[PATCH 16/33] sched/isolation: Flush vmstat workqueues on cpuset isolated partition change
From: Frederic Weisbecker <frederic@kernel.org>
Date: 2026-01-25 22:48:02
Also in:
cgroups, linux-block, linux-mm, linux-pci, lkml, netdev
Subsystem:
memory management, memory management - core, scheduler, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Ingo Molnar, Peter Zijlstra, Juri Lelli, Vincent Guittot, Linus Torvalds
The HK_TYPE_DOMAIN housekeeping cpumask is now modifiable at runtime. In order to synchronize against vmstat workqueue to make sure that no asynchronous vmstat work is still pending or executing on a newly made isolated CPU, the housekeeping susbsystem must flush the vmstat workqueues. This involves flushing the whole mm_percpu_wq workqueue, shared with LRU drain, introducing here a welcome side effect. Signed-off-by: Frederic Weisbecker <frederic@kernel.org> --- include/linux/vmstat.h | 2 ++ kernel/sched/isolation.c | 1 + kernel/sched/sched.h | 1 + mm/vmstat.c | 5 +++++ 4 files changed, 9 insertions(+)
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 3398a345bda8..1909b945b3ea 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h@@ -303,6 +303,7 @@ int calculate_pressure_threshold(struct zone *zone); int calculate_normal_threshold(struct zone *zone); void set_pgdat_percpu_threshold(pg_data_t *pgdat, int (*calculate_pressure)(struct zone *)); +void vmstat_flush_workqueue(void); #else /* CONFIG_SMP */ /*
@@ -403,6 +404,7 @@ static inline void __dec_node_page_state(struct page *page, static inline void refresh_zone_stat_thresholds(void) { } static inline void cpu_vm_stats_fold(int cpu) { } static inline void quiet_vmstat(void) { } +static inline void vmstat_flush_workqueue(void) { } static inline void drain_zonestat(struct zone *zone, struct per_cpu_zonestat *pzstats) { }
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index f4053ebf4027..160b3fcab209 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c@@ -145,6 +145,7 @@ int housekeeping_update(struct cpumask *isol_mask) synchronize_rcu(); mem_cgroup_flush_workqueue(); + vmstat_flush_workqueue(); kfree(old);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 65dfa48e54b7..2d0c408fca0b 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h@@ -68,6 +68,7 @@ #include <linux/types.h> #include <linux/u64_stats_sync_api.h> #include <linux/uaccess.h> +#include <linux/vmstat.h> #include <linux/wait_api.h> #include <linux/wait_bit.h> #include <linux/workqueue_api.h>
diff --git a/mm/vmstat.c b/mm/vmstat.c
index ed19c0d42de6..d6e814c82952 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c@@ -2124,6 +2124,11 @@ static void vmstat_shepherd(struct work_struct *w); static DECLARE_DEFERRABLE_WORK(shepherd, vmstat_shepherd); +void vmstat_flush_workqueue(void) +{ + flush_workqueue(mm_percpu_wq); +} + static void vmstat_shepherd(struct work_struct *w) { int cpu;
--
2.51.1