Just manually pre-fault the PTEs using apply_to_page_range. Co-developed-by: Minchan Kim <minchan@xxxxxxxxxx> Signed-off-by: Christoph Hellwig <hch@xxxxxx> --- mm/zsmalloc.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index c36fdff9a37131..918c7b019b3d78 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1122,10 +1122,16 @@ static inline int __zs_cpu_up(struct mapping_area *area) */ if (area->vm) return 0; - area->vm = alloc_vm_area(PAGE_SIZE * 2, NULL); + area->vm = get_vm_area(PAGE_SIZE * 2, 0); if (!area->vm) return -ENOMEM; - return 0; + + /* + * Populate ptes in advance to avoid pte allocation with GFP_KERNEL + * in non-preemtible context of zs_map_object. + */ + return apply_to_page_range(&init_mm, (unsigned long)area->vm->addr, + PAGE_SIZE * 2, NULL, NULL); } static inline void __zs_cpu_down(struct mapping_area *area) -- 2.28.0
