[PATCH 1/2] net/ipv4: queue work on power efficient wq

From: Viresh Kumar
Date: Wed Jan 22 2014 - 01:54:38 EST

Workqueue used in ipv4 layer have no real dependency of scheduling these on the
cpu which scheduled them.

On a idle system, it is observed that an idle cpu wakes up many times just to
service this work. It would be better if we can schedule it on a cpu which the
scheduler believes to be the most appropriate one.

This patch replaces normal workqueues with power efficient versions. This
doesn't change existing behavior of code unless CONFIG_WQ_POWER_EFFICIENT is

Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Initial support for power-efficient workqueues was added here:

net/ipv4/devinet.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 646023b..ac2dff3 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -474,7 +474,7 @@ static int __inet_insert_ifa(struct in_ifaddr *ifa, struct nlmsghdr *nlh,
inet_hash_insert(dev_net(in_dev->dev), ifa);

- schedule_delayed_work(&check_lifetime_work, 0);
+ queue_delayed_work(system_power_efficient_wq, &check_lifetime_work, 0);

/* Send message first, then call notifier.
Notifier will trigger FIB update, so that
@@ -684,7 +684,8 @@ static void check_lifetime(struct work_struct *work)
if (time_before(next_sched, now + ADDRCONF_TIMER_FUZZ_MAX))
next_sched = now + ADDRCONF_TIMER_FUZZ_MAX;

- schedule_delayed_work(&check_lifetime_work, next_sched - now);
+ queue_delayed_work(system_power_efficient_wq, &check_lifetime_work,
+ next_sched - now);

static void set_ifa_lifetime(struct in_ifaddr *ifa, __u32 valid_lft,
@@ -842,7 +843,8 @@ static int inet_rtm_newaddr(struct sk_buff *skb, struct nlmsghdr *nlh)
ifa = ifa_existing;
set_ifa_lifetime(ifa, valid_lft, prefered_lft);
- schedule_delayed_work(&check_lifetime_work, 0);
+ queue_delayed_work(system_power_efficient_wq,
+ &check_lifetime_work, 0);
rtmsg_ifa(RTM_NEWADDR, ifa, nlh, NETLINK_CB(skb).portid);
blocking_notifier_call_chain(&inetaddr_chain, NETDEV_UP, ifa);
@@ -2322,7 +2324,7 @@ void __init devinet_init(void)
register_gifconf(PF_INET, inet_gifconf);

- schedule_delayed_work(&check_lifetime_work, 0);
+ queue_delayed_work(system_power_efficient_wq, &check_lifetime_work, 0);



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