Re: [Qemu-devel] [PATCH 11/20] qemu-char: use a glib timeout instead of qemu-timer

[Anthony Liguori <aliguori@us.ibm.com>]

Laurent Desnogues <laurent.desnogues@gmail.com> writes:

> Hello,
>
> On Tue, Mar 5, 2013 at 6:51 PM, Amit Shah <amit.shah@redhat.com> wrote:
>> From: Anthony Liguori <aliguori@us.ibm.com>
>>
>> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
>> Signed-off-by: Amit Shah <amit.shah@redhat.com>
>> ---
>>  qemu-char.c | 68 ++++++++++++++++++++++++++++++++++++++++---------------------
>>  1 file changed, 45 insertions(+), 23 deletions(-)
>>
>> diff --git a/qemu-char.c b/qemu-char.c
>> index eb0ac81..6dba943 100644
>> --- a/qemu-char.c
>> +++ b/qemu-char.c
>> @@ -990,12 +990,50 @@ typedef struct {
>>      int connected;
>>      int polling;
>>      int read_bytes;
>> -    QEMUTimer *timer;
>> +    guint timer_tag;
>>  } PtyCharDriver;
>>
>>  static void pty_chr_update_read_handler(CharDriverState *chr);
>>  static void pty_chr_state(CharDriverState *chr, int connected);
>>
>> +static gboolean pty_chr_timer(gpointer opaque)
>> +{
>> +    struct CharDriverState *chr = opaque;
>> +    PtyCharDriver *s = chr->opaque;
>> +
>> +    if (s->connected) {
>> +        goto out;
>> +    }
>> +    if (s->polling) {
>> +        /* If we arrive here without polling being cleared due
>> +         * read returning -EIO, then we are (re-)connected */
>> +        pty_chr_state(chr, 1);
>> +        goto out;
>> +    }
>> +
>> +    /* Next poll ... */
>> +    pty_chr_update_read_handler(chr);
>> +
>> +out:
>> +    return FALSE;
>> +}
>> +
>> +static void pty_chr_rearm_timer(CharDriverState *chr, int ms)
>> +{
>> +    PtyCharDriver *s = chr->opaque;
>> +
>> +    if (s->timer_tag) {
>> +        g_source_remove(s->timer_tag);
>> +        s->timer_tag = 0;
>> +    }
>> +
>> +    if (ms == 1000) {
>> +        s->timer_tag = g_timeout_add_seconds(1, pty_chr_timer, chr);
>
> It looks like g_timeout_add_seconds isn't available for
> poor people using some old distros (glib 2.12.3 here).

Can you test adding:

#if !GLIB_CHECK_VERSION(2, 14, 0)
static guint g_timeout_add_seconds(guint interval, GSourceFunc function,
                                   gpointer data)
{
    return g_timeout_add(interval * 1000, function, data);
}
#endif

We probably should introduce a glib-compat to centralize work arounds
for older versions of glib...

Regards,

Anthony Liguori

>
> Thanks,
>
> Laurent
>
>> +    } else {
>> +        s->timer_tag = g_timeout_add(ms, pty_chr_timer, chr);
>> +    }
>> +}
>> +
>>  static int pty_chr_write(CharDriverState *chr, const uint8_t *buf, int len)
>>  {
>>      PtyCharDriver *s = chr->opaque;
>> @@ -1065,7 +1103,7 @@ static void pty_chr_update_read_handler(CharDriverState *chr)
>>       * timeout to the normal (much longer) poll interval before the
>>       * timer triggers.
>>       */
>> -    qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 10);
>> +    pty_chr_rearm_timer(chr, 10);
>>  }
>>
>>  static void pty_chr_state(CharDriverState *chr, int connected)
>> @@ -1080,7 +1118,7 @@ static void pty_chr_state(CharDriverState *chr, int connected)
>>          /* (re-)connect poll interval for idle guests: once per second.
>>           * We check more frequently in case the guests sends data to
>>           * the virtual device linked to our pty. */
>> -        qemu_mod_timer(s->timer, qemu_get_clock_ms(rt_clock) + 1000);
>> +        pty_chr_rearm_timer(chr, 1000);
>>      } else {
>>          if (!s->connected)
>>              qemu_chr_generic_open(chr);
>> @@ -1088,23 +1126,6 @@ static void pty_chr_state(CharDriverState *chr, int connected)
>>      }
>>  }
>>
>> -static void pty_chr_timer(void *opaque)
>> -{
>> -    struct CharDriverState *chr = opaque;
>> -    PtyCharDriver *s = chr->opaque;
>> -
>> -    if (s->connected)
>> -        return;
>> -    if (s->polling) {
>> -        /* If we arrive here without polling being cleared due
>> -         * read returning -EIO, then we are (re-)connected */
>> -        pty_chr_state(chr, 1);
>> -        return;
>> -    }
>> -
>> -    /* Next poll ... */
>> -    pty_chr_update_read_handler(chr);
>> -}
>>
>>  static void pty_chr_close(struct CharDriverState *chr)
>>  {
>> @@ -1117,8 +1138,9 @@ static void pty_chr_close(struct CharDriverState *chr)
>>      fd = g_io_channel_unix_get_fd(s->fd);
>>      g_io_channel_unref(s->fd);
>>      close(fd);
>> -    qemu_del_timer(s->timer);
>> -    qemu_free_timer(s->timer);
>> +    if (s->timer_tag) {
>> +        g_source_remove(s->timer_tag);
>> +    }
>>      g_free(s);
>>      qemu_chr_be_event(chr, CHR_EVENT_CLOSED);
>>  }
>> @@ -1170,7 +1192,7 @@ static CharDriverState *qemu_chr_open_pty(QemuOpts *opts)
>>      chr->chr_add_watch = pty_chr_add_watch;
>>
>>      s->fd = io_channel_from_fd(master_fd);
>> -    s->timer = qemu_new_timer_ms(rt_clock, pty_chr_timer, chr);
>> +    s->timer_tag = 0;
>>
>>      return chr;
>>  }
>> --
>> 1.8.1.2
>>
>>