diff options
| -rw-r--r-- | net/core/flow.c | 42 |
1 files changed, 39 insertions, 3 deletions
diff --git a/net/core/flow.c b/net/core/flow.c index c56ea6f7f6c7..7fae13537b6b 100644 --- a/net/core/flow.c +++ b/net/core/flow.c @@ -323,6 +323,24 @@ static void flow_cache_flush_tasklet(unsigned long data) complete(&info->completion); } +/* + * Return whether a cpu needs flushing. Conservatively, we assume + * the presence of any entries means the core may require flushing, + * since the flow_cache_ops.check() function may assume it's running + * on the same core as the per-cpu cache component. + */ +static int flow_cache_percpu_empty(struct flow_cache *fc, int cpu) +{ + struct flow_cache_percpu *fcp; + int i; + + fcp = &per_cpu(*fc->percpu, cpu); + for (i = 0; i < flow_cache_hash_size(fc); i++) + if (!hlist_empty(&fcp->hash_table[i])) + return 0; + return 1; +} + static void flow_cache_flush_per_cpu(void *data) { struct flow_flush_info *info = data; @@ -337,22 +355,40 @@ void flow_cache_flush(void) { struct flow_flush_info info; static DEFINE_MUTEX(flow_flush_sem); + cpumask_var_t mask; + int i, self; + + /* Track which cpus need flushing to avoid disturbing all cores. */ + if (!alloc_cpumask_var(&mask, GFP_KERNEL)) + return; + cpumask_clear(mask); /* Don't want cpus going down or up during this. */ get_online_cpus(); mutex_lock(&flow_flush_sem); info.cache = &flow_cache_global; - atomic_set(&info.cpuleft, num_online_cpus()); + for_each_online_cpu(i) + if (!flow_cache_percpu_empty(info.cache, i)) + cpumask_set_cpu(i, mask); + atomic_set(&info.cpuleft, cpumask_weight(mask)); + if (atomic_read(&info.cpuleft) == 0) + goto done; + init_completion(&info.completion); local_bh_disable(); - smp_call_function(flow_cache_flush_per_cpu, &info, 0); - flow_cache_flush_tasklet((unsigned long)&info); + self = cpumask_test_and_clear_cpu(smp_processor_id(), mask); + on_each_cpu_mask(mask, flow_cache_flush_per_cpu, &info, 0); + if (self) + flow_cache_flush_tasklet((unsigned long)&info); local_bh_enable(); wait_for_completion(&info.completion); + +done: mutex_unlock(&flow_flush_sem); put_online_cpus(); + free_cpumask_var(mask); } static void flow_cache_flush_task(struct work_struct *work) |