[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v2] chardev: Use timer instead of bottom-half to
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [PATCH v2] chardev: Use timer instead of bottom-half to postpone open event |
Date: |
Wed, 31 Oct 2012 14:23:15 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
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();
>
--
Siemens AG, Corporate Technology, CT RTC ITP SDP-DE
Corporate Competence Center Embedded Linux