Use actual CPU number instead of hardcoded value to decide the size
of 'cpu_used_mask' in 'struct sw_flow'. Below is the reason.
'struct cpumask cpu_used_mask' is embedded in struct sw_flow.
Its size is hardcoded to CONFIG_NR_CPUS bits, which can be
8192 by default, it costs memory and slows down ovs_flow_alloc
To address this:
Redefine cpu_used_mask to pointer.
Append cpumask_size() bytes after 'stat' to hold cpumask.
Initialization cpu_used_mask right after stats_last_writer.
APIs like cpumask_next and cpumask_set_cpu never access bits
beyond cpu count, cpumask_size() bytes of memory is enough
Signed-off-by: Eddy Tao <[email protected]>
---
net/openvswitch/flow.c | 9 ++++++---
net/openvswitch/flow.h | 2 +-
net/openvswitch/flow_table.c | 8 +++++---
3 files changed, 12 insertions(+), 7 deletions(-)
diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index e20d1a973417..416976f70322 100644
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -107,7 +107,8 @@ 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);
+ cpumask_set_cpu(cpu,
+ flow->cpu_used_mask);
goto unlock;
}
}
@@ -135,7 +136,8 @@ void ovs_flow_stats_get(const struct sw_flow *flow,
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 (cpu = 0; cpu < nr_cpu_ids;
+ cpu = cpumask_next(cpu, flow->cpu_used_mask)) {
struct sw_flow_stats *stats = rcu_dereference_ovsl(flow->stats[cpu]);
if (stats) {
@@ -159,7 +161,8 @@ 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 (cpu = 0; cpu < nr_cpu_ids;
+ cpu = cpumask_next(cpu, flow->cpu_used_mask)) {
struct sw_flow_stats *stats = ovsl_dereference(flow->stats[cpu]);
if (stats) {
diff --git a/net/openvswitch/flow.h b/net/openvswitch/flow.h
index 073ab73ffeaa..b5711aff6e76 100644
--- a/net/openvswitch/flow.h
+++ b/net/openvswitch/flow.h
@@ -229,7 +229,7 @@ struct sw_flow {
*/
struct sw_flow_key key;
struct sw_flow_id id;
- struct cpumask cpu_used_mask;
+ struct cpumask *cpu_used_mask;
struct sw_flow_mask *mask;
struct sw_flow_actions __rcu *sf_acts;
struct sw_flow_stats __rcu *stats[]; /* One for each CPU. First one
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index 0a0e4c283f02..791504b7f42b 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -79,6 +79,7 @@ struct sw_flow *ovs_flow_alloc(void)
return ERR_PTR(-ENOMEM);
flow->stats_last_writer = -1;
+ flow->cpu_used_mask = (struct cpumask *)&flow->stats[nr_cpu_ids];
/* Initialize the default stat node. */
stats = kmem_cache_alloc_node(flow_stats_cache,
@@ -91,7 +92,7 @@ struct sw_flow *ovs_flow_alloc(void)
RCU_INIT_POINTER(flow->stats[0], stats);
- cpumask_set_cpu(0, &flow->cpu_used_mask);
+ cpumask_set_cpu(0, flow->cpu_used_mask);
return flow;
err:
@@ -115,7 +116,7 @@ static void flow_free(struct sw_flow *flow)
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)) {
+ cpu = cpumask_next(cpu, flow->cpu_used_mask)) {
if (flow->stats[cpu])
kmem_cache_free(flow_stats_cache,
(struct sw_flow_stats __force *)flow->stats[cpu]);
@@ -1196,7 +1197,8 @@ int ovs_flow_init(void)
flow_cache = kmem_cache_create("sw_flow", sizeof(struct sw_flow)
+ (nr_cpu_ids
- * sizeof(struct sw_flow_stats *)),
+ * sizeof(struct sw_flow_stats *))
+ + cpumask_size(),
0, 0, NULL);
if (flow_cache == NULL)
return -ENOMEM;
--
2.27.0
On Fri, Feb 03, 2023 at 11:42:45PM +0800, Eddy Tao wrote:
> Use actual CPU number instead of hardcoded value to decide the size
> of 'cpu_used_mask' in 'struct sw_flow'. Below is the reason.
>
> 'struct cpumask cpu_used_mask' is embedded in struct sw_flow.
> Its size is hardcoded to CONFIG_NR_CPUS bits, which can be
> 8192 by default, it costs memory and slows down ovs_flow_alloc
>
> To address this:
> Redefine cpu_used_mask to pointer.
> Append cpumask_size() bytes after 'stat' to hold cpumask.
> Initialization cpu_used_mask right after stats_last_writer.
>
> APIs like cpumask_next and cpumask_set_cpu never access bits
> beyond cpu count, cpumask_size() bytes of memory is enough
>
> Signed-off-by: Eddy Tao <[email protected]>
nit: I think the correct prefix for the patch subject is 'openvswitch:'
And there should be a space after the prefix.
[PATCH net-next v8 1/1] openvswitch: reduce cpu_used_mask
Hi, Simon:
Thank you for the time on the review.
and i looked into net folder and get various results
'net:', 'net: gre:', 'net: bridge:', 'net: thunderx', 'net: sock', 'net:
genetlink', and there is also examples as you suggested like 'devlink:'
similarly, in other folders i see similar inconsistency, mm folder is an
example.
I turned below links and did not find item regarding to the prefix
definition
Link: https://docs.kernel.org/process/maintainer-netdev.html
Link:
https://docs.kernel.org/process/submitting-patches.html#submittingpatches
Going through the git log in file net/openvswitch/flow.c, the 'net:
openvswitch: ' prefix were used in previous commits.
I think the fix contained 'net' keep the prefix from name collision and
better keeps it consistent with its neighbors in the same file
And yes, there should be a blank space after the colon, i miss it, will
update the revision, after we nail down the wording of the prefix.
Thanks
eddy
On 2023/2/4 21:28, Simon Horman wrote:
> nit: I think the correct prefix for the patch subject is 'openvswitch:'
> And there should be a space after the prefix.
>
> [PATCH net-next v8 1/1] openvswitch: reduce cpu_used_mask