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Message-Id: <1532678637-15079-1-git-send-email-lirongqing@baidu.com>
Date: Fri, 27 Jul 2018 16:03:57 +0800
From: Li RongQing <lirongqing@...du.com>
To: netdev@...r.kernel.org, pshelar@....org
Subject: [PATCH][net-next] openvswitch: eliminate cpu_used_mask from sw_flow
The size of struct cpumask varies with CONFIG_NR_CPUS, some config
CONFIG_NR_CPUS is very larger, like 5120, struct cpumask will take
640 bytes, if there is thousands of flows, it will take lots of
memory
cpu_used_mask has two purposes
1: Assume first cpu as cpu0 which maybe not true; now use
cpumask_first(cpu_possible_mask)
2: when get/clear statistic, reduce the iteratation; but it
is not hot path, so use for_each_possible_cpu
Signed-off-by: Zhang Yu <zhangyu31@...du.com>
Signed-off-by: Li RongQing <lirongqing@...du.com>
---
net/openvswitch/flow.c | 11 +++++------
net/openvswitch/flow.h | 5 ++---
net/openvswitch/flow_table.c | 11 +++++------
3 files changed, 12 insertions(+), 15 deletions(-)
diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index 56b8e7167790..ad580bec00fb 100644
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -85,7 +85,9 @@ void ovs_flow_stats_update(struct sw_flow *flow, __be16 tcp_flags,
if (cpu == 0 && unlikely(flow->stats_last_writer != cpu))
flow->stats_last_writer = cpu;
} else {
- stats = rcu_dereference(flow->stats[0]); /* Pre-allocated. */
+ int cpu1 = cpumask_first(cpu_possible_mask);
+
+ stats = rcu_dereference(flow->stats[cpu1]); /* Pre-allocated. */
spin_lock(&stats->lock);
/* If the current CPU is the only writer on the
@@ -118,7 +120,6 @@ void ovs_flow_stats_update(struct sw_flow *flow, __be16 tcp_flags,
rcu_assign_pointer(flow->stats[cpu],
new_stats);
- cpumask_set_cpu(cpu, &flow->cpu_used_mask);
goto unlock;
}
}
@@ -145,8 +146,7 @@ void ovs_flow_stats_get(const struct sw_flow *flow,
*tcp_flags = 0;
memset(ovs_stats, 0, sizeof(*ovs_stats));
- /* We open code this to make sure cpu 0 is always considered */
- for (cpu = 0; cpu < nr_cpu_ids; cpu = cpumask_next(cpu, &flow->cpu_used_mask)) {
+ for_each_possible_cpu(cpu) {
struct flow_stats *stats = rcu_dereference_ovsl(flow->stats[cpu]);
if (stats) {
@@ -169,8 +169,7 @@ void ovs_flow_stats_clear(struct sw_flow *flow)
{
int cpu;
- /* We open code this to make sure cpu 0 is always considered */
- for (cpu = 0; cpu < nr_cpu_ids; cpu = cpumask_next(cpu, &flow->cpu_used_mask)) {
+ for_each_possible_cpu(cpu) {
struct flow_stats *stats = ovsl_dereference(flow->stats[cpu]);
if (stats) {
diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h
index c670dd24b8b7..d0ea5d6ced3e 100644
--- a/net/openvswitch/flow.h
+++ b/net/openvswitch/flow.h
@@ -223,17 +223,16 @@ struct sw_flow {
u32 hash;
} flow_table, ufid_table;
int stats_last_writer; /* CPU id of the last writer on
- * 'stats[0]'.
+ * 'stats[first cpu id]'.
*/
struct sw_flow_key key;
struct sw_flow_id id;
- struct cpumask cpu_used_mask;
struct sw_flow_mask *mask;
struct sw_flow_actions __rcu *sf_acts;
struct flow_stats __rcu *stats[]; /* One for each CPU. First one
* is allocated at flow creation time,
* the rest are allocated on demand
- * while holding the 'stats[0].lock'.
+ * while holding the 'stats[first cpu id].lock'
*/
};
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index 80ea2a71852e..e4dbd65c308a 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -80,6 +80,7 @@ struct sw_flow *ovs_flow_alloc(void)
{
struct sw_flow *flow;
struct flow_stats *stats;
+ int cpu = cpumask_first(cpu_possible_mask);
flow = kmem_cache_zalloc(flow_cache, GFP_KERNEL);
if (!flow)
@@ -90,15 +91,13 @@ struct sw_flow *ovs_flow_alloc(void)
/* Initialize the default stat node. */
stats = kmem_cache_alloc_node(flow_stats_cache,
GFP_KERNEL | __GFP_ZERO,
- node_online(0) ? 0 : NUMA_NO_NODE);
+ cpu_to_node(cpu));
if (!stats)
goto err;
spin_lock_init(&stats->lock);
- RCU_INIT_POINTER(flow->stats[0], stats);
-
- cpumask_set_cpu(0, &flow->cpu_used_mask);
+ RCU_INIT_POINTER(flow->stats[cpu], stats);
return flow;
err:
@@ -142,11 +141,11 @@ static void flow_free(struct sw_flow *flow)
kfree(flow->id.unmasked_key);
if (flow->sf_acts)
ovs_nla_free_flow_actions((struct sw_flow_actions __force *)flow->sf_acts);
- /* We open code this to make sure cpu 0 is always considered */
- for (cpu = 0; cpu < nr_cpu_ids; cpu = cpumask_next(cpu, &flow->cpu_used_mask))
+ for_each_possible_cpu(cpu) {
if (flow->stats[cpu])
kmem_cache_free(flow_stats_cache,
(struct flow_stats __force *)flow->stats[cpu]);
+ }
kmem_cache_free(flow_cache, flow);
}
--
2.16.2
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