Re: [Qemu-devel] [PATCH v2 3/3] slirp: set mainloop timeout with more precise value

[Jan Kiszka]

On 2013-08-14 05:02, Liu Ping Fan wrote:
> If slirp needs to emulate tcp timeout, then the timeout value
> for mainloop should be more precise, which is determined by
> slirp's fasttimo or slowtimo. Achieve this by swap the logic
> sequence of slirp_pollfds_fill and slirp_update_timeout.
> 
> Signed-off-by: Liu Ping Fan <address@hidden>
> ---
>  main-loop.c      |  3 +--
>  slirp/libslirp.h |  3 +--
>  slirp/slirp.c    | 28 ++++++++++++++++++++++++----
>  stubs/slirp.c    |  6 +-----
>  4 files changed, 27 insertions(+), 13 deletions(-)
> 
> diff --git a/main-loop.c b/main-loop.c
> index a44fff6..e258567 100644
> --- a/main-loop.c
> +++ b/main-loop.c
> @@ -458,8 +458,7 @@ int main_loop_wait(int nonblocking)
>      g_array_set_size(gpollfds, 0); /* reset for new iteration */
>      /* XXX: separate device handlers from system ones */
>  #ifdef CONFIG_SLIRP
> -    slirp_update_timeout(&timeout);
> -    slirp_pollfds_fill(gpollfds);
> +    slirp_pollfds_fill(gpollfds, &timeout);
>  #endif
>      qemu_iohandler_fill(gpollfds);
>      ret = os_host_main_loop_wait(timeout);
> diff --git a/slirp/libslirp.h b/slirp/libslirp.h
> index ceabff8..5bdcbd5 100644
> --- a/slirp/libslirp.h
> +++ b/slirp/libslirp.h
> @@ -16,8 +16,7 @@ Slirp *slirp_init(int restricted, struct in_addr vnetwork,
>                    void *opaque);
>  void slirp_cleanup(Slirp *slirp);
>  
> -void slirp_update_timeout(uint32_t *timeout);
> -void slirp_pollfds_fill(GArray *pollfds);
> +void slirp_pollfds_fill(GArray *pollfds, uint32_t *timeout);
>  
>  void slirp_pollfds_poll(GArray *pollfds, int select_error);
>  
> diff --git a/slirp/slirp.c b/slirp/slirp.c
> index c224523..da759a7 100644
> --- a/slirp/slirp.c
> +++ b/slirp/slirp.c
> @@ -260,18 +260,37 @@ void slirp_cleanup(Slirp *slirp)
>  #define CONN_CANFSEND(so) (((so)->so_state & 
> (SS_FCANTSENDMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
>  #define CONN_CANFRCV(so) (((so)->so_state & 
> (SS_FCANTRCVMORE|SS_ISFCONNECTED)) == SS_ISFCONNECTED)
>  
> -void slirp_update_timeout(uint32_t *timeout)
> +static void slirp_update_timeout(uint32_t *timeout)
>  {
> -    if (!QTAILQ_EMPTY(&slirp_instances)) {
> -        *timeout = MIN(1000, *timeout);
> +    Slirp *slirp;
> +    uint32_t t;
> +
> +    if (*timeout <= TIMEOUT_FAST) {
> +        return;
> +    }
> +    t = *timeout;
> +
> +    /* If we have tcp timeout with slirp, then we will fill @timeout with
> +     * more precise value.
> +     */
> +    QTAILQ_FOREACH(slirp, &slirp_instances, entry) {
> +        if (slirp->time_fasttimo) {
> +            *timeout = TIMEOUT_FAST;
> +            return;
> +        }
> +        if (slirp->do_slowtimo) {
> +            t = MIN(TIMEOUT_SLOW, t);
> +        }
>      }
> +    *timeout = t;
>  }
>  
> -void slirp_pollfds_fill(GArray *pollfds)
> +void slirp_pollfds_fill(GArray *pollfds, uint32_t *timeout)
>  {
>      Slirp *slirp;
>      struct socket *so, *so_next;
>  
> +    *timeout = MIN(1000, *timeout);

This should come after the QTAILQ_EMPTY check: no slirps, no timeout
modifications.

>      if (QTAILQ_EMPTY(&slirp_instances)) {
>          return;
>      }
> @@ -437,6 +456,7 @@ void slirp_pollfds_fill(GArray *pollfds)
>              }
>          }
>      }
> +    slirp_update_timeout(timeout);
>  }
>  
>  void slirp_pollfds_poll(GArray *pollfds, int select_error)
> diff --git a/stubs/slirp.c b/stubs/slirp.c
> index f1fc833..bd0ac7f 100644
> --- a/stubs/slirp.c
> +++ b/stubs/slirp.c
> @@ -1,11 +1,7 @@
>  #include "qemu-common.h"
>  #include "slirp/slirp.h"
>  
> -void slirp_update_timeout(uint32_t *timeout)
> -{
> -}
> -
> -void slirp_pollfds_fill(GArray *pollfds)
> +void slirp_pollfds_fill(GArray *pollfds, uint32_t *timeout)
>  {
>  }
>  
> 

The rest looks good!

Jan

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