xen-netback: switch to NAPI + kthread 1:1 model
This patch implements 1:1 model netback. NAPI and kthread are utilized
to do the weight-lifting job:
- NAPI is used for guest side TX (host side RX)
- kthread is used for guest side RX (host side TX)
Xenvif and xen_netbk are made into one structure to reduce code size.
This model provides better scheduling fairness among vifs. It is also
prerequisite for implementing multiqueue for Xen netback.
Signed-off-by: Wei Liu <[email protected]>
Acked-by: Ian Campbell <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 91f163d..44ccc67 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -70,116 +70,25 @@
*/
#define XEN_NETBK_LEGACY_SLOTS_MAX XEN_NETIF_NR_SLOTS_MIN
-typedef unsigned int pending_ring_idx_t;
-#define INVALID_PENDING_RING_IDX (~0U)
-
-struct pending_tx_info {
- struct xen_netif_tx_request req; /* coalesced tx request */
- struct xenvif *vif;
- pending_ring_idx_t head; /* head != INVALID_PENDING_RING_IDX
- * if it is head of one or more tx
- * reqs
- */
-};
-
-struct netbk_rx_meta {
- int id;
- int size;
- int gso_size;
-};
-
-#define MAX_PENDING_REQS 256
-
-/* Discriminate from any valid pending_idx value. */
-#define INVALID_PENDING_IDX 0xFFFF
-
-#define MAX_BUFFER_OFFSET PAGE_SIZE
-
-struct xen_netbk {
- wait_queue_head_t wq;
- struct task_struct *task;
-
- struct sk_buff_head rx_queue;
- struct sk_buff_head tx_queue;
-
- struct timer_list net_timer;
-
- struct page *mmap_pages[MAX_PENDING_REQS];
-
- pending_ring_idx_t pending_prod;
- pending_ring_idx_t pending_cons;
- struct list_head net_schedule_list;
-
- /* Protect the net_schedule_list in netif. */
- spinlock_t net_schedule_list_lock;
-
- atomic_t netfront_count;
-
- 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];
-
- u16 pending_ring[MAX_PENDING_REQS];
-
- /*
- * Given MAX_BUFFER_OFFSET of 4096 the worst case is that each
- * head/fragment page uses 2 copy operations because it
- * straddles two buffers in the frontend.
- */
- struct gnttab_copy grant_copy_op[2*XEN_NETIF_RX_RING_SIZE];
- struct netbk_rx_meta meta[2*XEN_NETIF_RX_RING_SIZE];
-};
-
-static struct xen_netbk *xen_netbk;
-static int xen_netbk_group_nr;
-
/*
* If head != INVALID_PENDING_RING_IDX, it means this tx request is head of
* one or more merged tx requests, otherwise it is the continuation of
* previous tx request.
*/
-static inline int pending_tx_is_head(struct xen_netbk *netbk, RING_IDX idx)
+static inline int pending_tx_is_head(struct xenvif *vif, RING_IDX idx)
{
- return netbk->pending_tx_info[idx].head != INVALID_PENDING_RING_IDX;
+ return vif->pending_tx_info[idx].head != INVALID_PENDING_RING_IDX;
}
-void xen_netbk_add_xenvif(struct xenvif *vif)
-{
- int i;
- int min_netfront_count;
- int min_group = 0;
- struct xen_netbk *netbk;
-
- min_netfront_count = atomic_read(&xen_netbk[0].netfront_count);
- for (i = 0; i < xen_netbk_group_nr; i++) {
- int netfront_count = atomic_read(&xen_netbk[i].netfront_count);
- if (netfront_count < min_netfront_count) {
- min_group = i;
- min_netfront_count = netfront_count;
- }
- }
-
- netbk = &xen_netbk[min_group];
-
- vif->netbk = netbk;
- atomic_inc(&netbk->netfront_count);
-}
-
-void xen_netbk_remove_xenvif(struct xenvif *vif)
-{
- struct xen_netbk *netbk = vif->netbk;
- vif->netbk = NULL;
- atomic_dec(&netbk->netfront_count);
-}
-
-static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
+static void xen_netbk_idx_release(struct xenvif *vif, u16 pending_idx,
u8 status);
static void make_tx_response(struct xenvif *vif,
struct xen_netif_tx_request *txp,
s8 st);
+
+static inline int tx_work_todo(struct xenvif *vif);
+static inline int rx_work_todo(struct xenvif *vif);
+
static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif,
u16 id,
s8 st,
@@ -187,16 +96,16 @@
u16 size,
u16 flags);
-static inline unsigned long idx_to_pfn(struct xen_netbk *netbk,
+static inline unsigned long idx_to_pfn(struct xenvif *vif,
u16 idx)
{
- return page_to_pfn(netbk->mmap_pages[idx]);
+ return page_to_pfn(vif->mmap_pages[idx]);
}
-static inline unsigned long idx_to_kaddr(struct xen_netbk *netbk,
+static inline unsigned long idx_to_kaddr(struct xenvif *vif,
u16 idx)
{
- return (unsigned long)pfn_to_kaddr(idx_to_pfn(netbk, idx));
+ return (unsigned long)pfn_to_kaddr(idx_to_pfn(vif, idx));
}
/*
@@ -224,15 +133,10 @@
