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
isl29020.c
/*
* isl29020.c - Intersil ALS Driver
*
* Copyright (C) 2008 Intel Corp
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* 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; version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* Data sheet at: http://www.intersil.com/data/fn/fn6505.pdf
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/sysfs.h>
#include <linux/pm_runtime.h>
static DEFINE_MUTEX(mutex);
static ssize_t als_sensing_range_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
int val;
val = i2c_smbus_read_byte_data(client, 0x00);
if (val < 0)
return val;
return sprintf(buf, "%d000\n", 1 << (2 * (val & 3)));
}
static ssize_t als_lux_input_data_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct i2c_client *client = to_i2c_client(dev);
int ret_val, val;
unsigned long int lux;
int temp;
pm_runtime_get_sync(dev);
msleep(100);
mutex_lock(&mutex);
temp = i2c_smbus_read_byte_data(client, 0x02); /* MSB data */
if (temp < 0) {
pm_runtime_put_sync(dev);
mutex_unlock(&mutex);
return temp;
}
ret_val = i2c_smbus_read_byte_data(client, 0x01); /* LSB data */
mutex_unlock(&mutex);
if (ret_val < 0) {
pm_runtime_put_sync(dev);
return ret_val;
}
ret_val |= temp << 8;
val = i2c_smbus_read_byte_data(client, 0x00);
pm_runtime_put_sync(dev);
if (val < 0)
return val;
lux = ((((1 << (2 * (val & 3))))*1000) * ret_val) / 65536;
return sprintf(buf, "%ld\n", lux);
}
static ssize_t als_sensing_range_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct i2c_client *client = to_i2c_client(dev);
int ret_val;
unsigned long val;
ret_val = kstrtoul(buf, 10, &val);
if (ret_val)
return ret_val;
if (val < 1 || val > 64000)
return -EINVAL;
/* Pick the smallest sensor range that will meet our requirements */
if (val <= 1000)
val = 1;
else if (val <= 4000)
val = 2;
else if (val <= 16000)
val = 3;
else
val = 4;
ret_val = i2c_smbus_read_byte_data(client, 0x00);
if (ret_val < 0)
return ret_val;
ret_val &= 0xFC; /*reset the bit before setting them */
ret_val |= val - 1;
ret_val = i2c_smbus_write_byte_data(client, 0x00, ret_val);
if (ret_val < 0)
return ret_val;
return count;
}
static void als_set_power_state(struct i2c_client *client, int enable)
{
int ret_val;
ret_val = i2c_smbus_read_byte_data(client, 0x00);
if (ret_val < 0)
return;
if (enable)
ret_val |= 0x80;
else
ret_val &= 0x7F;
i2c_smbus_write_byte_data(client, 0x00, ret_val);
}
static DEVICE_ATTR(lux0_sensor_range, S_IRUGO | S_IWUSR,
als_sensing_range_show, als_sensing_range_store);
static DEVICE_ATTR(lux0_input, S_IRUGO, als_lux_input_data_show, NULL);
static struct attribute *mid_att_als[] = {
&dev_attr_lux0_sensor_range.attr,
&dev_attr_lux0_input.attr,
NULL
};
static const struct attribute_group m_als_gr = {
.name = "isl29020",
.attrs = mid_att_als
};
static int als_set_default_config(struct i2c_client *client)
{
int retval;
retval = i2c_smbus_write_byte_data(client, 0x00, 0xc0);
if (retval < 0) {
dev_err(&client->dev, "default write failed.");
return retval;
}
return 0;
}
static int isl29020_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
int res;
res = als_set_default_config(client);
if (res < 0)
return res;
res = sysfs_create_group(&client->dev.kobj, &m_als_gr);
if (res) {
dev_err(&client->dev, "isl29020: device create file failed\n");
return res;
}
dev_info(&client->dev, "%s isl29020: ALS chip found\n", client->name);
als_set_power_state(client, 0);
pm_runtime_enable(&client->dev);
return res;
}
static int isl29020_remove(struct i2c_client *client)
{
sysfs_remove_group(&client->dev.kobj, &m_als_gr);
return 0;
}
static const struct i2c_device_id isl29020_id[] = {
{ "isl29020", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, isl29020_id);
#ifdef CONFIG_PM
static int isl29020_runtime_suspend(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
als_set_power_state(client, 0);
return 0;
}
static int isl29020_runtime_resume(struct device *dev)
{
struct i2c_client *client = to_i2c_client(dev);
als_set_power_state(client, 1);
return 0;
}
static const struct dev_pm_ops isl29020_pm_ops = {
.runtime_suspend = isl29020_runtime_suspend,
.runtime_resume = isl29020_runtime_resume,
};
#define ISL29020_PM_OPS (&isl29020_pm_ops)
#else /* CONFIG_PM */
#define ISL29020_PM_OPS NULL
#endif /* CONFIG_PM */
static struct i2c_driver isl29020_driver = {
.driver = {
.name = "isl29020",
.pm = ISL29020_PM_OPS,
},
.probe = isl29020_probe,
.remove = isl29020_remove,
.id_table = isl29020_id,
};
module_i2c_driver(isl29020_driver);
MODULE_AUTHOR("Kalhan Trisal <kalhan.trisal@intel.com>");
MODULE_DESCRIPTION("Intersil isl29020 ALS Driver");
MODULE_LICENSE("GPL v2");
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