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Re: [Qemu-devel] [PATCH for-2.4 06/12] etsec: Flush queue when rx buffer
From: |
Fam Zheng |
Subject: |
Re: [Qemu-devel] [PATCH for-2.4 06/12] etsec: Flush queue when rx buffer is consumed |
Date: |
Tue, 14 Jul 2015 17:48:40 +0800 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
On Tue, 07/14 17:33, Jason Wang wrote:
>
>
> On 07/14/2015 03:53 PM, Fam Zheng wrote:
> > The BH will be scheduled when etsec->rx_buffer_len is becoming 0, which
> > is the condition of queuing.
> >
> > Signed-off-by: Fam Zheng <address@hidden>
>
> I suggest to squash this into patch 05/12 to unbreak bisection.
05/12 didn't change the logic, it just moved the semantics from returning 0 in
.can_receive() to .receive(). So I think it's OK to split to make reviewing
easier.
>
> And can we do this without a bh? Otherwise, we may need to stop and
> restart the bh during vm stop and start?
A bh doesn't hurt when vm stop and restart (we get superfluous flush),
otherwise the call stack could go very deap with a long queue, something like:
etsec_receive
etsec_rx_ring_write
etsec_walk_rx_ring
etsec_flush_rx_queue
qemu_flush_queued_packets
...
etsec_receive
etsec_rx_ring_write
etsec_walk_rx_ring
etsec_flush_rx_queue
qemu_flush_queued_packets
/* loop */
...
>
> > ---
> > hw/net/fsl_etsec/etsec.c | 9 +++++++++
> > hw/net/fsl_etsec/etsec.h | 2 ++
> > hw/net/fsl_etsec/rings.c | 1 +
> > 3 files changed, 12 insertions(+)
> >
> > diff --git a/hw/net/fsl_etsec/etsec.c b/hw/net/fsl_etsec/etsec.c
> > index f5170ae..fcde9b4 100644
> > --- a/hw/net/fsl_etsec/etsec.c
> > +++ b/hw/net/fsl_etsec/etsec.c
> > @@ -366,6 +366,13 @@ static NetClientInfo net_etsec_info = {
> > .link_status_changed = etsec_set_link_status,
> > };
> >
> > +static void etsec_flush_rx_queue(void *opaque)
> > +{
> > + eTSEC *etsec = opaque;
> > +
> > + qemu_flush_queued_packets(qemu_get_queue(etsec->nic));
> > +}
> > +
> > static void etsec_realize(DeviceState *dev, Error **errp)
> > {
> > eTSEC *etsec = ETSEC_COMMON(dev);
> > @@ -378,6 +385,8 @@ static void etsec_realize(DeviceState *dev, Error
> > **errp)
> > etsec->bh = qemu_bh_new(etsec_timer_hit, etsec);
> > etsec->ptimer = ptimer_init(etsec->bh);
> > ptimer_set_freq(etsec->ptimer, 100);
> > +
> > + etsec->flush_bh = qemu_bh_new(etsec_flush_rx_queue, etsec);
> > }
> >
> > static void etsec_instance_init(Object *obj)
> > diff --git a/hw/net/fsl_etsec/etsec.h b/hw/net/fsl_etsec/etsec.h
> > index fc41773..05bb7f8 100644
> > --- a/hw/net/fsl_etsec/etsec.h
> > +++ b/hw/net/fsl_etsec/etsec.h
> > @@ -144,6 +144,8 @@ typedef struct eTSEC {
> > QEMUBH *bh;
> > struct ptimer_state *ptimer;
> >
> > + QEMUBH *flush_bh;
> > +
> > } eTSEC;
> >
> > #define TYPE_ETSEC_COMMON "eTSEC"
> > diff --git a/hw/net/fsl_etsec/rings.c b/hw/net/fsl_etsec/rings.c
> > index a11280b..7aae93e 100644
> > --- a/hw/net/fsl_etsec/rings.c
> > +++ b/hw/net/fsl_etsec/rings.c
> > @@ -646,6 +646,7 @@ void etsec_walk_rx_ring(eTSEC *etsec, int ring_nbr)
> > } else {
> > etsec->rx_buffer_len = 0;
> > etsec->rx_buffer = NULL;
> > + qemu_bh_schedule(etsec->flush_bh);
> > }
> >
> > RING_DEBUG("eTSEC End of ring_write: remaining_data:%zu\n",
> > remaining_data);
>
- [Qemu-devel] [PATCH for-2.4 00/12] hw/net: Fix .can_receive() for NICs, Fam Zheng, 2015/07/14
- [Qemu-devel] [PATCH for-2.4 01/12] xgmac: Drop packets with eth_can_rx is false., Fam Zheng, 2015/07/14
- [Qemu-devel] [PATCH for-2.4 02/12] pcnet: Drop pcnet_can_receive, Fam Zheng, 2015/07/14
- [Qemu-devel] [PATCH for-2.4 03/12] eepro100: Drop nic_can_receive, Fam Zheng, 2015/07/14
- [Qemu-devel] [PATCH for-2.4 04/12] usbnet: Drop usbnet_can_receive, Fam Zheng, 2015/07/14
- [Qemu-devel] [PATCH for-2.4 05/12] etsec: Move etsec_can_receive into etsec_receive, Fam Zheng, 2015/07/14
- [Qemu-devel] [PATCH for-2.4 06/12] etsec: Flush queue when rx buffer is consumed, Fam Zheng, 2015/07/14
[Qemu-devel] [PATCH for-2.4 07/12] mcf_fec: Drop mcf_fec_can_receive, Fam Zheng, 2015/07/14
[Qemu-devel] [PATCH for-2.4 09/12] mipsnet: Flush queued packets when receiving is enabled, Fam Zheng, 2015/07/14
[Qemu-devel] [PATCH for-2.4 10/12] stellaris_enet: Flush queued packets when read done, Fam Zheng, 2015/07/14
[Qemu-devel] [PATCH for-2.4 11/12] dp8393x: Flush packets when link comes up, Fam Zheng, 2015/07/14
[Qemu-devel] [PATCH for-2.4 12/12] axienet: Flush queued packets when rx is done, Fam Zheng, 2015/07/14
[Qemu-devel] [PATCH for-2.4 08/12] milkymist-minimac2: Flush queued packets when link comes up, Fam Zheng, 2015/07/14