mirror of
https://github.com/torvalds/linux.git
synced 2024-12-28 05:41:55 +00:00
9ab9831b4c
The recent patch to fix receive side flow control
(11b57f9025: xen-netback: stop vif thread
spinning if frontend is unresponsive) solved the spinning thread problem,
however caused an another one. The receive side can stall, if:
- [THREAD] xenvif_rx_action sets rx_queue_stopped to true
- [INTERRUPT] interrupt happens, and sets rx_event to true
- [THREAD] then xenvif_kthread sets rx_event to false
- [THREAD] rx_work_todo doesn't return true anymore
Also, if interrupt sent but there is still no room in the ring, it take quite a
long time until xenvif_rx_action realize it. This patch ditch that two variable,
and rework rx_work_todo. If the thread finds it can't fit more skb's into the
ring, it saves the last slot estimation into rx_last_skb_slots, otherwise it's
kept as 0. Then rx_work_todo will check if:
- there is something to send to the ring (like before)
- there is space for the topmost packet in the queue
I think that's more natural and optimal thing to test than two bool which are
set somewhere else.
Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
Reviewed-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
232 lines
7.2 KiB
C
232 lines
7.2 KiB
C
/*
|
|
* 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; or, when distributed
|
|
* separately from the Linux kernel or incorporated into other
|
|
* software packages, subject to the following license:
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this source file (the "Software"), to deal in the Software without
|
|
* restriction, including without limitation the rights to use, copy, modify,
|
|
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
|
|
* and to permit persons to whom the Software is furnished to do so, subject to
|
|
* the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
|
|
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
|
|
* IN THE SOFTWARE.
|
|
*/
|
|
|
|
#ifndef __XEN_NETBACK__COMMON_H__
|
|
#define __XEN_NETBACK__COMMON_H__
|
|
|
|
#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/ip.h>
|
|
#include <linux/in.h>
|
|
#include <linux/io.h>
|
|
#include <linux/netdevice.h>
|
|
#include <linux/etherdevice.h>
|
|
#include <linux/wait.h>
|
|
#include <linux/sched.h>
|
|
|
|
#include <xen/interface/io/netif.h>
|
|
#include <xen/interface/grant_table.h>
|
|
#include <xen/grant_table.h>
|
|
#include <xen/xenbus.h>
|
|
|
|
typedef unsigned int pending_ring_idx_t;
|
|
#define INVALID_PENDING_RING_IDX (~0U)
|
|
|
|
/* For the head field in pending_tx_info: it is used to indicate
|
|
* whether this tx info is the head of one or more coalesced requests.
|
|
*
|
|
* When head != INVALID_PENDING_RING_IDX, it means the start of a new
|
|
* tx requests queue and the end of previous queue.
|
|
*
|
|
* An example sequence of head fields (I = INVALID_PENDING_RING_IDX):
|
|
*
|
|
* ...|0 I I I|5 I|9 I I I|...
|
|
* -->|<-INUSE----------------
|
|
*
|
|
* After consuming the first slot(s) we have:
|
|
*
|
|
* ...|V V V V|5 I|9 I I I|...
|
|
* -----FREE->|<-INUSE--------
|
|
*
|
|
* where V stands for "valid pending ring index". Any number other
|
|
* than INVALID_PENDING_RING_IDX is OK. These entries are considered
|
|
* free and can contain any number other than
|
|
* INVALID_PENDING_RING_IDX. In practice we use 0.
|
|
*
|
|
* The in use non-INVALID_PENDING_RING_IDX (say 0, 5 and 9 in the
|
|
* above example) number is the index into pending_tx_info and
|
|
* mmap_pages arrays.
|
|
*/
|
|
struct pending_tx_info {
|
|
struct xen_netif_tx_request req; /* coalesced tx request */
|
|
pending_ring_idx_t head; /* head != INVALID_PENDING_RING_IDX
|
|
* if it is head of one or more tx
|
|
* reqs
|
|
*/
|
|
};
|
|
|
|
#define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
|
|
#define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
|
|
|
|
struct xenvif_rx_meta {
|
|
int id;
|
|
int size;
|
|
int gso_type;
|
|
int gso_size;
|
|
};
|
|
|
|
#define GSO_BIT(type) \
|
|
(1 << XEN_NETIF_GSO_TYPE_ ## type)
|
|
|
|
/* Discriminate from any valid pending_idx value. */
|
|
#define INVALID_PENDING_IDX 0xFFFF
|
|
|
|
#define MAX_BUFFER_OFFSET PAGE_SIZE
|
|
|
|
#define MAX_PENDING_REQS 256
|
|
|
|
/* It's possible for an skb to have a maximal number of frags
|
|
* but still be less than MAX_BUFFER_OFFSET in size. Thus the
|
|
* worst-case number of copy operations is MAX_SKB_FRAGS per
|
|
* ring slot.
