diff options
| -rw-r--r-- | include/linux/memory_hotplug.h | 20 | ||||
| -rw-r--r-- | include/linux/mmzone.h | 6 | ||||
| -rw-r--r-- | mm/compaction.c | 14 | ||||
| -rw-r--r-- | mm/memory_hotplug.c | 2 | ||||
| -rw-r--r-- | mm/page_alloc.c | 1 | ||||
| -rw-r--r-- | mm/vmscan.c | 27 |
6 files changed, 55 insertions, 15 deletions
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 54675791bc50..51052969dbfe 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -215,6 +215,22 @@ void put_online_mems(void); void mem_hotplug_begin(void); void mem_hotplug_done(void); +/* See kswapd_is_running() */ +static inline void pgdat_kswapd_lock(pg_data_t *pgdat) +{ + mutex_lock(&pgdat->kswapd_lock); +} + +static inline void pgdat_kswapd_unlock(pg_data_t *pgdat) +{ + mutex_unlock(&pgdat->kswapd_lock); +} + +static inline void pgdat_kswapd_lock_init(pg_data_t *pgdat) +{ + mutex_init(&pgdat->kswapd_lock); +} + #else /* ! CONFIG_MEMORY_HOTPLUG */ #define pfn_to_online_page(pfn) \ ({ \ @@ -251,6 +267,10 @@ static inline bool movable_node_is_enabled(void) { return false; } + +static inline void pgdat_kswapd_lock(pg_data_t *pgdat) {} +static inline void pgdat_kswapd_unlock(pg_data_t *pgdat) {} +static inline void pgdat_kswapd_lock_init(pg_data_t *pgdat) {} #endif /* ! CONFIG_MEMORY_HOTPLUG */ /* diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index fd61347b4b1f..18cf0fc5ce67 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -956,8 +956,10 @@ typedef struct pglist_data { atomic_t nr_writeback_throttled;/* nr of writeback-throttled tasks */ unsigned long nr_reclaim_start; /* nr pages written while throttled * when throttling started. */ - struct task_struct *kswapd; /* Protected by - mem_hotplug_begin/done() */ +#ifdef CONFIG_MEMORY_HOTPLUG + struct mutex kswapd_lock; +#endif + struct task_struct *kswapd; /* Protected by kswapd_lock */ int kswapd_order; enum zone_type kswapd_highest_zoneidx; diff --git a/mm/compaction.c b/mm/compaction.c index 640fa76228dd..262c4676b32c 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1981,9 +1981,21 @@ static inline bool is_via_compact_memory(int order) return order == -1; } +/* + * Determine whether kswapd is (or recently was!) running on this node. + * + * pgdat_kswapd_lock() pins pgdat->kswapd, so a concurrent kswapd_stop() can't + * zero it. + */ static bool kswapd_is_running(pg_data_t *pgdat) { - return pgdat->kswapd && task_is_running(pgdat->kswapd); + bool running; + + pgdat_kswapd_lock(pgdat); + running = pgdat->kswapd && task_is_running(pgdat->kswapd); + pgdat_kswapd_unlock(pgdat); + + return running; } /* diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index dc727aee4ad3..9ae1f98548b1 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1940,8 +1940,8 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages, node_states_clear_node(node, &arg); if (arg.status_change_nid >= 0) { - kswapd_stop(node); kcompactd_stop(node); + kswapd_stop(node); } writeback_set_ratelimit(); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 1d4278115d71..09386b81e68e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7616,6 +7616,7 @@ static void __meminit pgdat_init_internals(struct pglist_data *pgdat) int i; pgdat_resize_init(pgdat); + pgdat_kswapd_lock_init(pgdat); pgdat_init_split_queue(pgdat); pgdat_init_kcompactd(pgdat); diff --git a/mm/vmscan.c b/mm/vmscan.c index bb993b21953d..02e720c83901 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4643,16 +4643,17 @@ void kswapd_run(int nid) { pg_data_t *pgdat = NODE_DATA(nid); - if (pgdat->kswapd) - return; - - pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid); - if (IS_ERR(pgdat->kswapd)) { - /* failure at boot is fatal */ - BUG_ON(system_state < SYSTEM_RUNNING); - pr_err("Failed to start kswapd on node %d\n", nid); - pgdat->kswapd = NULL; + pgdat_kswapd_lock(pgdat); + if (!pgdat->kswapd) { + pgdat->kswapd = kthread_run(kswapd, pgdat, "kswapd%d", nid); + if (IS_ERR(pgdat->kswapd)) { + /* failure at boot is fatal */ + BUG_ON(system_state < SYSTEM_RUNNING); + pr_err("Failed to start kswapd on node %d\n", nid); + pgdat->kswapd = NULL; + } } + pgdat_kswapd_unlock(pgdat); } /* @@ -4661,12 +4662,16 @@ void kswapd_run(int nid) */ void kswapd_stop(int nid) { - struct task_struct *kswapd = NODE_DATA(nid)->kswapd; + pg_data_t *pgdat = NODE_DATA(nid); + struct task_struct *kswapd; + pgdat_kswapd_lock(pgdat); + kswapd = pgdat->kswapd; if (kswapd) { kthread_stop(kswapd); - NODE_DATA(nid)->kswapd = NULL; + pgdat->kswapd = NULL; } + pgdat_kswapd_unlock(pgdat); } static int __init kswapd_init(void) |