On 7/21/26 5:33 AM, Gregory Price wrote: > find_next_best_node() picks the next-closest node for a fallback list > from the full N_MEMORY set. Refactor it into find_next_best_node_in(), > which takes an explicit candidates nodemask. > > This enables building fallback lists with non-N_MEMORY candidates. > > No functional change: every caller still selects from N_MEMORY. > > Signed-off-by: Gregory Price <[email protected]> > --- > mm/internal.h | 6 ++++-- > mm/memory-tiers.c | 7 ++++--- > mm/page_alloc.c | 13 ++++++++----- > 3 files changed, 16 insertions(+), 10 deletions(-) > > diff --git a/mm/internal.h b/mm/internal.h > index f26423de4ca28..96d78a7778e88 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -1103,7 +1103,8 @@ extern int node_reclaim_mode; > > extern unsigned long node_reclaim(struct pglist_data *pgdat, > gfp_t gfp_mask, unsigned int order); > -extern int find_next_best_node(int node, nodemask_t *used_node_mask); > +extern int find_next_best_node_in(int node, nodemask_t *used_node_mask, > + const nodemask_t *candidates); > #else > #define node_reclaim_mode 0 > > @@ -1112,7 +1113,8 @@ static inline unsigned long node_reclaim(struct > pglist_data *pgdat, > { > return 0; > } > -static inline int find_next_best_node(int node, nodemask_t *used_node_mask) > +static inline int find_next_best_node_in(int node, nodemask_t > *used_node_mask, > + const nodemask_t *candidates) > { > return NUMA_NO_NODE; > } > diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c > index 54851d8a195b0..25e121851b586 100644 > --- a/mm/memory-tiers.c > +++ b/mm/memory-tiers.c > @@ -370,7 +370,7 @@ int next_demotion_node(int node, const nodemask_t > *allowed_mask) > * closest demotion target. > */ > nodes_complement(mask, *allowed_mask); > - return find_next_best_node(node, &mask); > + return find_next_best_node_in(node, &mask, &node_states[N_MEMORY]); > } > > static void disable_all_demotion_targets(void) > @@ -450,7 +450,7 @@ static void establish_demotion_targets(void) > memtier = list_next_entry(memtier, list); > tier_nodes = get_memtier_nodemask(memtier); > /* > - * find_next_best_node, use 'used' nodemask as a skip list. > + * find_next_best_node_in, use 'used' nodemask as a skip list. > * Add all memory nodes except the selected memory tier > * nodelist to skip list so that we find the best node from the > * memtier nodelist. > @@ -463,7 +463,8 @@ static void establish_demotion_targets(void) > * in the preferred mask when allocating pages during demotion. > */ > do { > - target = find_next_best_node(node, &tier_nodes); > + target = find_next_best_node_in(node, &tier_nodes, > + &node_states[N_MEMORY]); > if (target == NUMA_NO_NODE) > break; > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index f93a6bb9a872d..acf096f525f49 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -5743,9 +5743,10 @@ static int numa_zonelist_order_handler(const struct > ctl_table *table, int write, > static int node_load[MAX_NUMNODES]; > > /** > - * find_next_best_node - find the next node that should appear in a given > node's fallback list > + * find_next_best_node_in - find the next node that should appear in a given > node's fallback list > * @node: node whose fallback list we're appending > * @used_node_mask: nodemask_t of already used nodes > + * @candidates: nodemask_t of nodes eligible for selection > * > * We use a number of factors to determine which is the next node that should > * appear on a given node's fallback list. The node should not have appeared > @@ -5757,7 +5758,8 @@ static int node_load[MAX_NUMNODES]; > * > * Return: node id of the found node or %NUMA_NO_NODE if no node is found. > */ > -int find_next_best_node(int node, nodemask_t *used_node_mask) > +int find_next_best_node_in(int node, nodemask_t *used_node_mask, > + const nodemask_t *candidates) > { > int n, val; > int min_val = INT_MAX; > @@ -5767,12 +5769,12 @@ int find_next_best_node(int node, nodemask_t > *used_node_mask) > * Use the local node if we haven't already, but for memoryless local > * node, we should skip it and fall back to other nodes. > */ > - if (!node_isset(node, *used_node_mask) && node_state(node, N_MEMORY)) { > + if (!node_isset(node, *used_node_mask) && node_isset(node, > *candidates)) { > node_set(node, *used_node_mask); > return node; > } > > - for_each_node_state(n, N_MEMORY) { > + for_each_node_mask(n, *candidates) { > > /* Don't want a node to appear more than once */ > if (node_isset(n, *used_node_mask)) > @@ -5857,7 +5859,8 @@ static void build_zonelists(pg_data_t *pgdat) > prev_node = local_node; > > memset(node_order, 0, sizeof(node_order)); > - while ((node = find_next_best_node(local_node, &used_mask)) >= 0) { > + while ((node = find_next_best_node_in(local_node, &used_mask, > + &node_states[N_MEMORY])) >= 0) { > /* > * We don't want to pressure a particular node. > * So adding penalty to the first node in same
Looks good! Acked-by: Balbir Singh <[email protected]>
