Make the event handling tasklet per channel rather than per-cpu.
This allows for better fairness when getting lots of data on the same
cpu.
Signed-off-by: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
---
drivers/hv/channel.c | 2 +-
drivers/hv/channel_mgmt.c | 16 +++++-----
drivers/hv/connection.c | 78 ++---------------------------------------------
drivers/hv/hv.c | 2 --
drivers/hv/hyperv_vmbus.h | 1 -
drivers/hv/vmbus_drv.c | 58 ++++++++++++++++++++++++++++++-----
include/linux/hyperv.h | 3 +-
7 files changed, 64 insertions(+), 96 deletions(-)
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index 789c75f6df26..18cc1c78260d 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -530,7 +530,7 @@ static int vmbus_close_internal(struct vmbus_channel *channel)
int ret;
/*
- * process_chn_event(), running in the tasklet, can race
+ * vmbus_on_event(), running in the tasklet, can race
* with vmbus_close_internal() in the case of SMP guest, e.g., when
* the former is accessing channel->inbound.ring_buffer, the latter
* could be freeing the ring_buffer pages.
diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c
index 579ad2560a39..2f6270d76b79 100644
--- a/drivers/hv/channel_mgmt.c
+++ b/drivers/hv/channel_mgmt.c
@@ -339,6 +339,9 @@ static struct vmbus_channel *alloc_channel(void)
INIT_LIST_HEAD(&channel->sc_list);
INIT_LIST_HEAD(&channel->percpu_list);
+ tasklet_init(&channel->callback_event,
+ vmbus_on_event, (unsigned long)channel);
+
return channel;
}
@@ -347,6 +350,7 @@ static struct vmbus_channel *alloc_channel(void)
*/
static void free_channel(struct vmbus_channel *channel)
{
+ tasklet_kill(&channel->callback_event);
kfree(channel);
}
@@ -380,21 +384,15 @@ static void vmbus_release_relid(u32 relid)
void hv_event_tasklet_disable(struct vmbus_channel *channel)
{
- struct hv_per_cpu_context *hv_cpu;
-
- hv_cpu = per_cpu_ptr(hv_context.cpu_context, channel->target_cpu);
- tasklet_disable(&hv_cpu->event_dpc);
+ tasklet_disable(&channel->callback_event);
}
void hv_event_tasklet_enable(struct vmbus_channel *channel)
{
- struct hv_per_cpu_context *hv_cpu;
-
- hv_cpu = per_cpu_ptr(hv_context.cpu_context, channel->target_cpu);
- tasklet_enable(&hv_cpu->event_dpc);
+ tasklet_enable(&channel->callback_event);
/* In case there is any pending event */
- tasklet_schedule(&hv_cpu->event_dpc);
+ tasklet_schedule(&channel->callback_event);
}
void hv_process_channel_removal(struct vmbus_channel *channel, u32 relid)
diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c
index 158f12823baf..27e72dc07e12 100644
--- a/drivers/hv/connection.c
+++ b/drivers/hv/connection.c
@@ -260,29 +260,6 @@ void vmbus_disconnect(void)
}
/*
- * Map the given relid to the corresponding channel based on the
- * per-cpu list of channels that have been affinitized to this CPU.
- * This will be used in the channel callback path as we can do this
- * mapping in a lock-free fashion.
- */
-static struct vmbus_channel *pcpu_relid2channel(u32 relid)
-{
- struct hv_per_cpu_context *hv_cpu
- = this_cpu_ptr(hv_context.cpu_context);
- struct vmbus_channel *found_channel = NULL;
- struct vmbus_channel *channel;
-
- list_for_each_entry(channel, &hv_cpu->chan_list, percpu_list) {
- if (channel->offermsg.child_relid == relid) {
- found_channel = channel;
- break;
- }
- }
-
- return found_channel;
-}
-
-/*
* relid2channel - Get the channel object given its
* child relative id (ie channel id)
*/
@@ -318,25 +295,16 @@ struct vmbus_channel *relid2channel(u32 relid)
}
/*
- * process_chn_event - Process a channel event notification
+ * vmbus_on_event - Process a channel event notification
*/
-static void process_chn_event(u32 relid)
+void vmbus_on_event(unsigned long data)
{
- struct vmbus_channel *channel;
+ struct vmbus_channel *channel = (void *) data;
void *arg;
bool read_state;
u32 bytes_to_read;
/*
- * Find the channel based on this relid and invokes the
- * channel callback to process the event
- */
- channel = pcpu_relid2channel(relid);
-
- if (!channel)
- return;
-
- /*
* A channel once created is persistent even when there
* is no driver handling the device. An unloading driver
* sets the onchannel_callback to NULL on the same CPU
@@ -344,7 +312,6 @@ static void process_chn_event(u32 relid)
* Thus, checking and invoking the driver specific callback takes
* care of orderly unloading of the driver.
*/
-
if (channel->onchannel_callback != NULL) {
arg = channel->channel_callback_context;
read_state = channel->batched_reading;
@@ -373,45 +340,6 @@ static void process_chn_event(u32 relid)
}
/*
- * vmbus_on_event - Handler for events
- */
-void vmbus_on_event(unsigned long data)
-{
- struct hv_per_cpu_context *hv_cpu = (void *)data;
- unsigned long *recv_int_page;
- u32 maxbits, relid;
-
- if (vmbus_proto_version < VERSION_WIN8) {
- maxbits = MAX_NUM_CHANNELS_SUPPORTED;
- recv_int_page = vmbus_connection.recv_int_page;
- } else {
- /*
- * When the host is win8 and beyond, the event page
- * can be directly checked to get the id of the channel
- * that has the interrupt pending.
