| Message ID | 20240115045253.1775-4-honggyu.kim@sk.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | DAMON based 2-tier memory management for CXL memory | expand |
On Mon, 15 Jan 2024 13:52:51 +0900 Honggyu Kim <honggyu.kim@sk.com> wrote: > From: Hyeongtak Ji <hyeongtak.ji@sk.com> > > This patch adds next_promotion_node that can be used to identify the > appropriate promotion target based on memory tiers. When multiple > promotion target nodes are available, the nearest node is selected based > on numa distance. > > Signed-off-by: Hyeongtak Ji <hyeongtak.ji@sk.com> > --- > include/linux/memory-tiers.h | 11 +++++++++ > mm/memory-tiers.c | 43 ++++++++++++++++++++++++++++++++++++ > 2 files changed, 54 insertions(+) > > diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h > index 1e39d27bee41..0788e435fc50 100644 > --- a/include/linux/memory-tiers.h > +++ b/include/linux/memory-tiers.h > @@ -50,6 +50,7 @@ int mt_set_default_dram_perf(int nid, struct node_hmem_attrs *perf, > int mt_perf_to_adistance(struct node_hmem_attrs *perf, int *adist); > #ifdef CONFIG_MIGRATION > int next_demotion_node(int node); > +int next_promotion_node(int node); > void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets); > bool node_is_toptier(int node); > #else > @@ -58,6 +59,11 @@ static inline int next_demotion_node(int node) > return NUMA_NO_NODE; > } > > +static inline int next_promotion_node(int node) > +{ > + return NUMA_NO_NODE; > +} > + > static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets) > { > *targets = NODE_MASK_NONE; > @@ -101,6 +107,11 @@ static inline int next_demotion_node(int node) > return NUMA_NO_NODE; > } > > +static inline int next_promotion_node(int node) > +{ > + return NUMA_NO_NODE; > +} > + > static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets) > { > *targets = NODE_MASK_NONE; > diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c > index 8d5291add2bc..0060ee571cf4 100644 > --- a/mm/memory-tiers.c > +++ b/mm/memory-tiers.c > @@ -335,6 +335,49 @@ int next_demotion_node(int node) > return target; > } > > +/* > + * Select a promotion target that is close to the from node among the given > + * two nodes. > + * > + * TODO: consider other decision policy as node_distance may not be precise. > + */ > +static int select_promotion_target(int a, int b, int from) > +{ > + if (node_distance(from, a) < node_distance(from, b)) > + return a; > + else > + return b; > +} > + > +/** > + * next_promotion_node() - Get the next node in the promotion path > + * @node: The starting node to lookup the next node > + * > + * Return: node id for next memory node in the promotion path hierarchy > + * from @node; NUMA_NO_NODE if @node is the toptier. > + */ > +int next_promotion_node(int node) > +{ > + int target = NUMA_NO_NODE; > + int nid; > + > + if (node_is_toptier(node)) > + return NUMA_NO_NODE; > + > + rcu_read_lock(); > + for_each_node_state(nid, N_MEMORY) { > + if (node_isset(node, node_demotion[nid].preferred)) { > + if (target == NUMA_NO_NODE) > + target = nid; > + else > + target = select_promotion_target(nid, target, node); > + } > + } > + rcu_read_unlock(); > + > + return target; > +} > + If this is gonna used by only DAMON and we don't have a concrete plan to making this used by others, I think implementing this in mm/damon/ might make sense. > static void disable_all_demotion_targets(void) > { > struct memory_tier *memtier; > -- > 2.34.1
diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h index 1e39d27bee41..0788e435fc50 100644 --- a/include/linux/memory-tiers.h +++ b/include/linux/memory-tiers.h @@ -50,6 +50,7 @@ int mt_set_default_dram_perf(int nid, struct node_hmem_attrs *perf, int mt_perf_to_adistance(struct node_hmem_attrs *perf, int *adist); #ifdef CONFIG_MIGRATION int next_demotion_node(int node); +int next_promotion_node(int node); void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets); bool node_is_toptier(int node); #else @@ -58,6 +59,11 @@ static inline int next_demotion_node(int node) return NUMA_NO_NODE; } +static inline int next_promotion_node(int node) +{ + return NUMA_NO_NODE; +} + static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets) { *targets = NODE_MASK_NONE; @@ -101,6 +107,11 @@ static inline int next_demotion_node(int node) return NUMA_NO_NODE; } +static inline int next_promotion_node(int node) +{ + return NUMA_NO_NODE; +} + static inline void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets) { *targets = NODE_MASK_NONE; diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index 8d5291add2bc..0060ee571cf4 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -335,6 +335,49 @@ int next_demotion_node(int node) return target; } +/* + * Select a promotion target that is close to the from node among the given + * two nodes. + * + * TODO: consider other decision policy as node_distance may not be precise. + */ +static int select_promotion_target(int a, int b, int from) +{ + if (node_distance(from, a) < node_distance(from, b)) + return a; + else + return b; +} + +/** + * next_promotion_node() - Get the next node in the promotion path + * @node: The starting node to lookup the next node + * + * Return: node id for next memory node in the promotion path hierarchy + * from @node; NUMA_NO_NODE if @node is the toptier. + */ +int next_promotion_node(int node) +{ + int target = NUMA_NO_NODE; + int nid; + + if (node_is_toptier(node)) + return NUMA_NO_NODE; + + rcu_read_lock(); + for_each_node_state(nid, N_MEMORY) { + if (node_isset(node, node_demotion[nid].preferred)) { + if (target == NUMA_NO_NODE) + target = nid; + else + target = select_promotion_target(nid, target, node); + } + } + rcu_read_unlock(); + + return target; +} + static void disable_all_demotion_targets(void) { struct memory_tier *memtier;