Re: 答复: [PATCH] sunrpc: queue work on system_power_efficient_wq

Resend behalf on Ke Wang.

Thanks,
Chunyan

On 20 September 2016 at 10:33, Ke Wang (王科) [off-list ref] wrote:

May I have any comments for this patch?
or
This patch can be merged directly into next release?

Thanks,
Ke
________________________________________
发件人: Anna Schumaker [off-list ref]
发送时间: 2016年9月2日 2:46
收件人: Chunyan Zhang; trond.myklebust@primarydata.com; anna.schumaker-HgOvQuBEEgTQT0dZR+AlfA@public.gmane.org; davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org
抄送: linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org; Ke Wang (王科)
主题: Re: [PATCH] sunrpc: queue work on system_power_efficient_wq

On 09/01/2016 03:30 AM, Chunyan Zhang wrote:

quoted

From: Ke Wang <redacted>

sunrpc uses workqueue to clean cache regulary. There is no real dependency
of executing work on the cpu which queueing it.

On a idle system, especially for a heterogeneous systems like big.LITTLE,
it is observed that the big idle cpu was woke up many times just to service
this work, which against the principle of power saving. It would be better
if we can schedule it on a cpu which the scheduler believes to be the most
appropriate one.

After apply this patch, system_wq will be replaced by
system_power_efficient_wq for sunrpc. This functionality is enabled when
CONFIG_WQ_POWER_EFFICIENT is selected.

Makes sense to me, but I'm a little surprised that there isn't a "schedule_delayed_power_efficient_work()" function to match how the normal workqueue is used.

Thanks,
Anna

quoted

Signed-off-by: Ke Wang <redacted>
---
 net/sunrpc/cache.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 4d8e11f..8aabe12 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c

@@ -353,7 +353,7 @@ void sunrpc_init_cache_detail(struct cache_detail *cd)
      spin_unlock(&cache_list_lock);

      /* start the cleaning process */
-     schedule_delayed_work(&cache_cleaner, 0);
+     queue_delayed_work(system_power_efficient_wq, &cache_cleaner, 0);
 }
 EXPORT_SYMBOL_GPL(sunrpc_init_cache_detail);

@@ -476,7 +476,8 @@ static void do_cache_clean(struct work_struct *work)
              delay = 0;

      if (delay)
-             schedule_delayed_work(&cache_cleaner, delay);
+             queue_delayed_work(system_power_efficient_wq,
+                                &cache_cleaner, delay);
 }

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