From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:46136) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTgA5-0003Jk-9M for qemu-devel@nongnu.org; Wed, 31 Oct 2012 17:49:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TTgA3-0001vE-QW for qemu-devel@nongnu.org; Wed, 31 Oct 2012 17:49:21 -0400 Received: from hall.aurel32.net ([2001:470:1f15:c4f::1]:55842) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TTgA3-0001v6-F7 for qemu-devel@nongnu.org; Wed, 31 Oct 2012 17:49:19 -0400 Date: Wed, 31 Oct 2012 22:49:14 +0100 From: Aurelien Jarno Message-ID: <20121031214914.GC32197@hall.aurel32.net> References: <5073083C.1060201@siemens.com> <5077CC51.4080200@siemens.com> <50912643.7010302@siemens.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <50912643.7010302@siemens.com> Sender: Aurelien Jarno Subject: Re: [Qemu-devel] [PATCH v2] chardev: Use timer instead of bottom-half to postpone open event List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Peter Maydell , Anthony Liguori , qemu-devel , Paolo Bonzini 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 > > --- > > > > 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 aurelien@aurel32.net http://www.aurel32.net