lib: objagg: implement optimization hints assembly and use hints for object creation
Implement simple greedy algo to find more optimized root-delta tree for
a given objagg instance. This "hints" can be used by a driver to:
1) check if the hints are better (driver's choice) than the original
objagg tree. Driver does comparison of objagg stats and hints stats.
2) use the hints to create a new objagg instance which will construct
the root-delta tree according to the passed hints. Currently, only a
simple greedy algorithm is implemented. Basically it finds the roots
according to the maximal possible user count including deltas.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/lib/objagg.c b/lib/objagg.c
index dae390b..befe8a4 100644
--- a/lib/objagg.c
+++ b/lib/objagg.c
@@ -4,6 +4,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/rhashtable.h>
+#include <linux/idr.h>
#include <linux/list.h>
#include <linux/sort.h>
#include <linux/objagg.h>
@@ -11,6 +12,34 @@
#define CREATE_TRACE_POINTS
#include <trace/events/objagg.h>
+struct objagg_hints {
+ struct rhashtable node_ht;
+ struct rhashtable_params ht_params;
+ struct list_head node_list;
+ unsigned int node_count;
+ unsigned int root_count;
+ unsigned int refcount;
+ const struct objagg_ops *ops;
+};
+
+struct objagg_hints_node {
+ struct rhash_head ht_node; /* member of objagg_hints->node_ht */
+ struct list_head list; /* member of objagg_hints->node_list */
+ struct objagg_hints_node *parent;
+ unsigned int root_id;
+ struct objagg_obj_stats_info stats_info;
+ unsigned long obj[0];
+};
+
+static struct objagg_hints_node *
+objagg_hints_lookup(struct objagg_hints *objagg_hints, void *obj)
+{
+ if (!objagg_hints)
+ return NULL;
+ return rhashtable_lookup_fast(&objagg_hints->node_ht, obj,
+ objagg_hints->ht_params);
+}
+
struct objagg {
const struct objagg_ops *ops;
void *priv;
@@ -18,6 +47,8 @@ struct objagg {
struct rhashtable_params ht_params;
struct list_head obj_list;
unsigned int obj_count;
+ struct ida root_ida;
+ struct objagg_hints *hints;
};
struct objagg_obj {
@@ -30,6 +61,7 @@ struct objagg_obj {
void *delta_priv; /* user delta private */
void *root_priv; /* user root private */
};
+ unsigned int root_id;
unsigned int refcount; /* counts number of users of this object
* including nested objects
*/
@@ -130,7 +162,8 @@ static struct objagg_obj *objagg_obj_lookup(struct objagg *objagg, void *obj)
static int objagg_obj_parent_assign(struct objagg *objagg,
struct objagg_obj *objagg_obj,
- struct objagg_obj *parent)
+ struct objagg_obj *parent,
+ bool take_parent_ref)
{
void *delta_priv;
@@ -144,7 +177,8 @@ static int objagg_obj_parent_assign(struct objagg *objagg,
*/
objagg_obj->parent = parent;
objagg_obj->delta_priv = delta_priv;
- objagg_obj_ref_inc(objagg_obj->parent);
+ if (take_parent_ref)
+ objagg_obj_ref_inc(objagg_obj->parent);
trace_objagg_obj_parent_assign(objagg, objagg_obj,
parent,
parent->refcount);
@@ -164,7 +198,7 @@ static int objagg_obj_parent_lookup_assign(struct objagg *objagg,
if (!objagg_obj_is_root(objagg_obj_cur))
continue;
err = objagg_obj_parent_assign(objagg, objagg_obj,
- objagg_obj_cur);
+ objagg_obj_cur, true);
if (!err)
return 0;
}
@@ -184,16 +218,68 @@ static void objagg_obj_parent_unassign(struct objagg *objagg,
__objagg_obj_put(objagg, objagg_obj->parent);
}
-static int objagg_obj_root_create(struct objagg *objagg,
- struct objagg_obj *objagg_obj)
+static int objagg_obj_root_id_alloc(struct objagg *objagg,
+ struct objagg_obj *objagg_obj,
+ struct objagg_hints_node *hnode)
{
- objagg_obj->root_priv = objagg->ops->root_create(objagg->priv,
- objagg_obj->obj);
- if (IS_ERR(objagg_obj->root_priv))
- return PTR_ERR(objagg_obj->root_priv);
+ unsigned int min, max;
+ int root_id;
+ /* In case there are no hints available, the root id is invalid. */
+ if (!objagg->hints) {
+ objagg_obj->root_id = OBJAGG_OBJ_ROOT_ID_INVALID;
+ return 0;
+ }
+
+ if (hnode) {
+ min = hnode->root_id;
+ max = hnode->root_id;
+ } else {
+ /* For objects with no hint, start after the last
+ * hinted root_id.
