flow: structurize flow cache
Group all per-cpu data to one structure instead of having many
globals. Also prepare the internals so that we can have multiple
instances of the flow cache if needed.
Only the kmem_cache is left as a global as all flow caches share
the same element size, and benefit from using a common cache.
Signed-off-by: Timo Teras <timo.teras@iki.fi>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/flow.c b/net/core/flow.c
index 9601587..1d27ca6 100644
--- a/net/core/flow.c
+++ b/net/core/flow.c
@@ -35,104 +35,105 @@
atomic_t *object_ref;
};
-atomic_t flow_cache_genid = ATOMIC_INIT(0);
-
-static u32 flow_hash_shift;
-#define flow_hash_size (1 << flow_hash_shift)
-static DEFINE_PER_CPU(struct flow_cache_entry **, flow_tables) = { NULL };
-
-#define flow_table(cpu) (per_cpu(flow_tables, cpu))
-
-static struct kmem_cache *flow_cachep __read_mostly;
-
-static int flow_lwm, flow_hwm;
-
-struct flow_percpu_info {
- int hash_rnd_recalc;
- u32 hash_rnd;
- int count;
+struct flow_cache_percpu {
+ struct flow_cache_entry ** hash_table;
+ int hash_count;
+ u32 hash_rnd;
+ int hash_rnd_recalc;
+ struct tasklet_struct flush_tasklet;
};
-static DEFINE_PER_CPU(struct flow_percpu_info, flow_hash_info) = { 0 };
-
-#define flow_hash_rnd_recalc(cpu) \
- (per_cpu(flow_hash_info, cpu).hash_rnd_recalc)
-#define flow_hash_rnd(cpu) \
- (per_cpu(flow_hash_info, cpu).hash_rnd)
-#define flow_count(cpu) \
- (per_cpu(flow_hash_info, cpu).count)
-
-static struct timer_list flow_hash_rnd_timer;
-
-#define FLOW_HASH_RND_PERIOD (10 * 60 * HZ)
struct flow_flush_info {
- atomic_t cpuleft;
- struct completion completion;
+ struct flow_cache * cache;
+ atomic_t cpuleft;
+ 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))
+struct flow_cache {
+ u32 hash_shift;
+ unsigned long order;
+ struct flow_cache_percpu * percpu;
+ struct notifier_block hotcpu_notifier;
+ int low_watermark;
+ int high_watermark;
+ struct timer_list rnd_timer;
+};
+
+atomic_t flow_cache_genid = ATOMIC_INIT(0);
+static struct flow_cache flow_cache_global;
+static struct kmem_cache *flow_cachep;
+
+#define flow_cache_hash_size(cache) (1 << (cache)->hash_shift)
+#define FLOW_HASH_RND_PERIOD (10 * 60 * HZ)
static void flow_cache_new_hashrnd(unsigned long arg)
{
+ struct flow_cache *fc = (void *) arg;
int i;
for_each_possible_cpu(i)
- flow_hash_rnd_recalc(i) = 1;
+ per_cpu_ptr(fc->percpu, i)->hash_rnd_recalc = 1;
- flow_hash_rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
- add_timer(&flow_hash_rnd_timer);
+ fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
+ add_timer(&fc->rnd_timer);
}
-static void flow_entry_kill(int cpu, struct flow_cache_entry *fle)
+static void flow_entry_kill(struct flow_cache *fc,
+ struct flow_cache_percpu *fcp,
+ struct flow_cache_entry *fle)
{
if (fle->object)
atomic_dec(fle->object_ref);
kmem_cache_free(flow_cachep, fle);
- flow_count(cpu)--;
+ fcp->hash_count--;
}
-static void __flow_cache_shrink(int cpu, int shrink_to)
+static void __flow_cache_shrink(struct flow_cache *fc,
+ struct flow_cache_percpu *fcp,
+ int shrink_to)
{
struct flow_cache_entry *fle, **flp;
int i;
- for (i = 0; i < flow_hash_size; i++) {
+ for (i = 0; i < flow_cache_hash_size(fc); i++) {
int k = 0;
- flp = &flow_table(cpu)[i];
+ flp = &fcp->hash_table[i];
while ((fle = *flp) != NULL && k < shrink_to) {
k++;
flp = &fle->next;
}
