From ed0a826ce3025832c8d8b79924fd638f75b62bb7 Mon Sep 17 00:00:00 2001 From: Marco Crivellari Date: Tue, 13 Jan 2026 12:46:30 +0100 Subject: [PATCH] mm: add WQ_PERCPU to alloc_workqueue users This continues the effort to refactor workqueue APIs, which began with the introduction of new workqueues and a new alloc_workqueue flag in: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") The refactoring is going to alter the default behavior of alloc_workqueue() to be unbound by default. With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn't explicitly specify WQ_UNBOUND must now use WQ_PERCPU. For more details see the Link tag below. In order to keep alloc_workqueue() behavior identical, explicitly request WQ_PERCPU. [akpm@linux-foundation.org: fix mm/slub.c] [akpm@linux-foundation.org: fix kmem_cache_init_late() properly, per Sebastian] Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/ Link: https://lkml.kernel.org/r/20260113114630.152942-4-marco.crivellari@suse.com Signed-off-by: Marco Crivellari Suggested-by: Tejun Heo Reviewed-by: Sebastian Andrzej Siewior Reviewed-by: Frederic Weisbecker Cc: Alexander Potapenko Cc: David Hildenbrand Cc: Dmitry Vyukov Cc: Johannes Weiner Cc: Lai jiangshan Cc: "Liam R. Howlett" Cc: Lorenzo Stoakes Cc: Marco Elver Cc: Michal Hocko Cc: Mike Rapoport Cc: Muchun Song Cc: Roman Gushchin Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/backing-dev.c | 2 +- mm/slub.c | 3 ++- mm/vmstat.c | 3 ++- 3 files changed, 5 insertions(+), 3 deletions(-) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 69361742893ad..e319bd5e8b75c 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -974,7 +974,7 @@ static int __init cgwb_init(void) * system_percpu_wq. Put them in a separate wq and limit concurrency. * There's no point in executing many of these in parallel. */ - cgwb_release_wq = alloc_workqueue("cgwb_release", 0, 1); + cgwb_release_wq = alloc_workqueue("cgwb_release", WQ_PERCPU, 1); if (!cgwb_release_wq) return -ENOMEM; diff --git a/mm/slub.c b/mm/slub.c index 861592ac54257..409d16695c8bc 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -8542,7 +8542,8 @@ void __init kmem_cache_init(void) void __init kmem_cache_init_late(void) { - flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM, 0); + flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM | WQ_PERCPU, + 0); WARN_ON(!flushwq); } diff --git a/mm/vmstat.c b/mm/vmstat.c index 23e176e1d09d7..99270713e0c13 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -2259,7 +2259,8 @@ void __init init_mm_internals(void) { int ret __maybe_unused; - mm_percpu_wq = alloc_workqueue("mm_percpu_wq", WQ_MEM_RECLAIM, 0); + mm_percpu_wq = alloc_workqueue("mm_percpu_wq", + WQ_MEM_RECLAIM | WQ_PERCPU, 0); #ifdef CONFIG_SMP ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead", -- 2.47.3