+ */
+ min = objagg->hints->root_count;
+ max = ~0;
+ }
+
+ root_id = ida_alloc_range(&objagg->root_ida, min, max, GFP_KERNEL);
+
+ if (root_id < 0)
+ return root_id;
+ objagg_obj->root_id = root_id;
+ return 0;
+}
+
+static void objagg_obj_root_id_free(struct objagg *objagg,
+ struct objagg_obj *objagg_obj)
+{
+ if (!objagg->hints)
+ return;
+ ida_free(&objagg->root_ida, objagg_obj->root_id);
+}
+
+static int objagg_obj_root_create(struct objagg *objagg,
+ struct objagg_obj *objagg_obj,
+ struct objagg_hints_node *hnode)
+{
+ int err;
+
+ err = objagg_obj_root_id_alloc(objagg, objagg_obj, hnode);
+ if (err)
+ return err;
+ objagg_obj->root_priv = objagg->ops->root_create(objagg->priv,
+ objagg_obj->obj,
+ objagg_obj->root_id);
+ if (IS_ERR(objagg_obj->root_priv)) {
+ err = PTR_ERR(objagg_obj->root_priv);
+ goto err_root_create;
+ }
trace_objagg_obj_root_create(objagg, objagg_obj);
return 0;
+
+err_root_create:
+ objagg_obj_root_id_free(objagg, objagg_obj);
+ return err;
}
static void objagg_obj_root_destroy(struct objagg *objagg,
@@ -201,19 +287,69 @@ static void objagg_obj_root_destroy(struct objagg *objagg,
{
trace_objagg_obj_root_destroy(objagg, objagg_obj);
objagg->ops->root_destroy(objagg->priv, objagg_obj->root_priv);
+ objagg_obj_root_id_free(objagg, objagg_obj);
+}
+
+static struct objagg_obj *__objagg_obj_get(struct objagg *objagg, void *obj);
+
+static int objagg_obj_init_with_hints(struct objagg *objagg,
+ struct objagg_obj *objagg_obj,
+ bool *hint_found)
+{
+ struct objagg_hints_node *hnode;
+ struct objagg_obj *parent;
+ int err;
+
+ hnode = objagg_hints_lookup(objagg->hints, objagg_obj->obj);
+ if (!hnode) {
+ *hint_found = false;
+ return 0;
+ }
+ *hint_found = true;
+
+ if (!hnode->parent)
+ return objagg_obj_root_create(objagg, objagg_obj, hnode);
+
+ parent = __objagg_obj_get(objagg, hnode->parent->obj);
+ if (IS_ERR(parent))
+ return PTR_ERR(parent);
+
+ err = objagg_obj_parent_assign(objagg, objagg_obj, parent, false);
+ if (err) {
+ *hint_found = false;
+ err = 0;
+ goto err_parent_assign;
+ }
+
+ return 0;
+
+err_parent_assign:
+ objagg_obj_put(objagg, parent);
+ return err;
}
static int objagg_obj_init(struct objagg *objagg,
struct objagg_obj *objagg_obj)
{
+ bool hint_found;
int err;
+ /* First, try to use hints if they are available and
+ * if they provide result.