while ((fle = *flp) != NULL) {
*flp = fle->next;
- flow_entry_kill(cpu, fle);
+ flow_entry_kill(fc, fcp, fle);
}
}
}
-static void flow_cache_shrink(int cpu)
+static void flow_cache_shrink(struct flow_cache *fc,
+ struct flow_cache_percpu *fcp)
{
- int shrink_to = flow_lwm / flow_hash_size;
+ int shrink_to = fc->low_watermark / flow_cache_hash_size(fc);
- __flow_cache_shrink(cpu, shrink_to);
+ __flow_cache_shrink(fc, fcp, shrink_to);
}
-static void flow_new_hash_rnd(int cpu)
+static void flow_new_hash_rnd(struct flow_cache *fc,
+ struct flow_cache_percpu *fcp)
{
- get_random_bytes(&flow_hash_rnd(cpu), sizeof(u32));
- flow_hash_rnd_recalc(cpu) = 0;
-
- __flow_cache_shrink(cpu, 0);
+ get_random_bytes(&fcp->hash_rnd, sizeof(u32));
+ fcp->hash_rnd_recalc = 0;
+ __flow_cache_shrink(fc, fcp, 0);
}
-static u32 flow_hash_code(struct flowi *key, int cpu)
+static u32 flow_hash_code(struct flow_cache *fc,
+ struct flow_cache_percpu *fcp,
+ struct flowi *key)
{
u32 *k = (u32 *) key;
- return (jhash2(k, (sizeof(*key) / sizeof(u32)), flow_hash_rnd(cpu)) &
- (flow_hash_size - 1));
+ return (jhash2(k, (sizeof(*key) / sizeof(u32)), fcp->hash_rnd)
+ & (flow_cache_hash_size(fc) - 1));
}
#if (BITS_PER_LONG == 64)
@@ -168,24 +169,25 @@
void *flow_cache_lookup(struct net *net, struct flowi *key, u16 family, u8 dir,
flow_resolve_t resolver)
{
+ struct flow_cache *fc = &flow_cache_global;
+ struct flow_cache_percpu *fcp;
struct flow_cache_entry *fle, **head;
unsigned int hash;
- int cpu;
local_bh_disable();
- cpu = smp_processor_id();
+ fcp = per_cpu_ptr(fc->percpu, smp_processor_id());
fle = NULL;
/* Packet really early in init? Making flow_cache_init a
* pre-smp initcall would solve this. --RR */
- if (!flow_table(cpu))
+ if (!fcp->hash_table)
goto nocache;
- if (flow_hash_rnd_recalc(cpu))
- flow_new_hash_rnd(cpu);
- hash = flow_hash_code(key, cpu);
+ if (fcp->hash_rnd_recalc)
+ flow_new_hash_rnd(fc, fcp);
+ hash = flow_hash_code(fc, fcp, key);
- head = &flow_table(cpu)[hash];
+ head = &fcp->hash_table[hash];
for (fle = *head; fle; fle = fle->next) {
if (fle->family == family &&
fle->dir == dir &&
@@ -204,8 +206,8 @@
}
if (!fle) {
- if (flow_count(cpu) > flow_hwm)
- flow_cache_shrink(cpu);
+ if (fcp->hash_count > fc->high_watermark)
+ flow_cache_shrink(fc, fcp);
fle = kmem_cache_alloc(flow_cachep, GFP_ATOMIC);
if (fle) {
@@ -215,7 +217,7 @@
fle->dir = dir;
memcpy(&fle->key, key, sizeof(*key));
fle->object = NULL;
- flow_count(cpu)++;
+ fcp->hash_count++;
}
}
@@ -249,14 +251,15 @@
static void flow_cache_flush_tasklet(unsigned long data)
{
struct flow_flush_info *info = (void *)data;
+ struct flow_cache *fc = info->cache;
+ struct flow_cache_percpu *fcp;
int i;
- int cpu;
- cpu = smp_processor_id();
- for (i = 0; i < flow_hash_size; i++) {
+ fcp = per_cpu_ptr(fc->percpu, smp_processor_id());
+ for (i = 0; i < flow_cache_hash_size(fc); i++) {
struct flow_cache_entry *fle;
- fle = flow_table(cpu)[i];
+ fle = fcp->hash_table[i];
for (; fle; fle = fle->next) {
unsigned genid = atomic_read(&flow_cache_genid);
@@ -272,7 +275,6 @@
complete(&info->completion);
}
-static void flow_cache_flush_per_cpu(void *) __attribute__((__unused__));
static void flow_cache_flush_per_cpu(void *data)
{
struct flow_flush_info *info = data;
@@ -280,8 +282,7 @@
struct tasklet_struct *tasklet;
cpu = smp_processor_id();
-
- tasklet = flow_flush_tasklet(cpu);
