Revision 6e474083f3daf3a3546737f5d7d502ad12eb257c authored by Wei Xu on 01 December 2017, 10:10:36 UTC, committed by David S. Miller on 03 December 2017, 02:31:03 UTC
Matthew found a roughly 40% tcp throughput regression with commit c67df11f(vhost_net: try batch dequing from skb array) as discussed in the following thread: https://www.mail-archive.com/netdev@vger.kernel.org/msg187936.html Eventually we figured out that it was a skb leak in handle_rx() when sending packets to the VM. This usually happens when a guest can not drain out vq as fast as vhost fills in, afterwards it sets off the traffic jam and leaks skb(s) which occurs as no headcount to send on the vq from vhost side. This can be avoided by making sure we have got enough headcount before actually consuming a skb from the batched rx array while transmitting, which is simply done by moving checking the zero headcount a bit ahead. Signed-off-by: Wei Xu <wexu@redhat.com> Reported-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent fa935ca
i2c-core-of.c
/*
* Linux I2C core OF support code
*
* Copyright (C) 2008 Jochen Friedrich <jochen@scram.de>
* based on a previous patch from Jon Smirl <jonsmirl@gmail.com>
*
* Copyright (C) 2013 Wolfram Sang <wsa@the-dreams.de>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*/
#include <dt-bindings/i2c/i2c.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include "i2c-core.h"
static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
struct device_node *node)
{
struct i2c_client *result;
struct i2c_board_info info = {};
struct dev_archdata dev_ad = {};
const __be32 *addr_be;
u32 addr;
int len;
dev_dbg(&adap->dev, "of_i2c: register %pOF\n", node);
if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
dev_err(&adap->dev, "of_i2c: modalias failure on %pOF\n",
node);
return ERR_PTR(-EINVAL);
}
addr_be = of_get_property(node, "reg", &len);
if (!addr_be || (len < sizeof(*addr_be))) {
dev_err(&adap->dev, "of_i2c: invalid reg on %pOF\n", node);
return ERR_PTR(-EINVAL);
}
addr = be32_to_cpup(addr_be);
if (addr & I2C_TEN_BIT_ADDRESS) {
addr &= ~I2C_TEN_BIT_ADDRESS;
info.flags |= I2C_CLIENT_TEN;
}
if (addr & I2C_OWN_SLAVE_ADDRESS) {
addr &= ~I2C_OWN_SLAVE_ADDRESS;
info.flags |= I2C_CLIENT_SLAVE;
}
if (i2c_check_addr_validity(addr, info.flags)) {
dev_err(&adap->dev, "of_i2c: invalid addr=%x on %pOF\n",
addr, node);
return ERR_PTR(-EINVAL);
}
info.addr = addr;
info.of_node = of_node_get(node);
info.archdata = &dev_ad;
if (of_property_read_bool(node, "host-notify"))
info.flags |= I2C_CLIENT_HOST_NOTIFY;
if (of_get_property(node, "wakeup-source", NULL))
info.flags |= I2C_CLIENT_WAKE;
result = i2c_new_device(adap, &info);
if (result == NULL) {
dev_err(&adap->dev, "of_i2c: Failure registering %pOF\n", node);
of_node_put(node);
return ERR_PTR(-EINVAL);
}
return result;
}
void of_i2c_register_devices(struct i2c_adapter *adap)
{
struct device_node *bus, *node;
struct i2c_client *client;
/* Only register child devices if the adapter has a node pointer set */
if (!adap->dev.of_node)
return;
dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
bus = of_get_child_by_name(adap->dev.of_node, "i2c-bus");
if (!bus)
bus = of_node_get(adap->dev.of_node);
for_each_available_child_of_node(bus, node) {
if (of_node_test_and_set_flag(node, OF_POPULATED))
continue;
client = of_i2c_register_device(adap, node);
if (IS_ERR(client)) {
dev_warn(&adap->dev,
"Failed to create I2C device for %pOF\n",
node);
of_node_clear_flag(node, OF_POPULATED);
}
}
of_node_put(bus);
}
static int of_dev_node_match(struct device *dev, void *data)
{
return dev->of_node == data;
}
/* must call put_device() when done with returned i2c_client device */
struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
{
struct device *dev;
struct i2c_client *client;
dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
if (!dev)
return NULL;
client = i2c_verify_client(dev);
if (!client)
put_device(dev);
return client;
}
EXPORT_SYMBOL(of_find_i2c_device_by_node);
/* must call put_device() when done with returned i2c_adapter device */
struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
{
struct device *dev;
struct i2c_adapter *adapter;
dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
if (!dev)
return NULL;
adapter = i2c_verify_adapter(dev);
if (!adapter)
put_device(dev);
return adapter;
}
EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
/* must call i2c_put_adapter() when done with returned i2c_adapter device */
struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
{
struct i2c_adapter *adapter;
adapter = of_find_i2c_adapter_by_node(node);
if (!adapter)
return NULL;
if (!try_module_get(adapter->owner)) {
put_device(&adapter->dev);
adapter = NULL;
}
return adapter;
}
EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
static const struct of_device_id*
i2c_of_match_device_sysfs(const struct of_device_id *matches,
struct i2c_client *client)
{
const char *name;
for (; matches->compatible[0]; matches++) {
/*
* Adding devices through the i2c sysfs interface provides us
* a string to match which may be compatible with the device
* tree compatible strings, however with no actual of_node the
* of_match_device() will not match
*/
if (sysfs_streq(client->name, matches->compatible))
return matches;
name = strchr(matches->compatible, ',');
if (!name)
name = matches->compatible;
else
name++;
if (sysfs_streq(client->name, name))
return matches;
}
return NULL;
}
const struct of_device_id
*i2c_of_match_device(const struct of_device_id *matches,
struct i2c_client *client)
{
const struct of_device_id *match;
if (!(client && matches))
return NULL;
match = of_match_device(matches, &client->dev);
if (match)
return match;
return i2c_of_match_device_sysfs(matches, client);
}
EXPORT_SYMBOL_GPL(i2c_of_match_device);
#if IS_ENABLED(CONFIG_OF_DYNAMIC)
static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
void *arg)
{
struct of_reconfig_data *rd = arg;
struct i2c_adapter *adap;
struct i2c_client *client;
switch (of_reconfig_get_state_change(action, rd)) {
case OF_RECONFIG_CHANGE_ADD:
adap = of_find_i2c_adapter_by_node(rd->dn->parent);
if (adap == NULL)
return NOTIFY_OK; /* not for us */
if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
put_device(&adap->dev);
return NOTIFY_OK;
}
client = of_i2c_register_device(adap, rd->dn);
put_device(&adap->dev);
if (IS_ERR(client)) {
dev_err(&adap->dev, "failed to create client for '%pOF'\n",
rd->dn);
of_node_clear_flag(rd->dn, OF_POPULATED);
return notifier_from_errno(PTR_ERR(client));
}
break;
case OF_RECONFIG_CHANGE_REMOVE:
/* already depopulated? */
if (!of_node_check_flag(rd->dn, OF_POPULATED))
return NOTIFY_OK;
/* find our device by node */
client = of_find_i2c_device_by_node(rd->dn);
if (client == NULL)
return NOTIFY_OK; /* no? not meant for us */
/* unregister takes one ref away */
i2c_unregister_device(client);
/* and put the reference of the find */
put_device(&client->dev);
break;
}
return NOTIFY_OK;
}
struct notifier_block i2c_of_notifier = {
.notifier_call = of_i2c_notify,
};
#endif /* CONFIG_OF_DYNAMIC */
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