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_colibri.c
/*
* linux/drivers/pcmcia/pxa2xx_colibri.c
*
* Driver for Toradex Colibri PXA270 CF socket
*
* Copyright (C) 2010 Marek Vasut <marek.vasut@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <asm/mach-types.h>
#include "soc_common.h"
#define COLIBRI270_RESET_GPIO 53
#define COLIBRI270_PPEN_GPIO 107
#define COLIBRI270_BVD1_GPIO 83
#define COLIBRI270_BVD2_GPIO 82
#define COLIBRI270_DETECT_GPIO 84
#define COLIBRI270_READY_GPIO 1
#define COLIBRI320_RESET_GPIO 77
#define COLIBRI320_PPEN_GPIO 57
#define COLIBRI320_BVD1_GPIO 53
#define COLIBRI320_BVD2_GPIO 79
#define COLIBRI320_DETECT_GPIO 81
#define COLIBRI320_READY_GPIO 29
enum {
DETECT = 0,
READY = 1,
BVD1 = 2,
BVD2 = 3,
PPEN = 4,
RESET = 5,
};
/* Contents of this array are configured on-the-fly in init function */
static struct gpio colibri_pcmcia_gpios[] = {
{ 0, GPIOF_IN, "PCMCIA Detect" },
{ 0, GPIOF_IN, "PCMCIA Ready" },
{ 0, GPIOF_IN, "PCMCIA BVD1" },
{ 0, GPIOF_IN, "PCMCIA BVD2" },
{ 0, GPIOF_INIT_LOW, "PCMCIA PPEN" },
{ 0, GPIOF_INIT_HIGH,"PCMCIA Reset" },
};
static int colibri_pcmcia_hw_init(struct soc_pcmcia_socket *skt)
{
int ret;
ret = gpio_request_array(colibri_pcmcia_gpios,
ARRAY_SIZE(colibri_pcmcia_gpios));
if (ret)
goto err1;
skt->socket.pci_irq = gpio_to_irq(colibri_pcmcia_gpios[READY].gpio);
skt->stat[SOC_STAT_CD].irq = gpio_to_irq(colibri_pcmcia_gpios[DETECT].gpio);
skt->stat[SOC_STAT_CD].name = "PCMCIA CD";
err1:
return ret;
}
static void colibri_pcmcia_hw_shutdown(struct soc_pcmcia_socket *skt)
{
gpio_free_array(colibri_pcmcia_gpios,
ARRAY_SIZE(colibri_pcmcia_gpios));
}
static void colibri_pcmcia_socket_state(struct soc_pcmcia_socket *skt,
struct pcmcia_state *state)
{
state->detect = !!gpio_get_value(colibri_pcmcia_gpios[DETECT].gpio);
state->ready = !!gpio_get_value(colibri_pcmcia_gpios[READY].gpio);
state->bvd1 = !!gpio_get_value(colibri_pcmcia_gpios[BVD1].gpio);
state->bvd2 = !!gpio_get_value(colibri_pcmcia_gpios[BVD2].gpio);
state->vs_3v = 1;
state->vs_Xv = 0;
}
static int
colibri_pcmcia_configure_socket(struct soc_pcmcia_socket *skt,
const socket_state_t *state)
{
gpio_set_value(colibri_pcmcia_gpios[PPEN].gpio,
!(state->Vcc == 33 && state->Vpp < 50));
gpio_set_value(colibri_pcmcia_gpios[RESET].gpio,
state->flags & SS_RESET);
return 0;
}
static struct pcmcia_low_level colibri_pcmcia_ops = {
.owner = THIS_MODULE,
.first = 0,
.nr = 1,
.hw_init = colibri_pcmcia_hw_init,
.hw_shutdown = colibri_pcmcia_hw_shutdown,
.socket_state = colibri_pcmcia_socket_state,
.configure_socket = colibri_pcmcia_configure_socket,
};
static struct platform_device *colibri_pcmcia_device;
static int __init colibri_pcmcia_init(void)
{
int ret;
if (!machine_is_colibri() && !machine_is_colibri320())
return -ENODEV;
colibri_pcmcia_device = platform_device_alloc("pxa2xx-pcmcia", -1);
if (!colibri_pcmcia_device)
return -ENOMEM;
/* Colibri PXA270 */
if (machine_is_colibri()) {
colibri_pcmcia_gpios[RESET].gpio = COLIBRI270_RESET_GPIO;
colibri_pcmcia_gpios[PPEN].gpio = COLIBRI270_PPEN_GPIO;
colibri_pcmcia_gpios[BVD1].gpio = COLIBRI270_BVD1_GPIO;
colibri_pcmcia_gpios[BVD2].gpio = COLIBRI270_BVD2_GPIO;
colibri_pcmcia_gpios[DETECT].gpio = COLIBRI270_DETECT_GPIO;
colibri_pcmcia_gpios[READY].gpio = COLIBRI270_READY_GPIO;
/* Colibri PXA320 */
} else if (machine_is_colibri320()) {
colibri_pcmcia_gpios[RESET].gpio = COLIBRI320_RESET_GPIO;
colibri_pcmcia_gpios[PPEN].gpio = COLIBRI320_PPEN_GPIO;
colibri_pcmcia_gpios[BVD1].gpio = COLIBRI320_BVD1_GPIO;
colibri_pcmcia_gpios[BVD2].gpio = COLIBRI320_BVD2_GPIO;
colibri_pcmcia_gpios[DETECT].gpio = COLIBRI320_DETECT_GPIO;
colibri_pcmcia_gpios[READY].gpio = COLIBRI320_READY_GPIO;
}
ret = platform_device_add_data(colibri_pcmcia_device,
&colibri_pcmcia_ops, sizeof(colibri_pcmcia_ops));
if (!ret)
ret = platform_device_add(colibri_pcmcia_device);
if (ret)
platform_device_put(colibri_pcmcia_device);
return ret;
}
static void __exit colibri_pcmcia_exit(void)
{
platform_device_unregister(colibri_pcmcia_device);
}
module_init(colibri_pcmcia_init);
module_exit(colibri_pcmcia_exit);
MODULE_AUTHOR("Marek Vasut <marek.vasut@gmail.com>");
MODULE_DESCRIPTION("PCMCIA support for Toradex Colibri PXA270/PXA320");
MODULE_ALIAS("platform:pxa2xx-pcmcia");
MODULE_LICENSE("GPL");
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