zsmalloc: switch from alloc_vm_area to get_vm_area

Just manually pre-fault the PTEs using apply_to_page_range. Co-developed-by: Minchan Kim <[email protected]> Signed-off-by: Christoph Hellwig <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Cc: Boris Ostrovsky <[email protected]> Cc: Chris Wilson <[email protected]> Cc: Jani Nikula <[email protected]> Cc: Joonas Lahtinen <[email protected]> Cc: Juergen Gross <[email protected]> Cc: Matthew Auld <[email protected]> Cc: "Matthew Wilcox (Oracle)" <[email protected]> Cc: Nitin Gupta <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Rodrigo Vivi <[email protected]> Cc: Stefano Stabellini <[email protected]> Cc: Tvrtko Ursulin <[email protected]> Cc: Uladzislau Rezki (Sony) <[email protected]> Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Linus Torvalds <[email protected]>
sm00th · Oct 18, 2020 · d1b6d2e · d1b6d2e
1 parent eeb4a05
commit d1b6d2e
Showing 1 changed file with 8 additions and 2 deletions.
diff --git 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)