Re: [PATCH] net: core: fix msleep() is not accurate

[Eric Dumazet <edumazet@google.com>]

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.