From 597b7305dd8bafdb3aef4957d97128bc90af8e9f Mon Sep 17 00:00:00 2001 From: Michal Hocko Date: Fri, 31 Mar 2017 15:11:47 -0700 Subject: [PATCH] mm: move mm_percpu_wq initialization earlier Yang Li has reported that drain_all_pages triggers a WARN_ON which means that this function is called earlier than the mm_percpu_wq is initialized on arm64 with CMA configured: WARNING: CPU: 2 PID: 1 at mm/page_alloc.c:2423 drain_all_pages+0x244/0x25c Modules linked in: CPU: 2 PID: 1 Comm: swapper/0 Not tainted 4.11.0-rc1-next-20170310-00027-g64dfbc5 #127 Hardware name: Freescale Layerscape 2088A RDB Board (DT) task: ffffffc07c4a6d00 task.stack: ffffffc07c4a8000 PC is at drain_all_pages+0x244/0x25c LR is at start_isolate_page_range+0x14c/0x1f0 [...] drain_all_pages+0x244/0x25c start_isolate_page_range+0x14c/0x1f0 alloc_contig_range+0xec/0x354 cma_alloc+0x100/0x1fc dma_alloc_from_contiguous+0x3c/0x44 atomic_pool_init+0x7c/0x208 arm64_dma_init+0x44/0x4c do_one_initcall+0x38/0x128 kernel_init_freeable+0x1a0/0x240 kernel_init+0x10/0xfc ret_from_fork+0x10/0x20 Fix this by moving the whole setup_vmstat which is an initcall right now to init_mm_internals which will be called right after the WQ subsystem is initialized. Link: http://lkml.kernel.org/r/20170315164021.28532-1-mhocko@kernel.org Signed-off-by: Michal Hocko Reported-by: Yang Li Tested-by: Yang Li Tested-by: Xiaolong Ye Cc: Mel Gorman Cc: Vlastimil Babka Cc: Tetsuo Handa Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 2 ++ init/main.c | 2 ++ mm/vmstat.c | 4 +--- 3 files changed, 5 insertions(+), 3 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 5f01c88f0800da..00a8fa7e366a03 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -32,6 +32,8 @@ struct user_struct; struct writeback_control; struct bdi_writeback; +void init_mm_internals(void); + #ifndef CONFIG_NEED_MULTIPLE_NODES /* Don't use mapnrs, do it properly */ extern unsigned long max_mapnr; diff --git a/init/main.c b/init/main.c index f9c9d994820327..b0c11cbf5ddf8a 100644 --- a/init/main.c +++ b/init/main.c @@ -1022,6 +1022,8 @@ static noinline void __init kernel_init_freeable(void) workqueue_init(); + init_mm_internals(); + do_pre_smp_initcalls(); lockup_detector_init(); diff --git a/mm/vmstat.c b/mm/vmstat.c index b1947f0cbee2f9..89f95396ec46be 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1764,7 +1764,7 @@ static int vmstat_cpu_dead(unsigned int cpu) #endif -static int __init setup_vmstat(void) +void __init init_mm_internals(void) { #ifdef CONFIG_SMP int ret; @@ -1792,9 +1792,7 @@ static int __init setup_vmstat(void) proc_create("vmstat", S_IRUGO, NULL, &proc_vmstat_file_operations); proc_create("zoneinfo", S_IRUGO, NULL, &proc_zoneinfo_file_operations); #endif - return 0; } -module_init(setup_vmstat) #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_COMPACTION)