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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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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
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version 2
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* as published by the Free Software Foundation; or, when distributed
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* separately from the Linux kernel or incorporated into other
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* software packages, subject to the following license:
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this source file (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy, modify,
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* merge, publish, distribute, sublicense, and/or sell copies of the Software,
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* and to permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#ifndef __XEN_NETBACK__COMMON_H__
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#define __XEN_NETBACK__COMMON_H__
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#define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
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#include <linux/module.h>
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#include <linux/interrupt.h>
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#include <linux/slab.h>
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#include <linux/ip.h>
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#include <linux/in.h>
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#include <linux/io.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/wait.h>
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#include <linux/sched.h>
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#include <xen/interface/io/netif.h>
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#include <xen/interface/grant_table.h>
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#include <xen/grant_table.h>
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#include <xen/xenbus.h>
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typedef unsigned int pending_ring_idx_t;
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#define INVALID_PENDING_RING_IDX (~0U)
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/* For the head field in pending_tx_info: it is used to indicate
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* whether this tx info is the head of one or more coalesced requests.
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*
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* When head != INVALID_PENDING_RING_IDX, it means the start of a new
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* tx requests queue and the end of previous queue.
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*
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* An example sequence of head fields (I = INVALID_PENDING_RING_IDX):
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*
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* ...|0 I I I|5 I|9 I I I|...
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* -->|<-INUSE----------------
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*
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* After consuming the first slot(s) we have:
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*
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* ...|V V V V|5 I|9 I I I|...
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* -----FREE->|<-INUSE--------
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*
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* where V stands for "valid pending ring index". Any number other
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* than INVALID_PENDING_RING_IDX is OK. These entries are considered
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* free and can contain any number other than
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* INVALID_PENDING_RING_IDX. In practice we use 0.
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*
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* The in use non-INVALID_PENDING_RING_IDX (say 0, 5 and 9 in the
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* above example) number is the index into pending_tx_info and
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* mmap_pages arrays.
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*/
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struct pending_tx_info {
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struct xen_netif_tx_request req; /* coalesced tx request */
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pending_ring_idx_t head; /* head != INVALID_PENDING_RING_IDX
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* if it is head of one or more tx
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* reqs
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*/
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};
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#define XEN_NETIF_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
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#define XEN_NETIF_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
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struct xenvif_rx_meta {
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int id;
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int size;
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int gso_type;
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int gso_size;
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};
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#define GSO_BIT(type) \
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(1 << XEN_NETIF_GSO_TYPE_ ## type)
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/* Discriminate from any valid pending_idx value. */
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#define INVALID_PENDING_IDX 0xFFFF
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#define MAX_BUFFER_OFFSET PAGE_SIZE
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#define MAX_PENDING_REQS 256
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/* It's possible for an skb to have a maximal number of frags
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* but still be less than MAX_BUFFER_OFFSET in size. Thus the
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* worst-case number of copy operations is MAX_SKB_FRAGS per
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* ring slot.
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*/
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#define MAX_GRANT_COPY_OPS (MAX_SKB_FRAGS * XEN_NETIF_RX_RING_SIZE)
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struct xenvif {
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/* Unique identifier for this interface. */
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domid_t domid;
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unsigned int handle;
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/* Use NAPI for guest TX */
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struct napi_struct napi;
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/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
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unsigned int tx_irq;
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/* Only used when feature-split-event-channels = 1 */
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char tx_irq_name[IFNAMSIZ+4]; /* DEVNAME-tx */
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struct xen_netif_tx_back_ring tx;
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struct sk_buff_head tx_queue;
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struct page *mmap_pages[MAX_PENDING_REQS];
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pending_ring_idx_t pending_prod;
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pending_ring_idx_t pending_cons;
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u16 pending_ring[MAX_PENDING_REQS];
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struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
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/* Coalescing tx requests before copying makes number of grant
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* copy ops greater or equal to number of slots required. In
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* worst case a tx request consumes 2 gnttab_copy.
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*/
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struct gnttab_copy tx_copy_ops[2*MAX_PENDING_REQS];
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/* Use kthread for guest RX */
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struct task_struct *task;
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wait_queue_head_t wq;
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/* When feature-split-event-channels = 0, tx_irq = rx_irq. */
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unsigned int rx_irq;
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/* Only used when feature-split-event-channels = 1 */
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char rx_irq_name[IFNAMSIZ+4]; /* DEVNAME-rx */
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struct xen_netif_rx_back_ring rx;
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struct sk_buff_head rx_queue;
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RING_IDX rx_last_skb_slots;
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/* This array is allocated seperately as it is large */
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struct gnttab_copy *grant_copy_op;
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/* We create one meta structure per ring request we consume, so
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* the maximum number is the same as the ring size.
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*/
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struct xenvif_rx_meta meta[XEN_NETIF_RX_RING_SIZE];
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u8 fe_dev_addr[6];
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/* Frontend feature information. */
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int gso_mask;
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int gso_prefix_mask;
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u8 can_sg:1;
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u8 ip_csum:1;
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u8 ipv6_csum:1;
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/* Internal feature information. */
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u8 can_queue:1; /* can queue packets for receiver? */
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/* Transmit shaping: allow 'credit_bytes' every 'credit_usec'. */
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unsigned long credit_bytes;
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unsigned long credit_usec;
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unsigned long remaining_credit;
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struct timer_list credit_timeout;
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u64 credit_window_start;
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/* Statistics */
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unsigned long rx_gso_checksum_fixup;
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/* Miscellaneous private stuff. */
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struct net_device *dev;
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};
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static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif)
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{
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return to_xenbus_device(vif->dev->dev.parent);
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}
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struct xenvif *xenvif_alloc(struct device *parent,
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domid_t domid,
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unsigned int handle);
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int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref,
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unsigned long rx_ring_ref, unsigned int tx_evtchn,
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unsigned int rx_evtchn);
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void xenvif_disconnect(struct xenvif *vif);
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void xenvif_free(struct xenvif *vif);
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int xenvif_xenbus_init(void);
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void xenvif_xenbus_fini(void);
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int xenvif_schedulable(struct xenvif *vif);
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int xenvif_must_stop_queue(struct xenvif *vif);
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/* (Un)Map communication rings. */
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void xenvif_unmap_frontend_rings(struct xenvif *vif);
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int xenvif_map_frontend_rings(struct xenvif *vif,
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grant_ref_t tx_ring_ref,
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grant_ref_t rx_ring_ref);
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/* Check for SKBs from frontend and schedule backend processing */
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void xenvif_check_rx_xenvif(struct xenvif *vif);
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/* Prevent the device from generating any further traffic. */
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void xenvif_carrier_off(struct xenvif *vif);
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int xenvif_tx_action(struct xenvif *vif, int budget);
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int xenvif_kthread(void *data);
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void xenvif_kick_thread(struct xenvif *vif);
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/* Determine whether the needed number of slots (req) are available,
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* and set req_event if not.
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*/
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bool xenvif_rx_ring_slots_available(struct xenvif *vif, int needed);
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void xenvif_stop_queue(struct xenvif *vif);
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extern bool separate_tx_rx_irq;
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#endif /* __XEN_NETBACK__COMMON_H__ */
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