Date: Fri, 14 Oct 2016 09:00:29 +0000 (UTC) From: Sepherosa Ziehau <sephe@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r307309 - stable/11/sys/dev/hyperv/vmbus Message-ID: <201610140900.u9E90TXo001911@repo.freebsd.org>
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Author: sephe Date: Fri Oct 14 09:00:29 2016 New Revision: 307309 URL: https://svnweb.freebsd.org/changeset/base/307309 Log: MFC 302710,302713 302710 hyperv/vmbus: Remove unnecessary callback check. Sponsored by: Microsoft OSTC Differential Revision: https://reviews.freebsd.org/D7046 302713 hyperv/vmbus: Install different task function for batch/non-batch channels This avoids bunch of unnecessary checks on hot path and simplifies the channel processing. Sponsored by: Microsoft OSTC Differential Revision: https://reviews.freebsd.org/D7085 Modified: stable/11/sys/dev/hyperv/vmbus/hv_channel.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/dev/hyperv/vmbus/hv_channel.c ============================================================================== --- stable/11/sys/dev/hyperv/vmbus/hv_channel.c Fri Oct 14 08:55:49 2016 (r307308) +++ stable/11/sys/dev/hyperv/vmbus/hv_channel.c Fri Oct 14 09:00:29 2016 (r307309) @@ -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), @@ -846,46 +853,48 @@ 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; + + arg = chan->channel_callback_context; + callback = chan->on_channel_callback; + + /* + * Optimize host to guest signaling by ensuring: + * 1. While reading the channel, we disable interrupts from + * host. + * 2. Ensure that we process all posted messages from the host + * before returning from this callback. + * 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. + */ + for (;;) { + uint32_t left; - if (channel->ch_flags & VMBUS_CHAN_FLAG_BATCHREAD) - is_batched_reading = true; + callback(arg); - if (channel->on_channel_callback != NULL) { - arg = channel->channel_callback_context; - /* - * Optimize host to guest signaling by ensuring: - * 1. While reading the channel, we disable interrupts from - * host. - * 2. Ensure that we process all posted messages from the host - * before returning from this callback. - * 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. - */ - do { - if (is_batched_reading) - hv_ring_buffer_read_begin(&channel->inbound); + 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); + } +} - channel->on_channel_callback(arg); +static void +vmbus_chan_task_nobatch(void *xchan, int pending __unused) +{ + struct hv_vmbus_channel *chan = xchan; - 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)); - } + chan->on_channel_callback(chan->channel_callback_context); } static __inline void
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