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* [PATCH] net: core: fix msleep() is not accurate
@ 2020-12-10  9:35 Yejune Deng
  2020-12-10 10:19 ` Eric Dumazet
  0 siblings, 1 reply; 5+ messages in thread
From: Yejune Deng @ 2020-12-10  9:35 UTC (permalink / raw)
  To: davem, kuba, ast, andriin, daniel, edumazet, ap420073,
	bjorn.topel, xiyou.wangcong, jiri
  Cc: netdev, linux-kernel, yejune.deng

See Documentation/timers/timers-howto.rst, msleep() is not
for (1ms - 20ms), There is a more advanced API is used.

Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
---
 net/core/dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index d33099f..6e83ee03 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6726,9 +6726,9 @@ void napi_disable(struct napi_struct *n)
 	set_bit(NAPI_STATE_DISABLE, &n->state);
 
 	while (test_and_set_bit(NAPI_STATE_SCHED, &n->state))
-		msleep(1);
+		fsleep(1000);
 	while (test_and_set_bit(NAPI_STATE_NPSVC, &n->state))
-		msleep(1);
+		fsleep(1000);
 
 	hrtimer_cancel(&n->timer);
 
-- 
1.9.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread
* Re: [PATCH] net: core: fix msleep() is not accurate
  2020-12-10  9:35 [PATCH] net: core: fix msleep() is not accurate Yejune Deng
@ 2020-12-10 10:19 ` Eric Dumazet
  2020-12-11  2:43   ` Yejune Deng
  0 siblings, 1 reply; 5+ messages in thread
From: Eric Dumazet @ 2020-12-10 10:19 UTC (permalink / raw)
  To: Yejune Deng
  Cc: David Miller, Jakub Kicinski, Alexei Starovoitov,
	Andrii Nakryiko, Daniel Borkmann, Taehee Yoo,
	Björn Töpel, Cong Wang, Jiri Pirko, netdev, LKML

On Thu, Dec 10, 2020 at 10:35 AM Yejune Deng <yejune.deng@gmail.com> wrote:
>
> See Documentation/timers/timers-howto.rst, msleep() is not
> for (1ms - 20ms), There is a more advanced API is used.
>
> Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
> ---
>  net/core/dev.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index d33099f..6e83ee03 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -6726,9 +6726,9 @@ void napi_disable(struct napi_struct *n)
>         set_bit(NAPI_STATE_DISABLE, &n->state);
>
>         while (test_and_set_bit(NAPI_STATE_SCHED, &n->state))
> -               msleep(1);
> +               fsleep(1000);
>         while (test_and_set_bit(NAPI_STATE_NPSVC, &n->state))
> -               msleep(1);
> +               fsleep(1000);
>

I would prefer explicit usleep_range().

fsleep() is not common in the kernel, I had to go to its definition.

I would argue that we should  use usleep_range(10, 200)  to have an
opportunity to spend less time in napi_disable() in some cases.

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: [PATCH] net: core: fix msleep() is not accurate
  2020-12-10 10:19 ` Eric Dumazet
@ 2020-12-11  2:43   ` Yejune Deng
  0 siblings, 0 replies; 5+ messages in thread
From: Yejune Deng @ 2020-12-11  2:43 UTC (permalink / raw)
  To: Eric Dumazet
  Cc: David Miller, Jakub Kicinski, Alexei Starovoitov,
	Andrii Nakryiko, Daniel Borkmann, Taehee Yoo,
	Björn Töpel, Cong Wang, Jiri Pirko, netdev, LKML

Does anyone else have a different opinion? If not，I will adopt it and resubmit.

