On 2/22/19 6:01 AM, Jing Xiangfeng wrote: Thanks, just a couple small changes. > User can change a node specific hugetlb count. i.e. > /sys/devices/system/node/node1/hugepages/hugepages-2048kB Please make that, /sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages > the calculated value of count is a total number of huge pages. It could > be overflow when a user entering a crazy high value. If so, the total > number of huge pages could be a small value which is not user expect. > We can simply fix it by setting count to ULONG_MAX, then it goes on. This > may be more in line with user's intention of allocating as many huge pages > as possible. > > Signed-off-by: Jing Xiangfeng <jingxiangfeng@xxxxxxxxxx> > --- > mm/hugetlb.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index afef616..18fa7d7 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -2423,7 +2423,10 @@ static ssize_t __nr_hugepages_store_common(bool obey_mempolicy, > * per node hstate attribute: adjust count to global, > * but restrict alloc/free to the specified node. > */ > + unsigned long old_count = count; > count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; Also, adding a comment here about checking for overflow would help people reading the code. Something like, /* * If user specified count causes overflow, set to * largest possible value. */ -- Mike Kravetz > + if (count < old_count) > + count = ULONG_MAX; > init_nodemask_of_node(nodes_allowed, nid); > } else > nodes_allowed = &node_states[N_MEMORY]; >
