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 <jingxiangf...@huawei.com>
> ---
> 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];
>
