool))
+ ret = 0;
+ else {
+ ret = hugetlb_acct_memory(h, chg);
+ if (ret < 0) {
+ hugepage_subpool_put_pages(spool, chg);
+ goto out_err;
+ }
}
/*
@@ -3483,7 +3498,12 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed)
inode->i_blocks -= (blocks_per_huge_page(h) * freed);
spin_unlock(&inode->i_lock);
- hugepage_subpool_put_pages(spool, (chg - freed));
+ /*
+ * For reserved subpools, global reservation counts are only
+ * adjusted at hugepage alloc and free time.
+ */
+ if (!hugepage_subpool_reserved(spool))
+ hugepage_subpool_put_pages(spool, (chg - freed));
hugetlb_acct_memory(h, -(chg - freed));
}
--
2.1.0
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