|
|
*/
|
|
#define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)
|
|
|
|
struct xenvif {
|
|
/* Unique identifier for this interface. */
|
|
domid_t domid;
|
|
unsigned int handle;
|
|
|
|
/* Use NAPI for guest TX */
|
|
struct napi_struct napi;
|
|
/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
|
|
unsigned int tx_irq;
|
|
/* Only used when feature-split-event-channels = 1 */
|
|
char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
|
|
struct xen_netif_tx_back_ring tx;
|
|
struct sk_buff_head tx_queue;
|
|
struct page *mmap_pages[MAX_PENDING_REQS];
|
|
pending_ring_idx_t pending_prod;
|
|
pending_ring_idx_t pending_cons;
|
|
u16 pending_ring[MAX_PENDING_REQS];
|
|
struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
|
|
|
|
/* Coalescing tx requests before copying makes number of grant
|
|
* copy ops greater or equal to number of slots required. In
|
|
* worst case a tx request consumes 2 gnttab_copy.
|
|
*/
|
|
struct gnttab_copy tx_copy_ops[2*MAX_PENDING_REQS];
|
|
|
|
|
|
/* Use kthread for guest RX */
|
|
struct task_struct *task;
|
|
wait_queue_head_t wq;
|
|
/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
|
|
unsigned int rx_irq;
|
|
/* Only used when feature-split-event-channels = 1 */
|
|
char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
|
|
struct xen_netif_rx_back_ring rx;
|
|
struct sk_buff_head rx_queue;
|
|
RING_IDX rx_last_skb_slots;
|
|
|
|
/* This array is allocated seperately as it is large */
|
|
struct gnttab_copy *grant_copy_op;
|
|
|
|
/* We create one meta structure per ring request we consume, so
|
|
* the maximum number is the same as the ring size.
|
|
*/
|
|
struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
|
|
|
|
u8 fe_dev_addr[6];
|
|
|
|
/* Frontend feature information. */
|
|
int gso_mask;
|
|
int gso_prefix_mask;
|
|
|
|
u8 can_sg:1;
|
|
u8 ip_csum:1;
|
|
u8 ipv6_csum:1;
|
|
|
|
/* Internal feature information. */
|
|
u8 can_queue:1; /* can queue packets for receiver? */
|
|
|
|
/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
|
|
unsigned long credit_bytes;
|
|
unsigned long credit_usec;
|
|
unsigned long remaining_credit;
|
|
struct timer_list credit_timeout;
|
|
u64 credit_window_start;
|
|
|
|
/* Statistics */
|
|
unsigned long rx_gso_checksum_fixup;
|
|
|
|
/* Miscellaneous private stuff. */
|
|
struct net_device *dev;
|
|
};
|
|
|
|
static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
|
|
{
|
|
return to_xenbus_device(vif->dev->dev.parent);
|
|
}
|
|
|
|
struct xenvif *xenvif_alloc(struct device *parent,
|
|
domid_t domid,
|
|
unsigned int handle);
|
|
|
|
int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
|
|
unsigned long rx_ring_ref, unsigned int tx_evtchn,
|
|
unsigned int rx_evtchn);
|
|
void xenvif_disconnect(struct xenvif *vif);
|
|
void xenvif_free(struct xenvif *vif);
|
|
|
|
int xenvif_xenbus_init(void);
|
|
void xenvif_xenbus_fini(void);
|
|
|
|
int xenvif_schedulable(struct xenvif *vif);
|
|
|
|
int xenvif_must_stop_queue(struct xenvif *vif);
|
|
|
|
/* (Un)Map communication rings. */
|
|
void xenvif_unmap_frontend_rings(struct xenvif *vif);
|
|
int xenvif_map_frontend_rings(struct xenvif *vif,
|
|
grant_ref_t tx_ring_ref,
|
|
grant_ref_t rx_ring_ref);
|
|
|
|
/* Check for SKBs from frontend and schedule backend processing */
|
|
void xenvif_check_rx_xenvif(struct xenvif *vif);
|
|
|
|
/* Prevent the device from generating any further traffic. */
|
|
void xenvif_carrier_off(struct xenvif *vif);
|
|
|
|
int xenvif_tx_action(struct xenvif *vif, int budget);
|
|
|
|
int xenvif_kthread(void *data);
|
|
void xenvif_kick_thread(struct xenvif *vif);
|
|
|
|
/* Determine whether the needed number of slots (req) are available,
|
|
* and set req_event if not.
|
|
*/
|
|
bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed);
|
|
|
|
void xenvif_stop_queue(struct xenvif *vif);
|
|
|
|
extern bool separate_tx_rx_irq;
|
|
|
|
#endif /* __XEN_NETBACK__COMMON_H__ */
|