+ tasklet = &per_cpu_ptr(info->cache->percpu, cpu)->flush_tasklet;
tasklet->data = (unsigned long)info;
tasklet_schedule(tasklet);
}
@@ -294,6 +295,7 @@
/* 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());
init_completion(&info.completion);
@@ -307,62 +309,75 @@
put_online_cpus();
}
-static void __init flow_cache_cpu_prepare(int cpu)
+static void __init flow_cache_cpu_prepare(struct flow_cache *fc,
+ struct flow_cache_percpu *fcp)
{
- struct tasklet_struct *tasklet;
- unsigned long order;
+ fcp->hash_table = (struct flow_cache_entry **)
+ __get_free_pages(GFP_KERNEL|__GFP_ZERO, fc->order);
+ if (!fcp->hash_table)
+ panic("NET: failed to allocate flow cache order %lu\n", fc->order);
- for (order = 0;
- (PAGE_SIZE << order) <
- (sizeof(struct flow_cache_entry *)*flow_hash_size);
- order++)
- /* NOTHING */;
-
- flow_table(cpu) = (struct flow_cache_entry **)
- __get_free_pages(GFP_KERNEL|__GFP_ZERO, order);
- if (!flow_table(cpu))
- panic("NET: failed to allocate flow cache order %lu\n", order);
-
- flow_hash_rnd_recalc(cpu) = 1;
- flow_count(cpu) = 0;
-
- tasklet = flow_flush_tasklet(cpu);
- tasklet_init(tasklet, flow_cache_flush_tasklet, 0);
+ fcp->hash_rnd_recalc = 1;
+ fcp->hash_count = 0;
+ tasklet_init(&fcp->flush_tasklet, flow_cache_flush_tasklet, 0);
}
static int flow_cache_cpu(struct notifier_block *nfb,
unsigned long action,
void *hcpu)
{
+ struct flow_cache *fc = container_of(nfb, struct flow_cache, hotcpu_notifier);
+ int cpu = (unsigned long) hcpu;
+ struct flow_cache_percpu *fcp = per_cpu_ptr(fc->percpu, cpu);
+
if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
- __flow_cache_shrink((unsigned long)hcpu, 0);
+ __flow_cache_shrink(fc, fcp, 0);
return NOTIFY_OK;
}
-static int __init flow_cache_init(void)
+static int flow_cache_init(struct flow_cache *fc)
{
+ unsigned long order;
int i;
- flow_cachep = kmem_cache_create("flow_cache",
- sizeof(struct flow_cache_entry),
- 0, SLAB_PANIC,
- NULL);
- flow_hash_shift = 10;
- flow_lwm = 2 * flow_hash_size;
- flow_hwm = 4 * flow_hash_size;
+ fc->hash_shift = 10;
+ fc->low_watermark = 2 * flow_cache_hash_size(fc);
+ fc->high_watermark = 4 * flow_cache_hash_size(fc);
- setup_timer(&flow_hash_rnd_timer, flow_cache_new_hashrnd, 0);
- flow_hash_rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
- add_timer(&flow_hash_rnd_timer);
+ for (order = 0;
+ (PAGE_SIZE << order) <
+ (sizeof(struct flow_cache_entry *)*flow_cache_hash_size(fc));
+ order++)
+ /* NOTHING */;
+ fc->order = order;
+ fc->percpu = alloc_percpu(struct flow_cache_percpu);
+
+ setup_timer(&fc->rnd_timer, flow_cache_new_hashrnd,
+ (unsigned long) fc);
+ fc->rnd_timer.expires = jiffies + FLOW_HASH_RND_PERIOD;
+ add_timer(&fc->rnd_timer);
for_each_possible_cpu(i)
- flow_cache_cpu_prepare(i);
+ flow_cache_cpu_prepare(fc, per_cpu_ptr(fc->percpu, i));
- hotcpu_notifier(flow_cache_cpu, 0);
+ fc->hotcpu_notifier = (struct notifier_block){
+ .notifier_call = flow_cache_cpu,
+ };
+ register_hotcpu_notifier(&fc->hotcpu_notifier);
+
return 0;
}
-module_init(flow_cache_init);
+static int __init flow_cache_init_global(void)
+{
+ flow_cachep = kmem_cache_create("flow_cache",
+ sizeof(struct flow_cache_entry),
+ 0, SLAB_PANIC, NULL);
+
+ return flow_cache_init(&flow_cache_global);
+}
+
+module_init(flow_cache_init_global);
EXPORT_SYMBOL(flow_cache_genid);
EXPORT_SYMBOL(flow_cache_lookup);