+ */
+ err = objagg_obj_init_with_hints(objagg, objagg_obj, &hint_found);
+ if (err)
+ return err;
+
+ if (hint_found)
+ return 0;
+
/* Try to find if the object can be aggregated under an existing one. */
err = objagg_obj_parent_lookup_assign(objagg, objagg_obj);
if (!err)
return 0;
/* If aggregation is not possible, make the object a root. */
- return objagg_obj_root_create(objagg, objagg_obj);
+ return objagg_obj_root_create(objagg, objagg_obj, NULL);
}
static void objagg_obj_fini(struct objagg *objagg,
@@ -349,8 +485,9 @@ EXPORT_SYMBOL(objagg_obj_put);
/**
* objagg_create - creates a new objagg instance
- * @ops: user-specific callbacks
- * @priv: pointer to a private data passed to the ops
+ * @ops: user-specific callbacks
+ * @objagg_hints: hints, can be NULL
+ * @priv: pointer to a private data passed to the ops
*
* Note: all locking must be provided by the caller.
*
@@ -374,18 +511,25 @@ EXPORT_SYMBOL(objagg_obj_put);
* Returns a pointer to newly created objagg instance in case of success,
* otherwise it returns pointer error using ERR_PTR macro.
*/
-struct objagg *objagg_create(const struct objagg_ops *ops, void *priv)
+struct objagg *objagg_create(const struct objagg_ops *ops,
+ struct objagg_hints *objagg_hints, void *priv)
{
struct objagg *objagg;
int err;
if (WARN_ON(!ops || !ops->root_create || !ops->root_destroy ||
- !ops->delta_create || !ops->delta_destroy))
+ !ops->delta_check || !ops->delta_create ||
+ !ops->delta_destroy))
return ERR_PTR(-EINVAL);
+
objagg = kzalloc(sizeof(*objagg), GFP_KERNEL);
if (!objagg)
return ERR_PTR(-ENOMEM);
objagg->ops = ops;
+ if (objagg_hints) {
+ objagg->hints = objagg_hints;
+ objagg_hints->refcount++;
+ }
objagg->priv = priv;
INIT_LIST_HEAD(&objagg->obj_list);
@@ -397,6 +541,8 @@ struct objagg *objagg_create(const struct objagg_ops *ops, void *priv)
if (err)
goto err_rhashtable_init;
+ ida_init(&objagg->root_ida);
+
trace_objagg_create(objagg);
return objagg;
@@ -415,8 +561,11 @@ EXPORT_SYMBOL(objagg_create);
void objagg_destroy(struct objagg *objagg)
{
trace_objagg_destroy(objagg);
+ ida_destroy(&objagg->root_ida);
WARN_ON(!list_empty(&objagg->obj_list));
rhashtable_destroy(&objagg->obj_ht);
+ if (objagg->hints)
+ objagg_hints_put(objagg->hints);
kfree(objagg);
}
EXPORT_SYMBOL(objagg_destroy);
@@ -496,6 +645,404 @@ void objagg_stats_put(const struct objagg_stats *objagg_stats)
}
EXPORT_SYMBOL(objagg_stats_put);
+static struct objagg_hints_node *
+objagg_hints_node_create(struct objagg_hints *objagg_hints,
+ struct objagg_obj *objagg_obj, size_t obj_size,
+ struct objagg_hints_node *parent_hnode)
+{
+ unsigned int user_count = objagg_obj->stats.user_count;
+ struct objagg_hints_node *hnode;
+ int err;
+
+ hnode = kzalloc(sizeof(*hnode) + obj_size, GFP_KERNEL);
+ if (!hnode)
+ return ERR_PTR(-ENOMEM);
+ memcpy(hnode->obj, &objagg_obj->obj, obj_size);
+ hnode->stats_info.stats.user_count = user_count;
+ hnode->stats_info.stats.delta_user_count = user_count;
+ if (parent_hnode) {
+ parent_hnode->stats_info.stats.delta_user_count += user_count;
+ } else {
+ hnode->root_id = objagg_hints->root_count++;
+ hnode->stats_info.is_root = true;
+ }
+ hnode->stats_info.objagg_obj = objagg_obj;
+
+ err = rhashtable_insert_fast(&objagg_hints->node_ht, &hnode->ht_node,
+ objagg_hints->ht_params);
+ if (err)
