[dpdk-dev] [PATCH] vhost: allow for many vhost user ports
Yuanhan Liu
yuanhan.liu at linux.intel.com
Tue Dec 6 07:56:33 CET 2016
On Thu, Dec 01, 2016 at 04:26:50PM +0100, Jan Wickbom wrote:
> Currently select() is used to monitor file descriptors for vhostuser
> ports. This limits the number of ports possible to create since the
> fd number is used as index in the fd_set and we have seen fds > 1023.
Yeah, it's a known issue for a while. Thanks for making a patch to fix
that!
> This patch changes select() to poll(). This way we can keep an
> packed (pollfd) array for the fds, e.g. as many fds as the size of
> the array.
>
> Also see:
> http://dpdk.org/ml/archives/dev/2016-April/037024.html
>
...
> +/**
> + * Adjusts the highest index populated in the array of fds
This function only shrinks (but not extends) the fdset array, so why
not naming it to something like "fdset_shrink".
> + * @return
> + * Index of highest position populated + 1.
I think it's clearer to say "The new size of fdset".
> @@ -189,7 +206,7 @@
> pfdset->fd[i].fd = -1;
> pfdset->fd[i].rcb = pfdset->fd[i].wcb = NULL;
> pfdset->fd[i].dat = NULL;
> - pfdset->num--;
> + (void) fdset_adjust_num(pfdset);
Unncessary cast.
> i = -1;
> }
> pthread_mutex_unlock(&pfdset->fd_mutex);
> @@ -211,12 +228,12 @@
>
> pfdset->fd[index].fd = -1;
> pfdset->fd[index].rcb = pfdset->fd[index].wcb = NULL;
> - pfdset->fd[index].dat = NULL;
> - pfdset->num--;
> + (void) fdset_adjust_num(pfdset);
>
> pthread_mutex_unlock(&pfdset->fd_mutex);
> }
>
> +
> /**
> * This functions runs in infinite blocking loop until there is no fd in
> * pfdset. It calls corresponding r/w handler if there is event on the fd.
> @@ -229,44 +246,48 @@
> void
> fdset_event_dispatch(struct fdset *pfdset)
> {
> - fd_set rfds, wfds;
> - int i, maxfds;
> + int i;
> struct fdentry *pfdentry;
> - int num = MAX_FDS;
> + int numfds;
> fd_cb rcb, wcb;
> void *dat;
> int fd;
> int remove1, remove2;
> int ret;
> + int handled;
>
> if (pfdset == NULL)
> return;
>
> + struct pollfd * const rwfds =
> + rte_malloc("struct pollfd", MAX_FDS * sizeof(*rwfds), 0);
There is neither a NULL check, nor a free after the usage. Since it's
a fixed size at compile time (MAX_FDS), you might want to define a
static array for that.
--yliu
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