[RFC PATCH] net: core: move core networking work to power efficient workqueue

From: Zoran Markovic
Date: Thu Jan 30 2014 - 19:33:50 EST


From: Shaibal Dutta <shaibal.dutta@xxxxxxxxxxxx>

This patch moves the following work to the power efficient workqueue:
- Transmit work of netpoll
- Destination cache garbage collector work
- Link watch event handler work

In general, assignment of CPUs to pending work could be deferred to
the scheduler in order to extend idle residency time and improve
power efficiency. I would value community's opinion on the migration
of this work to the power efficient workqueue, with an emphasis on
migration of netpoll's transmit work.

This functionality is enabled when CONFIG_WQ_POWER_EFFICIENT is selected.

Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Jiri Pirko <jiri@xxxxxxxxxxx>
Cc: YOSHIFUJI Hideaki <yoshfuji@xxxxxxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Julian Anastasov <ja@xxxxxx>
Cc: Flavio Leitner <fbl@xxxxxxxxxx>
Cc: Neil Horman <nhorman@xxxxxxxxxxxxx>
Cc: Patrick McHardy <kaber@xxxxxxxxx>
Cc: John Fastabend <john.r.fastabend@xxxxxxxxx>
Cc: Amerigo Wang <amwang@xxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Jason Wang <jasowang@xxxxxxxxxx>
Cc: Antonio Quartulli <antonio@xxxxxxxxxxxxxx>
Cc: Simon Horman <horms@xxxxxxxxxxxx>
Cc: Nikolay Aleksandrov <nikolay@xxxxxxxxxx>
Signed-off-by: Shaibal Dutta <shaibal.dutta@xxxxxxxxxxxx>
[zoran.markovic@xxxxxxxxxx: Rebased to latest kernel version. Edited
calls to mod_delayed_work to reference power efficient workqueue.
Added commit message.]
Signed-off-by: Zoran Markovic <zoran.markovic@xxxxxxxxxx>
---
net/core/dst.c | 5 +++--
net/core/link_watch.c | 5 +++--
net/core/netpoll.c | 6 ++++--
3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/net/core/dst.c b/net/core/dst.c
index ca4231e..cc28352 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -135,7 +135,8 @@ loop:
*/
if (expires > 4*HZ)
expires = round_jiffies_relative(expires);
- schedule_delayed_work(&dst_gc_work, expires);
+ queue_delayed_work(system_power_efficient_wq,
+ &dst_gc_work, expires);
}

spin_unlock_bh(&dst_garbage.lock);
@@ -223,7 +224,7 @@ void __dst_free(struct dst_entry *dst)
if (dst_garbage.timer_inc > DST_GC_INC) {
dst_garbage.timer_inc = DST_GC_INC;
dst_garbage.timer_expires = DST_GC_MIN;
- mod_delayed_work(system_wq, &dst_gc_work,
+ mod_delayed_work(system_power_efficient_wq, &dst_gc_work,
dst_garbage.timer_expires);
}
spin_unlock_bh(&dst_garbage.lock);
diff --git a/net/core/link_watch.c b/net/core/link_watch.c
index 9c3a839..0ae3994 100644
--- a/net/core/link_watch.c
+++ b/net/core/link_watch.c
@@ -135,9 +135,10 @@ static void linkwatch_schedule_work(int urgent)
* override the existing timer.
*/
if (test_bit(LW_URGENT, &linkwatch_flags))
- mod_delayed_work(system_wq, &linkwatch_work, 0);
+ mod_delayed_work(system_power_efficient_wq, &linkwatch_work, 0);
else
- schedule_delayed_work(&linkwatch_work, delay);
+ queue_delayed_work(system_power_efficient_wq,
+ &linkwatch_work, delay);
}


diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index c03f3de..2c8f839 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -101,7 +101,8 @@ static void queue_process(struct work_struct *work)
__netif_tx_unlock(txq);
local_irq_restore(flags);

- schedule_delayed_work(&npinfo->tx_work, HZ/10);
+ queue_delayed_work(system_power_efficient_wq,
+ &npinfo->tx_work, HZ/10);
return;
}
__netif_tx_unlock(txq);
@@ -423,7 +424,8 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,

if (status != NETDEV_TX_OK) {
skb_queue_tail(&npinfo->txq, skb);
- schedule_delayed_work(&npinfo->tx_work,0);
+ queue_delayed_work(system_power_efficient_wq,
+ &npinfo->tx_work, 0);
}
}
EXPORT_SYMBOL(netpoll_send_skb_on_dev);
--
1.7.9.5

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