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Re: [Qemu-devel] [PATCH v2] chardev: Use timer instead of bottom-half to
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH v2] chardev: Use timer instead of bottom-half to postpone open event |
Date: |
Wed, 31 Oct 2012 22:49:14 +0100 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
On Wed, Oct 31, 2012 at 02:23:15PM +0100, Jan Kiszka wrote:
> On 2012-10-12 09:52, Jan Kiszka wrote:
> > As the block layer may decide to flush bottom-halfs while the machine is
> > still initializing (e.g. to read geometry data from the disk), our
> > postponed open event may be processed before the last frontend
> > registered with a muxed chardev.
> >
> > Until the semantics of BHs have been clarified, use an expired timer to
> > achieve the same effect (suggested by Paolo Bonzini). This requires to
> > perform the alarm timer initialization earlier as otherwise timer
> > subsystem can be used before being ready.
> >
> > Signed-off-by: Jan Kiszka <address@hidden>
> > ---
> >
> > Changes in v2:
> > - Move init_alarm_timer call to fix e.g. -monitor stdio
>
> Ping?
>
> Jan
>
> >
> > qemu-char.c | 13 +++++++------
> > qemu-char.h | 2 +-
> > vl.c | 10 +++++-----
> > 3 files changed, 13 insertions(+), 12 deletions(-)
> >
> > diff --git a/qemu-char.c b/qemu-char.c
> > index b082bae..d8eed21 100644
> > --- a/qemu-char.c
> > +++ b/qemu-char.c
> > @@ -123,19 +123,20 @@ void qemu_chr_be_event(CharDriverState *s, int event)
> > s->chr_event(s->handler_opaque, event);
> > }
> >
> > -static void qemu_chr_generic_open_bh(void *opaque)
> > +static void qemu_chr_fire_open_event(void *opaque)
> > {
> > CharDriverState *s = opaque;
> > qemu_chr_be_event(s, CHR_EVENT_OPENED);
> > - qemu_bh_delete(s->bh);
> > - s->bh = NULL;
> > + qemu_free_timer(s->open_timer);
> > + s->open_timer = NULL;
> > }
> >
> > void qemu_chr_generic_open(CharDriverState *s)
> > {
> > - if (s->bh == NULL) {
> > - s->bh = qemu_bh_new(qemu_chr_generic_open_bh, s);
> > - qemu_bh_schedule(s->bh);
> > + if (s->open_timer == NULL) {
> > + s->open_timer = qemu_new_timer_ms(vm_clock,
> > + qemu_chr_fire_open_event, s);
> > + qemu_mod_timer(s->open_timer, qemu_get_clock_ms(vm_clock) - 1);
> > }
> > }
> >
> > diff --git a/qemu-char.h b/qemu-char.h
> > index 486644b..297dd98 100644
> > --- a/qemu-char.h
> > +++ b/qemu-char.h
> > @@ -69,7 +69,7 @@ struct CharDriverState {
> > void (*chr_guest_open)(struct CharDriverState *chr);
> > void (*chr_guest_close)(struct CharDriverState *chr);
> > void *opaque;
> > - QEMUBH *bh;
> > + QEMUTimer *open_timer;
> > char *label;
> > char *filename;
> > int opened;
> > diff --git a/vl.c b/vl.c
> > index 5b357a3..586773c 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -3439,6 +3439,11 @@ int main(int argc, char **argv, char **envp)
> > add_device_config(DEV_VIRTCON, "vc:80Cx24C");
> > }
> >
> > + if (init_timer_alarm() < 0) {
> > + fprintf(stderr, "could not initialize alarm timer\n");
> > + exit(1);
> > + }
> > +
> > socket_init();
> >
> > if (qemu_opts_foreach(qemu_find_opts("chardev"), chardev_init_func,
> > NULL, 1) != 0)
> > @@ -3506,11 +3511,6 @@ int main(int argc, char **argv, char **envp)
> >
> > os_set_line_buffering();
> >
> > - if (init_timer_alarm() < 0) {
> > - fprintf(stderr, "could not initialize alarm timer\n");
> > - exit(1);
> > - }
> > -
> > #ifdef CONFIG_SPICE
> > /* spice needs the timers to be initialized by this point */
> > qemu_spice_init();
> >
>
>
Applied.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net