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
pxa2xx_viper.c
/*
* Viper/Zeus PCMCIA support
* Copyright 2004 Arcom Control Systems
*
* Maintained by Marc Zyngier <maz@misterjones.org>
*
* Based on:
* iPAQ h2200 PCMCIA support
* Copyright 2004 Koen Kooi <koen@vestingbar.nl>
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file COPYING in the main directory of this archive for
* more details.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <pcmcia/ss.h>
#include <asm/irq.h>
#include <linux/platform_data/pcmcia-pxa2xx_viper.h>
#include "soc_common.h"
#include "pxa2xx_base.h"
static struct platform_device *arcom_pcmcia_dev;
static inline struct arcom_pcmcia_pdata *viper_get_pdata(void)
{
return arcom_pcmcia_dev->dev.platform_data;
}
static int viper_pcmcia_hw_init(struct soc_pcmcia_socket *skt)
{
struct arcom_pcmcia_pdata *pdata = viper_get_pdata();
unsigned long flags;
skt->stat[SOC_STAT_CD].gpio = pdata->cd_gpio;
skt->stat[SOC_STAT_CD].name = "PCMCIA_CD";
skt->stat[SOC_STAT_RDY].gpio = pdata->rdy_gpio;
skt->stat[SOC_STAT_RDY].name = "CF ready";
if (gpio_request(pdata->pwr_gpio, "CF power"))
goto err_request_pwr;
local_irq_save(flags);
if (gpio_direction_output(pdata->pwr_gpio, 0)) {
local_irq_restore(flags);
goto err_dir;
}
local_irq_restore(flags);
return 0;
err_dir:
gpio_free(pdata->pwr_gpio);
err_request_pwr:
dev_err(&arcom_pcmcia_dev->dev, "Failed to setup PCMCIA GPIOs\n");
return -1;
}
/*
* Release all resources.
*/
static void viper_pcmcia_hw_shutdown(struct soc_pcmcia_socket *skt)
{
struct arcom_pcmcia_pdata *pdata = viper_get_pdata();
gpio_free(pdata->pwr_gpio);
}
static void viper_pcmcia_socket_state(struct soc_pcmcia_socket *skt,
struct pcmcia_state *state)
{
state->vs_3v = 1; /* Can only apply 3.3V */
state->vs_Xv = 0;
}
static int viper_pcmcia_configure_socket(struct soc_pcmcia_socket *skt,
const socket_state_t *state)
{
struct arcom_pcmcia_pdata *pdata = viper_get_pdata();
/* Silently ignore Vpp, output enable, speaker enable. */
pdata->reset(state->flags & SS_RESET);
/* Apply socket voltage */
switch (state->Vcc) {
case 0:
gpio_set_value(pdata->pwr_gpio, 0);
break;
case 33:
gpio_set_value(pdata->pwr_gpio, 1);
break;
default:
dev_err(&arcom_pcmcia_dev->dev, "Unsupported Vcc:%d\n", state->Vcc);
return -1;
}
return 0;
}
static struct pcmcia_low_level viper_pcmcia_ops = {
.owner = THIS_MODULE,
.hw_init = viper_pcmcia_hw_init,
.hw_shutdown = viper_pcmcia_hw_shutdown,
.socket_state = viper_pcmcia_socket_state,
.configure_socket = viper_pcmcia_configure_socket,
.nr = 1,
};
static struct platform_device *viper_pcmcia_device;
static int viper_pcmcia_probe(struct platform_device *pdev)
{
int ret;
/* I can't imagine more than one device, but you never know... */
if (arcom_pcmcia_dev)
return -EEXIST;
if (!pdev->dev.platform_data)
return -EINVAL;
viper_pcmcia_device = platform_device_alloc("pxa2xx-pcmcia", -1);
if (!viper_pcmcia_device)
return -ENOMEM;
arcom_pcmcia_dev = pdev;
viper_pcmcia_device->dev.parent = &pdev->dev;
ret = platform_device_add_data(viper_pcmcia_device,
&viper_pcmcia_ops,
sizeof(viper_pcmcia_ops));
if (!ret)
ret = platform_device_add(viper_pcmcia_device);
if (ret) {
platform_device_put(viper_pcmcia_device);
arcom_pcmcia_dev = NULL;
}
return ret;
}
static int viper_pcmcia_remove(struct platform_device *pdev)
{
platform_device_unregister(viper_pcmcia_device);
arcom_pcmcia_dev = NULL;
return 0;
}
static struct platform_device_id viper_pcmcia_id_table[] = {
{ .name = "viper-pcmcia", },
{ .name = "zeus-pcmcia", },
{ },
};
static struct platform_driver viper_pcmcia_driver = {
.probe = viper_pcmcia_probe,
.remove = viper_pcmcia_remove,
.driver = {
.name = "arcom-pcmcia",
},
.id_table = viper_pcmcia_id_table,
};
module_platform_driver(viper_pcmcia_driver);
MODULE_DEVICE_TABLE(platform, viper_pcmcia_id_table);
MODULE_LICENSE("GPL");
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