On 2016/8/9 1:14, Mike Kravetz wrote: > On 08/07/2016 07:49 PM, zhongjiang wrote: >> From: zhong jiang <zhongji...@huawei.com> >> >> when memory hotplug enable, free hugepages will be freed if movable node >> offline. >> therefore, /proc/sys/vm/nr_hugepages will be incorrect. >> >> The patch fix it by reduce the max_huge_pages when the node offline. >> >> Signed-off-by: zhong jiang <zhongji...@huawei.com> >> --- >> mm/hugetlb.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/mm/hugetlb.c b/mm/hugetlb.c >> index f904246..3356e3a 100644 >> --- a/mm/hugetlb.c >> +++ b/mm/hugetlb.c >> @@ -1448,6 +1448,7 @@ static void dissolve_free_huge_page(struct page *page) >> list_del(&page->lru); >> h->free_huge_pages--; >> h->free_huge_pages_node[nid]--; >> + h->max_huge_pages--; >> update_and_free_page(h, page); >> } >> spin_unlock(&hugetlb_lock); >> > Adding Naoya as he was the original author of this code. > > >From quick look it appears that the huge page will be migrated (allocated > on another node). If my understanding is correct, then max_huge_pages > should not be adjusted here. > we need to take free hugetlb pages into account. of course, the allocated huge pages is no need to reduce. The patch just reduce the free hugetlb pages count.
Thanks zhongjiang