+ goto err_ht_insert;
+
+ list_add(&hnode->list, &objagg_hints->node_list);
+ hnode->parent = parent_hnode;
+ objagg_hints->node_count++;
+
+ return hnode;
+
+err_ht_insert:
+ kfree(hnode);
+ return ERR_PTR(err);
+}
+
+static void objagg_hints_flush(struct objagg_hints *objagg_hints)
+{
+ struct objagg_hints_node *hnode, *tmp;
+
+ list_for_each_entry_safe(hnode, tmp, &objagg_hints->node_list, list) {
+ list_del(&hnode->list);
+ rhashtable_remove_fast(&objagg_hints->node_ht, &hnode->ht_node,
+ objagg_hints->ht_params);
+ kfree(hnode);
+ }
+}
+
+struct objagg_tmp_node {
+ struct objagg_obj *objagg_obj;
+ bool crossed_out;
+};
+
+struct objagg_tmp_graph {
+ struct objagg_tmp_node *nodes;
+ unsigned long nodes_count;
+ unsigned long *edges;
+};
+
+static int objagg_tmp_graph_edge_index(struct objagg_tmp_graph *graph,
+ int parent_index, int index)
+{
+ return index * graph->nodes_count + parent_index;
+}
+
+static void objagg_tmp_graph_edge_set(struct objagg_tmp_graph *graph,
+ int parent_index, int index)
+{
+ int edge_index = objagg_tmp_graph_edge_index(graph, index,
+ parent_index);
+
+ __set_bit(edge_index, graph->edges);
+}
+
+static bool objagg_tmp_graph_is_edge(struct objagg_tmp_graph *graph,
+ int parent_index, int index)
+{
+ int edge_index = objagg_tmp_graph_edge_index(graph, index,
+ parent_index);
+
+ return test_bit(edge_index, graph->edges);
+}
+
+static unsigned int objagg_tmp_graph_node_weight(struct objagg_tmp_graph *graph,
+ unsigned int index)
+{
+ struct objagg_tmp_node *node = &graph->nodes[index];
+ unsigned int weight = node->objagg_obj->stats.user_count;
+ int j;
+
+ /* Node weight is sum of node users and all other nodes users
+ * that this node can represent with delta.
+ */
+
+ if (node->crossed_out)
+ return 0;
+ for (j = 0; j < graph->nodes_count; j++) {
+ if (!objagg_tmp_graph_is_edge(graph, index, j))
+ continue;
+ node = &graph->nodes[j];
+ if (node->crossed_out)
+ continue;
+ weight += node->objagg_obj->stats.user_count;
+ }
+ return weight;
+}
+
+static int objagg_tmp_graph_node_max_weight(struct objagg_tmp_graph *graph)
+{
+ unsigned int max_weight = 0;
+ unsigned int weight;
+ int max_index = -1;
+ int i;
+
+ for (i = 0; i < graph->nodes_count; i++) {
+ weight = objagg_tmp_graph_node_weight(graph, i);
+ if (weight > max_weight) {
+ max_weight = weight;
+ max_index = i;
+ }
+ }
+ return max_index;
+}
+
+static struct objagg_tmp_graph *objagg_tmp_graph_create(struct objagg *objagg)
+{
+ unsigned int nodes_count = objagg->obj_count;
+ struct objagg_tmp_graph *graph;
+ struct objagg_tmp_node *node;
+ struct objagg_tmp_node *pnode;
+ struct objagg_obj *objagg_obj;
+ size_t alloc_size;
+ int i, j;
+
+ graph = kzalloc(sizeof(*graph), GFP_KERNEL);
+ if (!graph)
+ return NULL;
+
+ graph->nodes = kcalloc(nodes_count, sizeof(*graph->nodes), GFP_KERNEL);
+ if (!graph->nodes)
+ goto err_nodes_alloc;
+ graph->nodes_count = nodes_count;
+
+ alloc_size = BITS_TO_LONGS(nodes_count * nodes_count) *
+ sizeof(unsigned long);
+ graph->edges = kzalloc(alloc_size, GFP_KERNEL);
+ if (!graph->edges)
+ goto err_edges_alloc;
+
+ i = 0;
+ list_for_each_entry(objagg_obj, &objagg->obj_list, list) {
+ node = &graph->nodes[i++];
+ node->objagg_obj = objagg_obj;
+ }
+
+ /* Assemble a temporary graph. Insert edge X->Y in case Y can be
+ * in delta of X.
