[Xcb] [Xcb-commit] 2 commits - src

[Jeremy A. Kolb]

This sounds kind of important.  When is the next release planned for?

On Sun, 28 Oct 2007, Jamey Sharp wrote:

> src/xcb_conn.c |   33 +++++++++++++++++++++++++++++++--
> src/xcb_out.c  |    4 ++--
> src/xcbint.h   |    1 +
> 3 files changed, 34 insertions(+), 4 deletions(-)
>
> New commits:
> commit a29fbc2645fabb96d02c382ffef499b48fb1514a
> Author: Jamey Sharp <jamey at minilop.net>
> Date:   Sun Oct 28 13:28:18 2007 -0700
>
>    Don't hold the xlib-xcb lock while sleeping: that allows deadlock.
>
>    With this patch, `ico -threads 2` runs without deadlock.
>
>    Many thanks to Christoph Pfister <christophpfister at gmail.com> for
>    pointing out the problem, providing detailed analyses, explaining it to
>    me repeatedly until I understood what was going on, and proposing and
>    reviewing possible solutions.
>
>    Signed-off-by: Jamey Sharp <jamey at minilop.net>
>    Acked-by: Christoph Pfister <christophpfister at gmail.com>
>
> diff --git a/src/xcb_conn.c b/src/xcb_conn.c
> index 9a58bff..e7856c3 100644
> --- a/src/xcb_conn.c
> +++ b/src/xcb_conn.c
> @@ -290,12 +290,25 @@ void _xcb_unlock_io(xcb_connection_t *c)
>
> void _xcb_wait_io(xcb_connection_t *c, pthread_cond_t *cond)
> {
> +    int xlib_locked = c->xlib.lock;
> +    if(xlib_locked)
> +    {
> +        c->xlib.lock = 0;
> +        pthread_cond_broadcast(&c->xlib.cond);
> +    }
>     pthread_cond_wait(cond, &c->iolock);
> +    if(xlib_locked)
> +    {
> +        while(c->xlib.lock)
> +            pthread_cond_wait(&c->xlib.cond, &c->iolock);
> +        c->xlib.lock = 1;
> +        c->xlib.thread = pthread_self();
> +    }
> }
>
> int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vector, int *count)
> {
> -    int ret;
> +    int ret, xlib_locked;
>     fd_set rfds, wfds;
>
>     /* If the thing I should be doing is already being done, wait for it. */
> @@ -316,6 +329,12 @@ int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vec
>         ++c->out.writing;
>     }
>
> +    xlib_locked = c->xlib.lock;
> +    if(xlib_locked)
> +    {
> +        c->xlib.lock = 0;
> +        pthread_cond_broadcast(&c->xlib.cond);
> +    }
>     _xcb_unlock_io(c);
>     do {
> 	ret = select(c->fd + 1, &rfds, &wfds, 0, 0);
> @@ -326,6 +345,11 @@ int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vec
> 	ret = 0;
>     }
>     _xcb_lock_io(c);
> +    if(xlib_locked)
> +    {
> +        c->xlib.lock = 1;
> +        c->xlib.thread = pthread_self();
> +    }
>
>     if(ret)
>     {
> commit f6b75d6090dc40918196d2b902e9616d0199af42
> Author: Jamey Sharp <jamey at minilop.net>
> Date:   Sun Oct 28 11:56:08 2007 -0700
>
>    Factor pthread_cond_wait(iolock) to _xcb_wait_io.
>
>    This parallels the _xcb_lock_io and _xcb_unlock_io factoring.
>
> diff --git a/src/xcb_conn.c b/src/xcb_conn.c
> index 827a12b..9a58bff 100644
> --- a/src/xcb_conn.c
> +++ b/src/xcb_conn.c
> @@ -288,6 +288,11 @@ void _xcb_unlock_io(xcb_connection_t *c)
>     pthread_mutex_unlock(&c->iolock);
> }
>
> +void _xcb_wait_io(xcb_connection_t *c, pthread_cond_t *cond)
> +{
> +    pthread_cond_wait(cond, &c->iolock);
> +}
> +
> int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vector, int *count)
> {
>     int ret;
> @@ -296,7 +301,7 @@ int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vec
>     /* If the thing I should be doing is already being done, wait for it. */
>     if(count ? c->out.writing : c->in.reading)
>     {
> -        pthread_cond_wait(cond, &c->iolock);
> +        _xcb_wait_io(c, cond);
>         return 1;
>     }
>
> diff --git a/src/xcb_out.c b/src/xcb_out.c
> index caf8ef5..60226e5 100644
> --- a/src/xcb_out.c
> +++ b/src/xcb_out.c
> @@ -190,7 +190,7 @@ unsigned int xcb_send_request(xcb_connection_t *c, int flags, struct iovec *vect
>     _xcb_lock_io(c);
>     /* wait for other writing threads to get out of my way. */
>     while(c->out.writing)
> -        pthread_cond_wait(&c->out.cond, &c->iolock);
> +        _xcb_wait_io(c, &c->out.cond);
>
>     request = ++c->out.request;
>     /* send GetInputFocus (sync) when 64k-2 requests have been sent without
> @@ -297,7 +297,7 @@ int _xcb_out_flush_to(xcb_connection_t *c, unsigned int request)
>         return _xcb_out_send(c, &vec_ptr, &count);
>     }
>     while(c->out.writing)
> -        pthread_cond_wait(&c->out.cond, &c->iolock);
> +        _xcb_wait_io(c, &c->out.cond);
>     assert(XCB_SEQUENCE_COMPARE(c->out.request_written, >=, request));
>     return 1;
> }
> diff --git a/src/xcbint.h b/src/xcbint.h
> index ab692ee..ab0264f 100644
> --- a/src/xcbint.h
> +++ b/src/xcbint.h
> @@ -183,6 +183,7 @@ struct xcb_connection_t {
> };
>
> void _xcb_conn_shutdown(xcb_connection_t *c);
> +void _xcb_wait_io(xcb_connection_t *c, pthread_cond_t *cond);
> int _xcb_conn_wait(xcb_connection_t *c, pthread_cond_t *cond, struct iovec **vector, int *count);
>
>
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