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authorMike Kravetz <mike.kravetz@oracle.com>2016-05-19 17:11:01 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-05-19 19:12:14 -0700
commit09a95e29cb30a3930db22d340ddd072a82b6b0db (patch)
tree0b959a138dc8dd62452faa461a4c1a769bd771bc
parent0edaf86cf1a6a97d811fc34765ddbcbc310de564 (diff)
mm/hugetlb: optimize minimum size (min_size) accounting
It was observed that minimum size accounting associated with the hugetlbfs min_size mount option may not perform optimally and as expected. As huge pages/reservations are released from the filesystem and given back to the global pools, they are reserved for subsequent filesystem use as long as the subpool reserved count is less than subpool minimum size. It does not take into account used pages within the filesystem. The filesystem size limits are not exceeded and this is technically not a bug. However, better behavior would be to wait for the number of used pages/reservations associated with the filesystem to drop below the minimum size before taking reservations to satisfy minimum size. An optimization is also made to the hugepage_subpool_get_pages() routine which is called when pages/reservations are allocated. This does not change behavior, but simply avoids the accounting if all reservations have already been taken (subpool reserved count == 0). Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: David Rientjes <rientjes@google.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/hugetlb.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 5856093f9062..fb37ef810655 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -144,7 +144,8 @@ static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
}
}
- if (spool->min_hpages != -1) { /* minimum size accounting */
+ /* minimum size accounting */
+ if (spool->min_hpages != -1 && spool->rsv_hpages) {
if (delta > spool->rsv_hpages) {
/*
* Asking for more reserves than those already taken on
@@ -182,7 +183,8 @@ static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
if (spool->max_hpages != -1) /* maximum size accounting */
spool->used_hpages -= delta;
- if (spool->min_hpages != -1) { /* minimum size accounting */
+ /* minimum size accounting */
+ if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
if (spool->rsv_hpages + delta <= spool->min_hpages)
ret = 0;
else