This patch adds a rhastable for mac address lookup of hwsim radios. This
especially improve the speed on reception of a netlink message with a new
frame. Although redundant, we keep holding a normal list for all radios,
since the rhashtable_walk interface adds a lot of overhead for iterating
over all radios and the doc of rhashtable recommend a redundant structure
for stable walks in such situations.
Since rhashtable is rcu protected we do not need a lock for delivering
frames and thus improving this scenario.
Signed-off-by: Benjamin Beichler <[email protected]>
---
drivers/net/wireless/mac80211_hwsim.c | 57 +++++++++++++++++++++++++----------
1 file changed, 41 insertions(+), 16 deletions(-)
diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 742a1551bb1c..55d25e3fbbcc 100644
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -32,6 +32,7 @@
#include <net/genetlink.h>
#include <net/net_namespace.h>
#include <net/netns/generic.h>
+#include <linux/rhashtable.h>
#include "mac80211_hwsim.h"
#define WARN_QUEUE 100
@@ -490,6 +491,7 @@ static const struct ieee80211_iface_combination hwsim_if_comb_p2p_dev[] = {
static spinlock_t hwsim_radio_lock;
static LIST_HEAD(hwsim_radios);
static struct workqueue_struct *hwsim_wq;
+static struct rhashtable hwsim_radios_rht;
static int hwsim_radio_idx;
static struct platform_driver mac80211_hwsim_driver = {
@@ -500,6 +502,7 @@ static struct platform_driver mac80211_hwsim_driver = {
struct mac80211_hwsim_data {
struct list_head list;
+ struct rhash_head rht;
struct ieee80211_hw *hw;
struct device *dev;
struct ieee80211_supported_band bands[NUM_NL80211_BANDS];
@@ -574,6 +577,20 @@ struct mac80211_hwsim_data {
u64 tx_failed;
};
+static u32 hwsim_table_hash(const void *addr, u32 len, u32 seed)
+{
+ /* Use last four bytes of hw addr as hash index */
+ return jhash_1word(*(u32 *)(addr + 2), seed);
+}
+
+static const struct rhashtable_params hwsim_rht_params = {
+ .nelem_hint = 2,
+ .automatic_shrinking = true,
+ .key_len = ETH_ALEN,
+ .key_offset = offsetof(struct mac80211_hwsim_data, addresses[1]),
+ .head_offset = offsetof(struct mac80211_hwsim_data, rht),
+ .hashfn = hwsim_table_hash,
+};
struct hwsim_radiotap_hdr {
struct ieee80211_radiotap_header hdr;
@@ -2731,6 +2748,15 @@ static int mac80211_hwsim_new_radio(struct genl_info *info,
CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
spin_lock_bh(&hwsim_radio_lock);
+ err = rhashtable_insert_fast(&hwsim_radios_rht, &data->rht,
+ hwsim_rht_params);
+ if (err < 0) {
+ pr_debug("mac80211_hwsim: radio index %d already present\n",
+ idx);
+ spin_unlock_bh(&hwsim_radio_lock);
+ goto failed_final_insert;
+ }
+
list_add_tail(&data->list, &hwsim_radios);
spin_unlock_bh(&hwsim_radio_lock);
@@ -2739,6 +2765,9 @@ static int mac80211_hwsim_new_radio(struct genl_info *info,
return idx;
+failed_final_insert:
+ debugfs_remove_recursive(data->debugfs);
+ ieee80211_unregister_hw(data->hw);
failed_hw:
device_release_driver(data->dev);
failed_bind:
@@ -2874,22 +2903,9 @@ static void hwsim_mon_setup(struct net_device *dev)
static struct mac80211_hwsim_data *get_hwsim_data_ref_from_addr(const u8 *addr)
{
- struct mac80211_hwsim_data *data;
- bool _found = false;
-
- spin_lock_bh(&hwsim_radio_lock);
- list_for_each_entry(data, &hwsim_radios, list) {
- if (memcmp(data->addresses[1].addr, addr, ETH_ALEN) == 0) {
- _found = true;
- break;
- }
- }
- spin_unlock_bh(&hwsim_radio_lock);
-
- if (!_found)
- return NULL;
-
- return data;
+ return rhashtable_lookup_fast(&hwsim_radios_rht,
+ addr,
+ hwsim_rht_params);
}
static void hwsim_register_wmediumd(struct net *net, u32 portid)
@@ -3191,6 +3207,8 @@ static int hwsim_del_radio_nl(struct sk_buff *msg, struct genl_info *info)
continue;
list_del(&data->list);
+ rhashtable_remove_fast(&hwsim_radios_rht, &data->rht,
+ hwsim_rht_params);
spin_unlock_bh(&hwsim_radio_lock);
mac80211_hwsim_del_radio(data, wiphy_name(data->hw->wiphy),
info);
@@ -3346,6 +3364,8 @@ static void remove_user_radios(u32 portid)
list_for_each_entry_safe(entry, tmp, &hwsim_radios, list) {
if (entry->destroy_on_close && entry->portid == portid) {
list_del(&entry->list);
+ rhashtable_remove_fast(&hwsim_radios_rht, &entry->rht,
+ hwsim_rht_params);
INIT_WORK(&entry->destroy_work, destroy_radio);
queue_work(hwsim_wq, &entry->destroy_work);
}
@@ -3421,6 +3441,8 @@ static void __net_exit hwsim_exit_net(struct net *net)
continue;
list_del(&data->list);
+ rhashtable_remove_fast(&hwsim_radios_rht, &data->rht,
+ hwsim_rht_params);
INIT_WORK(&data->destroy_work, destroy_radio);
queue_work(hwsim_wq, &data->destroy_work);
}
@@ -3458,6 +3480,8 @@ static int __init init_mac80211_hwsim(void)
if (!hwsim_wq)
return -ENOMEM;
+ rhashtable_init(&hwsim_radios_rht, &hwsim_rht_params);
+
err = register_pernet_device(&hwsim_net_ops);
if (err)
return err;
@@ -3598,6 +3622,7 @@ static void __exit exit_mac80211_hwsim(void)
mac80211_hwsim_free();
flush_workqueue(hwsim_wq);
+ rhashtable_destroy(&hwsim_radios_rht);
unregister_netdev(hwsim_mon);
platform_driver_unregister(&mac80211_hwsim_driver);
unregister_pernet_device(&hwsim_net_ops);
--
2.15.1
On Wed, 2018-01-10 at 17:42 +0100, Benjamin Beichler wrote:
> This patch adds a rhastable for mac address lookup of hwsim radios. This
> especially improve the speed on reception of a netlink message with a new
> frame. Although redundant, we keep holding a normal list for all radios,
> since the rhashtable_walk interface adds a lot of overhead for iterating
> over all radios and the doc of rhashtable recommend a redundant structure
> for stable walks in such situations.
>
> Since rhashtable is rcu protected we do not need a lock for delivering
> frames and thus improving this scenario.
Applied, but
> +static u32 hwsim_table_hash(const void *addr, u32 len, u32 seed)
> +{
> + /* Use last four bytes of hw addr as hash index */
> + return jhash_1word(*(u32 *)(addr + 2), seed);
> +}
I removed this, because that isn't actually safe - there's only 2-byte
alignment guaranteed... rhashtable will just do jhash() on the whole
thing, which should be fast enough.
johannes