+ */
+ for (i = 0; i < nodes_count; i++) {
+ for (j = 0; j < nodes_count; j++) {
+ if (i == j)
+ continue;
+ pnode = &graph->nodes[i];
+ node = &graph->nodes[j];
+ if (objagg->ops->delta_check(objagg->priv,
+ pnode->objagg_obj->obj,
+ node->objagg_obj->obj)) {
+ objagg_tmp_graph_edge_set(graph, i, j);
+
+ }
+ }
+ }
+ return graph;
+
+err_edges_alloc:
+ kfree(graph->nodes);
+err_nodes_alloc:
+ kfree(graph);
+ return NULL;
+}
+
+static void objagg_tmp_graph_destroy(struct objagg_tmp_graph *graph)
+{
+ kfree(graph->edges);
+ kfree(graph->nodes);
+ kfree(graph);
+}
+
+static int
+objagg_opt_simple_greedy_fillup_hints(struct objagg_hints *objagg_hints,
+ struct objagg *objagg)
+{
+ struct objagg_hints_node *hnode, *parent_hnode;
+ struct objagg_tmp_graph *graph;
+ struct objagg_tmp_node *node;
+ int index;
+ int j;
+ int err;
+
+ graph = objagg_tmp_graph_create(objagg);
+ if (!graph)
+ return -ENOMEM;
+
+ /* Find the nodes from the ones that can accommodate most users
+ * and cross them out of the graph. Save them to the hint list.
+ */
+ while ((index = objagg_tmp_graph_node_max_weight(graph)) != -1) {
+ node = &graph->nodes[index];
+ node->crossed_out = true;
+ hnode = objagg_hints_node_create(objagg_hints,
+ node->objagg_obj,
+ objagg->ops->obj_size,
+ NULL);
+ if (IS_ERR(hnode)) {
+ err = PTR_ERR(hnode);
+ goto out;
+ }
+ parent_hnode = hnode;
+ for (j = 0; j < graph->nodes_count; j++) {
+ if (!objagg_tmp_graph_is_edge(graph, index, j))
+ continue;
+ node = &graph->nodes[j];
+ if (node->crossed_out)
+ continue;
+ node->crossed_out = true;
+ hnode = objagg_hints_node_create(objagg_hints,
+ node->objagg_obj,
+ objagg->ops->obj_size,
+ parent_hnode);
+ if (IS_ERR(hnode)) {
+ err = PTR_ERR(hnode);
+ goto out;
+ }
+ }
+ }
+
+ err = 0;
+out:
+ objagg_tmp_graph_destroy(graph);
+ return err;
+}
+
+struct objagg_opt_algo {
+ int (*fillup_hints)(struct objagg_hints *objagg_hints,
+ struct objagg *objagg);
+};
+
+static const struct objagg_opt_algo objagg_opt_simple_greedy = {
+ .fillup_hints = objagg_opt_simple_greedy_fillup_hints,
+};
+
+
+static const struct objagg_opt_algo *objagg_opt_algos[] = {
+ [OBJAGG_OPT_ALGO_SIMPLE_GREEDY] = &objagg_opt_simple_greedy,
+};
+
+static int objagg_hints_obj_cmp(struct rhashtable_compare_arg *arg,
+ const void *obj)
+{
+ struct rhashtable *ht = arg->ht;
+ struct objagg_hints *objagg_hints =
+ container_of(ht, struct objagg_hints, node_ht);
+ const struct objagg_ops *ops = objagg_hints->ops;
+ const char *ptr = obj;
+
+ ptr += ht->p.key_offset;
+ return ops->hints_obj_cmp ? ops->hints_obj_cmp(ptr, arg->key) :
+ memcmp(ptr, arg->key, ht->p.key_len);
+}
+
+/**
+ * objagg_hints_get - obtains hints instance
+ * @objagg: objagg instance
+ * @opt_algo_type: type of hints finding algorithm
+ *
+ * Note: all locking must be provided by the caller.
+ *
+ * According to the algo type, the existing objects of objagg instance
+ * are going to be went-through to assemble an optimal tree. We call this
+ * tree hints. These hints can be later on used for creation of
+ * a new objagg instance. There, the future object creations are going
+ * to be consulted with these hints in order to find out, where exactly
+ * the new object should be put as a root or delta.
+ *
+ * Returns a pointer to hints instance in case of success,
+ * otherwise it returns pointer error using ERR_PTR macro.
