Re: [PATCH v2] mm/hugetlb: initialize hugetlb_usage in mm_init

On Thu, Aug 26, 2021 at 03:17:42PM +0800, Liu Zixian wrote:

After fork, the child process will get incorrect (2x) hugetlb_usage. If a process uses 5 2MB hugetlb pages in an anonymous mapping, HugetlbPages: 10240 kB and then forks, the child will show, HugetlbPages: 20480 kB The reason for double the amount is because hugetlb_usage will be copied from the parent and then increased when we copy page tables from parent to child. Child will have 2x actual usage.

Fix this by adding hugetlb_count_init in mm_init.

Fixes: 5d317b2b6536 ("mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status") Signed-off-by: Liu Zixian liuzixian4@huawei.com

Thank you for the fix.

Reviewed-by: Naoya Horiguchi naoya.horiguchi@nec.com