On Thu, Dec 10, 2020 at 6:19 PM Eric Dumazet <edumazet@google.com> wrote:
>
> On Thu, Dec 10, 2020 at 10:35 AM Yejune Deng <yejune.deng@gmail.com> wrote:
> >
> > See Documentation/timers/timers-howto.rst, msleep() is not
> > for (1ms - 20ms), There is a more advanced API is used.
> >
> > Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
> > ---
> >  net/core/dev.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/net/core/dev.c b/net/core/dev.c
> > index d33099f..6e83ee03 100644
> > --- a/net/core/dev.c
> > +++ b/net/core/dev.c
> > @@ -6726,9 +6726,9 @@ void napi_disable(struct napi_struct *n)
> >         set_bit(NAPI_STATE_DISABLE, &n->state);
> >
> >         while (test_and_set_bit(NAPI_STATE_SCHED, &n->state))
> > -               msleep(1);
> > +               fsleep(1000);
> >         while (test_and_set_bit(NAPI_STATE_NPSVC, &n->state))
> > -               msleep(1);
> > +               fsleep(1000);
> >
>
> I would prefer explicit usleep_range().
>
> fsleep() is not common in the kernel, I had to go to its definition.
>
> I would argue that we should  use usleep_range(10, 200)  to have an
> opportunity to spend less time in napi_disable() in some cases.

^ permalink raw reply	[flat|nested] 5+ messages in thread
* Re: [PATCH] net: core: fix msleep() is not accurate
  2020-12-15  2:04 Yejune Deng
@ 2020-12-16 19:33 ` Jakub Kicinski
  0 siblings, 0 replies; 5+ messages in thread
From: Jakub Kicinski @ 2020-12-16 19:33 UTC (permalink / raw)
  To: Yejune Deng
  Cc: davem, ast, andriin, jiri, edumazet, ap420073, bjorn.topel,
	netdev, linux-kernel

On Tue, 15 Dec 2020 10:04:25 +0800 Yejune Deng wrote:
> See Documentation/timers/timers-howto.rst, msleep() is not
> for (1ms - 20ms), use usleep_range() instead.
> 
> Signed-off-by: Yejune Deng <yejune.deng@gmail.com>

# Form letter - net-next is closed

We have already sent the networking pull request for 5.11 and therefore
net-next is closed for new drivers, features, code refactoring and
optimizations. We are currently accepting bug fixes only.

Please repost when net-next reopens after 5.11-rc1 is cut.

Look out for the announcement on the mailing list or check:
http://vger.kernel.org/~davem/net-next.html

RFC patches sent for review only are obviously welcome at any time.

^ permalink raw reply	[flat|nested] 5+ messages in thread
* [PATCH] net: core: fix msleep() is not accurate
@ 2020-12-15  2:04 Yejune Deng
  2020-12-16 19:33 ` Jakub Kicinski
  0 siblings, 1 reply; 5+ messages in thread
From: Yejune Deng @ 2020-12-15  2:04 UTC (permalink / raw)
  To: davem, kuba, ast, andriin, jiri, edumazet, ap420073, bjorn.topel
  Cc: netdev, linux-kernel, yejune.deng

See Documentation/timers/timers-howto.rst, msleep() is not
for (1ms - 20ms), use usleep_range() instead.

Signed-off-by: Yejune Deng <yejune.deng@gmail.com>
---
 net/core/dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index d33099f..c0aa52f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -6726,9 +6726,9 @@ void napi_disable(struct napi_struct *n)
 	set_bit(NAPI_STATE_DISABLE, &n->state);
 
 	while (test_and_set_bit(NAPI_STATE_SCHED, &n->state))
-		msleep(1);
+		usleep_range(10, 200);
 	while (test_and_set_bit(NAPI_STATE_NPSVC, &n->state))
-		msleep(1);
+		usleep_range(10, 200);
 
 	hrtimer_cancel(&n->timer);
 
-- 
1.9.1


^ permalink raw reply related	[flat|nested] 5+ messages in thread
end of thread, other threads:[~2020-12-16 19:34 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2020-12-10  9:35 [PATCH] net: core: fix msleep() is not accurate Yejune Deng
2020-12-10 10:19 ` Eric Dumazet
2020-12-11  2:43   ` Yejune Deng
2020-12-15  2:04 Yejune Deng
2020-12-16 19:33 ` Jakub Kicinski

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