| Message ID | 20220720025920.1373558-7-aneesh.kumar@linux.ibm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/demotion: Memory tiers and demotion | expand |
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> writes: > Also update different helpes to use NODE_DATA()->memtier. Since > node specific memtier can change based on the reassignment of > NUMA node to a different memory tiers, accessing NODE_DATA()->memtier > needs to happen under an rcu read lock or memory_tier_lock. > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> > --- > include/linux/mmzone.h | 3 ++ > mm/memory-tiers.c | 65 +++++++++++++++++++++++++++++++++++------- > 2 files changed, 57 insertions(+), 11 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index aab70355d64f..353812495a70 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -928,6 +928,9 @@ typedef struct pglist_data { > /* Per-node vmstats */ > struct per_cpu_nodestat __percpu *per_cpu_nodestats; > atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS]; > +#ifdef CONFIG_NUMA > + struct memory_tier __rcu *memtier; > +#endif > } pg_data_t; > > #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) > diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c > index a8cfe2ca3903..4715f9b96a44 100644 > --- a/mm/memory-tiers.c > +++ b/mm/memory-tiers.c > @@ -138,13 +138,18 @@ static struct memory_tier *find_create_memory_tier(unsigned int perf_level) > > static struct memory_tier *__node_get_memory_tier(int node) > { > - struct memory_tier *memtier; > + pg_data_t *pgdat; > > - list_for_each_entry(memtier, &memory_tiers, list) { > - if (node_isset(node, memtier->nodelist)) > - return memtier; > - } > - return NULL; > + pgdat = NODE_DATA(node); > + if (!pgdat) > + return NULL; > + /* > + * Since we hold memory_tier_lock, we can avoid > + * RCU read locks when accessing the details. No > + * parallel updates are possible here. > + */ > + return rcu_dereference_check(pgdat->memtier, > + lockdep_is_held(&memory_tier_lock)); > } > > #ifdef CONFIG_MIGRATION > @@ -277,6 +282,29 @@ static inline void disable_all_migrate_targets(void) {} > static inline void establish_migration_targets(void) {} > #endif /* CONFIG_MIGRATION */ > > +static void memtier_node_set(int node, struct memory_tier *memtier) > +{ > + pg_data_t *pgdat; > + struct memory_tier *current_memtier; > + > + pgdat = NODE_DATA(node); > + if (!pgdat) > + return; > + /* > + * Make sure we mark the memtier NULL before we assign the new memory tier > + * to the NUMA node. This make sure that anybody looking at NODE_DATA > + * finds a NULL memtier or the one which is still valid. > + */ > + current_memtier = rcu_dereference_check(pgdat->memtier, > + lockdep_is_held(&memory_tier_lock)); > + rcu_assign_pointer(pgdat->memtier, NULL); > + synchronize_rcu(); > + if (current_memtier) > + node_clear(node, current_memtier->nodelist); If pgdat->memtier == NULL, we don't need to set it to NULL and call synchronize_rcu(). That is, + current_memtier = rcu_dereference_check(pgdat->memtier, + lockdep_is_held(&memory_tier_lock)); + if (current_memtier) { + rcu_assign_pointer(pgdat->memtier, NULL); + synchronize_rcu(); + node_clear(node, current_memtier->nodelist); + } Same for clear_node_memory_tier(). Best Regards, Huang, Ying > + node_set(node, memtier->nodelist); > + rcu_assign_pointer(pgdat->memtier, memtier); > +} > + > static void init_node_memory_tier(int node) > { > int perf_level; > @@ -295,7 +323,7 @@ static void init_node_memory_tier(int node) > if (!memtier) { > perf_level = node_devices[node]->perf_level; > memtier = find_create_memory_tier(perf_level); > - node_set(node, memtier->nodelist); > + memtier_node_set(node, memtier); > } > establish_migration_targets(); > mutex_unlock(&memory_tier_lock); > @@ -303,12 +331,25 @@ static void init_node_memory_tier(int node) > > static void clear_node_memory_tier(int node) > { > - struct memory_tier *memtier; > + pg_data_t *pgdat; > + struct memory_tier *current_memtier; > + > + pgdat = NODE_DATA(node); > + if (!pgdat) > + return; > > mutex_lock(&memory_tier_lock); > - memtier = __node_get_memory_tier(node); > - if (memtier) { > - node_clear(node, memtier->nodelist); > + /* > + * Make sure we mark the memtier NULL before we assign the new memory tier > + * to the NUMA node. This make sure that anybody looking at NODE_DATA > + * finds a NULL memtier or the one which is still valid. > + */ > + current_memtier = rcu_dereference_check(pgdat->memtier, > + lockdep_is_held(&memory_tier_lock)); > + rcu_assign_pointer(pgdat->memtier, NULL); > + synchronize_rcu(); > + if (current_memtier) { > + node_clear(node, current_memtier->nodelist); > establish_migration_targets(); > } > mutex_unlock(&memory_tier_lock); > @@ -383,6 +424,8 @@ static int __init memory_tier_init(void) > > if (!node_property->perf_level) > node_property->perf_level = default_memtier_perf_level; > + > + rcu_assign_pointer(NODE_DATA(node)->memtier, memtier); > } > mutex_unlock(&memory_tier_lock);