- */
- void *page_addr = hv_cpu->synic_event_page;
- union hv_synic_event_flags *event
- = (union hv_synic_event_flags *)page_addr +
- VMBUS_MESSAGE_SINT;
-
- maxbits = HV_EVENT_FLAGS_COUNT;
- recv_int_page = event->flags;
- }
-
- if (unlikely(!recv_int_page))
- return;
-
- for_each_set_bit(relid, recv_int_page, maxbits) {
- if (sync_test_and_clear_bit(relid, recv_int_page)) {
- /* Special case - vmbus channel protocol msg */
- if (relid != 0)
- process_chn_event(relid);
- }
- }
-}
-
-/*
* vmbus_post_msg - Send a msg on the vmbus's message connection
*/
int vmbus_post_msg(void *buffer, size_t buflen, bool can_sleep)
diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 9fc2355a60ea..665a64f1611e 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -156,8 +156,6 @@ int hv_synic_alloc(void)
= per_cpu_ptr(hv_context.cpu_context, cpu);
memset(hv_cpu, 0, sizeof(*hv_cpu));
- tasklet_init(&hv_cpu->event_dpc,
- vmbus_on_event, (unsigned long) hv_cpu);
tasklet_init(&hv_cpu->msg_dpc,
vmbus_on_msg_dpc, (unsigned long) hv_cpu);
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
index c8ce9ab2e16a..558a798c407c 100644
--- a/drivers/hv/hyperv_vmbus.h
+++ b/drivers/hv/hyperv_vmbus.h
@@ -206,7 +206,6 @@ struct hv_per_cpu_context {
* we will manage the tasklet that handles events messages on a per CPU
* basis.
*/
- struct tasklet_struct event_dpc;
struct tasklet_struct msg_dpc;
/*
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index cf8540c1df4a..eaf1a10b0245 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -885,6 +885,56 @@ void vmbus_on_msg_dpc(unsigned long data)
vmbus_signal_eom(msg, message_type);
}
+
+/*
+ * Schedule all channels with events pending
+ */
+static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu)
+{
+ unsigned long *recv_int_page;
+ u32 maxbits, relid;
+
+ if (vmbus_proto_version < VERSION_WIN8) {
+ maxbits = MAX_NUM_CHANNELS_SUPPORTED;
+ recv_int_page = vmbus_connection.recv_int_page;
+ } else {
+ /*
+ * When the host is win8 and beyond, the event page
+ * can be directly checked to get the id of the channel
+ * that has the interrupt pending.
+ */
+ void *page_addr = hv_cpu->synic_event_page;
+ union hv_synic_event_flags *event
+ = (union hv_synic_event_flags *)page_addr +
+ VMBUS_MESSAGE_SINT;
+
+ maxbits = HV_EVENT_FLAGS_COUNT;
+ recv_int_page = event->flags;
+ }
+
+ if (unlikely(!recv_int_page))
+ return;
+
+ for_each_set_bit(relid, recv_int_page, maxbits) {
+ struct vmbus_channel *channel;
+
+ if (!sync_test_and_clear_bit(relid, recv_int_page))
+ continue;
+
+ /* Special case - vmbus channel protocol msg */
+ if (relid == 0)
+ continue;
+
+ /* Find channel based on relid */
+ list_for_each_entry(channel, &hv_cpu->chan_list, percpu_list) {
+ if (channel->offermsg.child_relid == relid) {
+ tasklet_schedule(&channel->callback_event);
+ break;
+ }
+ }
+ }
+}
+
static void vmbus_isr(void)
{
struct hv_per_cpu_context *hv_cpu
@@ -922,8 +972,7 @@ static void vmbus_isr(void)
}
if (handled)
- tasklet_schedule(&hv_cpu->event_dpc);
-
+ vmbus_chan_sched(hv_cpu);
page_addr = hv_cpu->synic_message_page;
msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
@@ -1536,12 +1585,7 @@ static void __exit vmbus_exit(void)
&hyperv_panic_block);
}
bus_unregister(&hv_bus);
- for_each_online_cpu(cpu) {
- struct hv_per_cpu_context *hv_cpu
- = per_cpu_ptr(hv_context.cpu_context, cpu);
- tasklet_kill(&hv_cpu->event_dpc);
- }
cpuhp_remove_state(hyperv_cpuhp_online);
hv_synic_free();
acpi_bus_unregister_driver(&vmbus_acpi_driver);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index b30808f740f9..dce5aa6751b4 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -35,7 +35,7 @@
#include <linux/completion.h>
#include <linux/device.h>
#include <linux/mod_devicetable.h>
-
+#include <linux/interrupt.h>
#define MAX_PAGE_BUFFER_COUNT 32
#define MAX_MULTIPAGE_BUFFER_COUNT 32 /* 128K */
@@ -729,6 +729,7 @@ struct vmbus_channel {
struct vmbus_close_msg close_msg;
/* Channel callback's invoked in softirq context */
+ struct tasklet_struct callback_event;
void (*onchannel_callback)(void *context);
void *channel_callback_context;
--
2.11.0
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