From: Rusty Russell <rusty@rustcorp.com.au>
The cpu handling in net/core/flow.c is complex: it tries to allocate flow
cache as each CPU comes up. It might as well allocate them for each
possible CPU at boot.
---
net/core/flow.c | 81 ++++++++++----------------------------------------------
1 files changed, 15 insertions(+), 66 deletions(-)
diff -puN net/core/flow.c~simplify-flow_c-cpu-handling net/core/flow.c
--- 25/net/core/flow.c~simplify-flow_c-cpu-handling 2004-01-22 00:43:59.000000000 -0800
+++ 25-akpm/net/core/flow.c 2004-01-22 00:43:59.000000000 -0800
@@ -66,24 +66,18 @@ static struct timer_list flow_hash_rnd_t
struct flow_flush_info {
atomic_t cpuleft;
- cpumask_t cpumap;
struct completion completion;
};
static DEFINE_PER_CPU(struct tasklet_struct, flow_flush_tasklets) = { NULL };
#define flow_flush_tasklet(cpu) (&per_cpu(flow_flush_tasklets, cpu))
-static DECLARE_MUTEX(flow_cache_cpu_sem);
-static cpumask_t flow_cache_cpu_map;
-static unsigned int flow_cache_cpu_count;
-
static void flow_cache_new_hashrnd(unsigned long arg)
{
int i;
- for (i = 0; i < NR_CPUS; i++)
- if (cpu_isset(i, flow_cache_cpu_map))
- flow_hash_rnd_recalc(i) = 1;
+ for_each_cpu(i)
+ flow_hash_rnd_recalc(i) = 1;
flow_hash_rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
add_timer(&flow_hash_rnd_timer);
@@ -179,7 +173,9 @@ void *flow_cache_lookup(struct flowi *ke
cpu = smp_processor_id();
fle = NULL;
- if (!cpu_isset(cpu, flow_cache_cpu_map))
+ /* Packet really early in init? Making flow_cache_init a
+ * pre-smp initcall would solve this. --RR */
+ if (!flow_table(cpu))
goto nocache;
if (flow_hash_rnd_recalc(cpu))
@@ -278,8 +274,6 @@ static void flow_cache_flush_per_cpu(voi
struct tasklet_struct *tasklet;
cpu = smp_processor_id();
- if (!cpu_isset(cpu, info->cpumap))
- return;
tasklet = flow_flush_tasklet(cpu);
tasklet->data = (unsigned long)info;
@@ -289,29 +283,23 @@ static void flow_cache_flush_per_cpu(voi
void flow_cache_flush(void)
{
struct flow_flush_info info;
- static DECLARE_MUTEX(flow_flush_sem);
-
- down(&flow_cache_cpu_sem);
- info.cpumap = flow_cache_cpu_map;
- atomic_set(&info.cpuleft, flow_cache_cpu_count);
- up(&flow_cache_cpu_sem);
+ /* Don't want cpus going down or up during this, also protects
+ * against multiple callers. */
+ down(&cpucontrol);
+ atomic_set(&info.cpuleft, num_online_cpus());
init_completion(&info.completion);
- down(&flow_flush_sem);
-
local_bh_disable();
smp_call_function(flow_cache_flush_per_cpu, &info, 1, 0);
- if (cpu_isset(smp_processor_id(), info.cpumap))
- flow_cache_flush_tasklet((unsigned long)&info);
+ flow_cache_flush_tasklet((unsigned long)&info);
local_bh_enable();
wait_for_completion(&info.completion);
-
- up(&flow_flush_sem);
+ up(&cpucontrol);
}
-static int __devinit flow_cache_cpu_prepare(int cpu)
+static void __devinit flow_cache_cpu_prepare(int cpu)
{
struct tasklet_struct *tasklet;
unsigned long order;
@@ -324,9 +312,8 @@ static int __devinit flow_cache_cpu_prep
flow_table(cpu) = (struct flow_cache_entry **)
__get_free_pages(GFP_KERNEL, order);
-
if (!flow_table(cpu))
- return NOTIFY_BAD;
+ panic("NET: failed to allocate flow cache order %lu\n", order);
memset(flow_table(cpu), 0, PAGE_SIZE << order);
@@ -335,39 +322,8 @@ static int __devinit flow_cache_cpu_prep
tasklet = flow_flush_tasklet(cpu);
tasklet_init(tasklet, flow_cache_flush_tasklet, 0);
-
- return NOTIFY_OK;
-}
-
-static int __devinit flow_cache_cpu_online(int cpu)
-{
- down(&flow_cache_cpu_sem);
- cpu_set(cpu, flow_cache_cpu_map);
- flow_cache_cpu_count++;
- up(&flow_cache_cpu_sem);
-
- return NOTIFY_OK;
}
-static int __devinit flow_cache_cpu_notify(struct notifier_block *self,
- unsigned long action, void *hcpu)
-{
- unsigned long cpu = (unsigned long)cpu;
- switch (action) {
- case CPU_UP_PREPARE:
- return flow_cache_cpu_prepare(cpu);
- break;
- case CPU_ONLINE:
- return flow_cache_cpu_online(cpu);
- break;
- }
- return NOTIFY_OK;
-}
-
-static struct notifier_block __devinitdata flow_cache_cpu_nb = {
- .notifier_call = flow_cache_cpu_notify,
-};
-
static int __init flow_cache_init(void)
{
int i;
@@ -389,15 +345,8 @@ static int __init flow_cache_init(void)
flow_hash_rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
add_timer(&flow_hash_rnd_timer);
- register_cpu_notifier(&flow_cache_cpu_nb);
- for (i = 0; i < NR_CPUS; i++) {
- if (!cpu_online(i))
- continue;
- if (flow_cache_cpu_prepare(i) == NOTIFY_OK &&
- flow_cache_cpu_online(i) == NOTIFY_OK)
- continue;
- panic("NET: failed to initialise flow cache hash table\n");
- }
+ for_each_cpu(i)
+ flow_cache_cpu_prepare(i);
return 0;
}
_