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index aab70355d64f..353812495a70 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -928,6 +928,9 @@ typedef struct pglist_data { /* Per-node vmstats */ struct per_cpu_nodestat __percpu *per_cpu_nodestats; atomic_long_t vm_stat[NR_VM_NODE_STAT_ITEMS]; +#ifdef CONFIG_NUMA + struct memory_tier __rcu *memtier; +#endif } pg_data_t; #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index a8cfe2ca3903..4715f9b96a44 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -138,13 +138,18 @@ static struct memory_tier *find_create_memory_tier(unsigned int perf_level) static struct memory_tier *__node_get_memory_tier(int node) { - struct memory_tier *memtier; + pg_data_t *pgdat; - list_for_each_entry(memtier, &memory_tiers, list) { - if (node_isset(node, memtier->nodelist)) - return memtier; - } - return NULL; + pgdat = NODE_DATA(node); + if (!pgdat) + return NULL; + /* + * Since we hold memory_tier_lock, we can avoid + * RCU read locks when accessing the details. No + * parallel updates are possible here. + */ + return rcu_dereference_check(pgdat->memtier, + lockdep_is_held(&memory_tier_lock)); } #ifdef CONFIG_MIGRATION @@ -277,6 +282,29 @@ static inline void disable_all_migrate_targets(void) {} static inline void establish_migration_targets(void) {} #endif /* CONFIG_MIGRATION */ +static void memtier_node_set(int node, struct memory_tier *memtier) +{ + pg_data_t *pgdat; + struct memory_tier *current_memtier; + + pgdat = NODE_DATA(node); + if (!pgdat) + return; + /* + * Make sure we mark the memtier NULL before we assign the new memory tier + * to the NUMA node. This make sure that anybody looking at NODE_DATA + * finds a NULL memtier or the one which is still valid. + */ + current_memtier = rcu_dereference_check(pgdat->memtier, + lockdep_is_held(&memory_tier_lock)); + rcu_assign_pointer(pgdat->memtier, NULL); + synchronize_rcu(); + if (current_memtier) + node_clear(node, current_memtier->nodelist); + node_set(node, memtier->nodelist); + rcu_assign_pointer(pgdat->memtier, memtier); +} + static void init_node_memory_tier(int node) { int perf_level; @@ -295,7 +323,7 @@ static void init_node_memory_tier(int node) if (!memtier) { perf_level = node_devices[node]->perf_level; memtier = find_create_memory_tier(perf_level); - node_set(node, memtier->nodelist); + memtier_node_set(node, memtier); } establish_migration_targets(); mutex_unlock(&memory_tier_lock); @@ -303,12 +331,25 @@ static void init_node_memory_tier(int node) static void clear_node_memory_tier(int node) { - struct memory_tier *memtier; + pg_data_t *pgdat; + struct memory_tier *current_memtier; + + pgdat = NODE_DATA(node); + if (!pgdat) + return; mutex_lock(&memory_tier_lock); - memtier = __node_get_memory_tier(node); - if (memtier) { - node_clear(node, memtier->nodelist); + /* + * Make sure we mark the memtier NULL before we assign the new memory tier + * to the NUMA node. This make sure that anybody looking at NODE_DATA + * finds a NULL memtier or the one which is still valid. + */ + current_memtier = rcu_dereference_check(pgdat->memtier, + lockdep_is_held(&memory_tier_lock)); + rcu_assign_pointer(pgdat->memtier, NULL); + synchronize_rcu(); + if (current_memtier) { + node_clear(node, current_memtier->nodelist); establish_migration_targets(); } mutex_unlock(&memory_tier_lock); @@ -383,6 +424,8 @@ static int __init memory_tier_init(void) if (!node_property->perf_level) node_property->perf_level = default_memtier_perf_level; + + rcu_assign_pointer(NODE_DATA(node)->memtier, memtier); } mutex_unlock(&memory_tier_lock);
Also update different helpes to use NODE_DATA()->memtier. Since node specific memtier can change based on the reassignment of NUMA node to a different memory tiers, accessing NODE_DATA()->memtier needs to happen under an rcu read lock or memory_tier_lock. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> --- include/linux/mmzone.h | 3 ++ mm/memory-tiers.c | 65 +++++++++++++++++++++++++++++++++++------- 2 files changed, 57 insertions(+), 11 deletions(-)