[PATCH V3 4/7] PHYLIB: queue work on any cpu

From: Viresh Kumar
Date: Mon Mar 18 2013 - 11:24:43 EST

Phylib uses workqueues for multiple purposes. There is no real dependency of
scheduling these on the cpu which scheduled them.

On a idle system, it is observed that and idle cpu wakes up many times just to
service this work. It would be better if we can schedule it on a cpu which isn't
idle to save on power.

By idle cpu (from scheduler's perspective) we mean:
- Current task is idle task
- nr_running == 0
- wake_list is empty

This patch replaces the schedule_work() and schedule_delayed_work() routines
with their queue_[delayed_]work_on_any_cpu() siblings with system_wq as

These routines would look for the closest (via scheduling domains) non-idle cpu
(non-idle from schedulers perspective). If the current cpu is not idle or all
cpus are idle, work will be scheduled on local cpu.

Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
drivers/net/phy/phy.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index 298b4c2..a517706 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -439,7 +439,7 @@ void phy_start_machine(struct phy_device *phydev,
phydev->adjust_state = handler;

- schedule_delayed_work(&phydev->state_queue, HZ);
+ queue_delayed_work_on_any_cpu(system_wq, &phydev->state_queue, HZ);

@@ -527,7 +527,7 @@ static irqreturn_t phy_interrupt(int irq, void *phy_dat)

- schedule_work(&phydev->phy_queue);
+ queue_work_on_any_cpu(system_wq, &phydev->phy_queue);

@@ -682,7 +682,7 @@ static void phy_change(struct work_struct *work)

/* reschedule state queue work to run as soon as possible */
- schedule_delayed_work(&phydev->state_queue, 0);
+ queue_delayed_work_on_any_cpu(system_wq, &phydev->state_queue, 0);


@@ -966,7 +966,8 @@ void phy_state_machine(struct work_struct *work)
if (err < 0)

- schedule_delayed_work(&phydev->state_queue, PHY_STATE_TIME * HZ);
+ queue_delayed_work_on_any_cpu(system_wq, &phydev->state_queue,

static inline void mmd_phy_indirect(struct mii_bus *bus, int prtad, int devad,

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