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hyperv/vmbus: Install different task function for batch/non-batch channels

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This avoids bunch of unnecessary checks on hot path and simplifies the
channel processing.

MFC after:	1 week
Sponsored by:	Microsoft OSTC
Differential Revision:	https://reviews.freebsd.org/D7085
This commit is contained in:
sephe 2016-07-13 08:30:14 +00:00
parent 393b9a1b9a
commit 5f2e1502f8
1 changed files with 35 additions and 24 deletions
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59
sys/dev/hyperv/vmbus/hv_channel.c
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@ -51,9 +51,10 @@ __FBSDID("$FreeBSD$");
#include <dev/hyperv/vmbus/vmbus_var.h>
static void vmbus_channel_set_event(hv_vmbus_channel* channel);
static void VmbusProcessChannelEvent(void* channel, int pending);
static void vmbus_chan_update_evtflagcnt(struct vmbus_softc *,
const struct hv_vmbus_channel *);
static void vmbus_chan_task(void *, int);
static void vmbus_chan_task_nobatch(void *, int);
/**
* @brief Trigger an event notification on the specified channel
@ -213,7 +214,13 @@ hv_vmbus_channel_open(
new_channel->rxq = VMBUS_PCPU_GET(new_channel->vmbus_sc, event_tq,
new_channel->target_cpu);
TASK_INIT(&new_channel->channel_task, 0, VmbusProcessChannelEvent, new_channel);
if (new_channel->ch_flags & VMBUS_CHAN_FLAG_BATCHREAD) {
TASK_INIT(&new_channel->channel_task, 0,
vmbus_chan_task, new_channel);
} else {
TASK_INIT(&new_channel->channel_task, 0,
vmbus_chan_task_nobatch, new_channel);
}
/* Allocate the ring buffer */
out = contigmalloc((send_ring_buffer_size + recv_ring_buffer_size),
@ -846,22 +853,16 @@ hv_vmbus_channel_recv_packet_raw(
return (0);
}
/**
* Process a channel event notification
*/
static void
VmbusProcessChannelEvent(void* context, int pending)
vmbus_chan_task(void *xchan, int pending __unused)
{
void* arg;
uint32_t bytes_to_read;
hv_vmbus_channel* channel = (hv_vmbus_channel*)context;
bool is_batched_reading = false;
struct hv_vmbus_channel *chan = xchan;
void (*callback)(void *);
void *arg;
if (channel->ch_flags & VMBUS_CHAN_FLAG_BATCHREAD)
is_batched_reading = true;
arg = chan->channel_callback_context;
callback = chan->on_channel_callback;
arg = channel->channel_callback_context;
/*
* Optimize host to guest signaling by ensuring:
* 1. While reading the channel, we disable interrupts from
@ -871,19 +872,29 @@ VmbusProcessChannelEvent(void* context, int pending)
* 3. Once we return, enable signaling from the host. Once this
* state is set we check to see if additional packets are
* available to read. In this case we repeat the process.
*
* NOTE: Interrupt has been disabled in the ISR.
*/
do {
if (is_batched_reading)
hv_ring_buffer_read_begin(&channel->inbound);
for (;;) {
uint32_t left;
channel->on_channel_callback(arg);
callback(arg);
if (is_batched_reading)
bytes_to_read =
hv_ring_buffer_read_end(&channel->inbound);
else
bytes_to_read = 0;
} while (is_batched_reading && (bytes_to_read != 0));
left = hv_ring_buffer_read_end(&chan->inbound);
if (left == 0) {
/* No more data in RX bufring; done */
break;
}
hv_ring_buffer_read_begin(&chan->inbound);
}
}
static void
vmbus_chan_task_nobatch(void *xchan, int pending __unused)
{
struct hv_vmbus_channel *chan = xchan;
chan->on_channel_callback(chan->channel_callback_context);
}
static __inline void