+ */
+struct objagg_hints *objagg_hints_get(struct objagg *objagg,
+ enum objagg_opt_algo_type opt_algo_type)
+{
+ const struct objagg_opt_algo *algo = objagg_opt_algos[opt_algo_type];
+ struct objagg_hints *objagg_hints;
+ int err;
+
+ objagg_hints = kzalloc(sizeof(*objagg_hints), GFP_KERNEL);
+ if (!objagg_hints)
+ return ERR_PTR(-ENOMEM);
+
+ objagg_hints->ops = objagg->ops;
+ objagg_hints->refcount = 1;
+
+ INIT_LIST_HEAD(&objagg_hints->node_list);
+
+ objagg_hints->ht_params.key_len = objagg->ops->obj_size;
+ objagg_hints->ht_params.key_offset =
+ offsetof(struct objagg_hints_node, obj);
+ objagg_hints->ht_params.head_offset =
+ offsetof(struct objagg_hints_node, ht_node);
+ objagg_hints->ht_params.obj_cmpfn = objagg_hints_obj_cmp;
+
+ err = rhashtable_init(&objagg_hints->node_ht, &objagg_hints->ht_params);
+ if (err)
+ goto err_rhashtable_init;
+
+ err = algo->fillup_hints(objagg_hints, objagg);
+ if (err)
+ goto err_fillup_hints;
+
+ if (WARN_ON(objagg_hints->node_count != objagg->obj_count))
+ goto err_node_count_check;
+
+ return objagg_hints;
+
+err_node_count_check:
+err_fillup_hints:
+ objagg_hints_flush(objagg_hints);
+ rhashtable_destroy(&objagg_hints->node_ht);
+err_rhashtable_init:
+ kfree(objagg_hints);
+ return ERR_PTR(err);
+}
+EXPORT_SYMBOL(objagg_hints_get);
+
+/**
+ * objagg_hints_put - puts hints instance
+ * @objagg_hints: objagg hints instance
+ *
+ * Note: all locking must be provided by the caller.
+ */
+void objagg_hints_put(struct objagg_hints *objagg_hints)
+{
+ if (--objagg_hints->refcount)
+ return;
+ objagg_hints_flush(objagg_hints);
+ rhashtable_destroy(&objagg_hints->node_ht);
+ kfree(objagg_hints);
+}
+EXPORT_SYMBOL(objagg_hints_put);
+
+/**
+ * objagg_hints_stats_get - obtains stats of the hints instance
+ * @objagg_hints: hints instance
+ *
+ * Note: all locking must be provided by the caller.
+ *
+ * The returned structure contains statistics of all objects
+ * currently in use, ordered by following rules:
+ * 1) Root objects are always on lower indexes than the rest.
+ * 2) Objects with higher delta user count are always on lower
+ * indexes.
+ * 3) In case multiple objects have the same delta user count,
+ * the objects are ordered by user count.
+ *
+ * Returns a pointer to stats instance in case of success,
+ * otherwise it returns pointer error using ERR_PTR macro.
+ */
+const struct objagg_stats *
+objagg_hints_stats_get(struct objagg_hints *objagg_hints)
+{
+ struct objagg_stats *objagg_stats;
+ struct objagg_hints_node *hnode;
+ int i;
+
+ objagg_stats = kzalloc(struct_size(objagg_stats, stats_info,
+ objagg_hints->node_count),
+ GFP_KERNEL);
+ if (!objagg_stats)
+ return ERR_PTR(-ENOMEM);
+
+ i = 0;
+ list_for_each_entry(hnode, &objagg_hints->node_list, list) {
+ memcpy(&objagg_stats->stats_info[i], &hnode->stats_info,
+ sizeof(objagg_stats->stats_info[0]));
+ i++;
+ }
+ objagg_stats->stats_info_count = i;
+
+ sort(objagg_stats->stats_info, objagg_stats->stats_info_count,
+ sizeof(struct objagg_obj_stats_info),
+ objagg_stats_info_sort_cmp_func, NULL);
+
+ return objagg_stats;
+}
+EXPORT_SYMBOL(objagg_hints_stats_get);
+
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Jiri Pirko <jiri@mellanox.com>");
MODULE_DESCRIPTION("Object aggregation manager");