From: Tang Yizhou tangyizhou@huawei.com

ascend inclusion category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I46DPJ CVE: NA

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We found a hungtask problem when do direct compact in __alloc_pages_nodemask:

vmalloc_hugepage_user -> __vmalloc_node_range -> __vmalloc_area_node -> sp_alloc_pages -> alloc_huge_page_node -> alloc_fresh_huge_page -> __alloc_pages_nodemask.

Set PF_MEMALLOC then direct reclaim and direct compact won't be called.

Signed-off-by: Tang Yizhou tangyizhou@huawei.com Reviewed-by: Ding Tianhong dingtianhong@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/share_pool.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/mm/share_pool.c b/mm/share_pool.c index 3e4e05f20c5ce..e5a71e25964c1 100644 --- a/mm/share_pool.c +++ b/mm/share_pool.c @@ -3219,9 +3219,15 @@ void sp_group_post_exit(struct mm_struct *mm) struct page *sp_alloc_pages(struct vm_struct *area, gfp_t mask, unsigned int page_order, int node) { - if (area->flags & VM_HUGE_PAGES) - return hugetlb_alloc_hugepage(NUMA_NO_NODE, HUGETLB_ALLOC_NONE); - else + struct page *page; + unsigned int noreclaim_flag = 0; + + if (area->flags & VM_HUGE_PAGES) { + noreclaim_flag = memalloc_noreclaim_save(); + page = hugetlb_alloc_hugepage(NUMA_NO_NODE, HUGETLB_ALLOC_NONE); + memalloc_noreclaim_restore(noreclaim_flag); + return page; + } else return alloc_pages_node(node, mask, page_order); }