return i & (MAX_PENDING_REQS-1);
}
-static inline pending_ring_idx_t nr_pending_reqs(struct xen_netbk *netbk)
+static inline pending_ring_idx_t nr_pending_reqs(struct xenvif *vif)
{
return MAX_PENDING_REQS -
- netbk->pending_prod + netbk->pending_cons;
-}
-
-static void xen_netbk_kick_thread(struct xen_netbk *netbk)
-{
- wake_up(&netbk->wq);
+ vif->pending_prod + vif->pending_cons;
}
static int max_required_rx_slots(struct xenvif *vif)
@@ -364,15 +268,15 @@
unsigned copy_prod, copy_cons;
unsigned meta_prod, meta_cons;
struct gnttab_copy *copy;
- struct netbk_rx_meta *meta;
+ struct xenvif_rx_meta *meta;
int copy_off;
grant_ref_t copy_gref;
};
-static struct netbk_rx_meta *get_next_rx_buffer(struct xenvif *vif,
- struct netrx_pending_operations *npo)
+static struct xenvif_rx_meta *get_next_rx_buffer(struct xenvif *vif,
+ struct netrx_pending_operations *npo)
{
- struct netbk_rx_meta *meta;
+ struct xenvif_rx_meta *meta;
struct xen_netif_rx_request *req;
req = RING_GET_REQUEST(&vif->rx, vif->rx.req_cons++);
@@ -398,7 +302,7 @@
unsigned long offset, int *head)
{
struct gnttab_copy *copy_gop;
- struct netbk_rx_meta *meta;
+ struct xenvif_rx_meta *meta;
unsigned long bytes;
/* Data must not cross a page boundary. */
@@ -434,15 +338,15 @@
copy_gop = npo->copy + npo->copy_prod++;
copy_gop->flags = GNTCOPY_dest_gref;
+ copy_gop->len = bytes;
+
copy_gop->source.domid = DOMID_SELF;
copy_gop->source.u.gmfn = virt_to_mfn(page_address(page));
-
copy_gop->source.offset = offset;
- copy_gop->dest.domid = vif->domid;
+ copy_gop->dest.domid = vif->domid;
copy_gop->dest.offset = npo->copy_off;
copy_gop->dest.u.ref = npo->copy_gref;
- copy_gop->len = bytes;
npo->copy_off += bytes;
meta->size += bytes;
@@ -485,7 +389,7 @@
int nr_frags = skb_shinfo(skb)->nr_frags;
int i;
struct xen_netif_rx_request *req;
- struct netbk_rx_meta *meta;
+ struct xenvif_rx_meta *meta;
unsigned char *data;
int head = 1;
int old_meta_prod;
@@ -565,7 +469,7 @@
}
static void netbk_add_frag_responses(struct xenvif *vif, int status,
- struct netbk_rx_meta *meta,
+ struct xenvif_rx_meta *meta,
int nr_meta_slots)
{
int i;
@@ -594,9 +498,13 @@
int meta_slots_used;
};
-static void xen_netbk_rx_action(struct xen_netbk *netbk)
+static void xen_netbk_kick_thread(struct xenvif *vif)
{
- struct xenvif *vif = NULL, *tmp;
+ wake_up(&vif->wq);
+}
+
+void xen_netbk_rx_action(struct xenvif *vif)
+{
s8 status;
u16 flags;
struct xen_netif_rx_response *resp;
@@ -608,17 +516,18 @@
int count;
unsigned long offset;
struct skb_cb_overlay *sco;
+ int need_to_notify = 0;
struct netrx_pending_operations npo = {
- .copy = netbk->grant_copy_op,
- .meta = netbk->meta,
+ .copy = vif->grant_copy_op,
+ .meta = vif->meta,
};
skb_queue_head_init(&rxq);
count = 0;
- while ((skb = skb_dequeue(&netbk->rx_queue)) != NULL) {
+ while ((skb = skb_dequeue(&vif->rx_queue)) != NULL) {
vif = netdev_priv(skb->dev);
nr_frags = skb_shinfo(skb)->nr_frags;
@@ -635,27 +544,27 @@
break;
}
- BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta));
+ BUG_ON(npo.meta_prod > ARRAY_SIZE(vif->meta));
if (!npo.copy_prod)
return;
- BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op));
- gnttab_batch_copy(netbk->grant_copy_op, npo.copy_prod);
+ BUG_ON(npo.copy_prod > ARRAY_SIZE(vif->grant_copy_op));
+ gnttab_batch_copy(vif->grant_copy_op, npo.copy_prod);
while ((skb = __skb_dequeue(&rxq)) != NULL) {
sco = (struct skb_cb_overlay *)skb->cb;
vif = netdev_priv(skb->dev);
- if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
+ if (vif->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
resp = RING_GET_RESPONSE(&vif->rx,
- vif->rx.rsp_prod_pvt++);
+ vif->rx.rsp_prod_pvt++);
resp->flags = XEN_NETRXF_gso_prefix | XEN_NETRXF_more_data;
- resp->offset = netbk->meta[npo.meta_cons].gso_size;
- resp->id = netbk->meta[npo.meta_cons].id;
+ resp->offset = vif->meta[npo.meta_cons].gso_size;
+ resp->id = vif->meta[npo.meta_cons].id;
resp->status = sco->meta_slots_used;
npo.meta_cons++;
@@ -680,12 +589,12 @@
flags |= XEN_NETRXF_data_validated;
offset = 0;
- resp = make_rx_response(vif, netbk->meta[npo.meta_cons].id,
+ resp = make_rx_response(vif, vif->meta[npo.meta_cons].id,
status, offset,
- netbk->meta[npo.meta_cons].size,
+ vif->meta[npo.meta_cons].size,
flags);
- if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
+ if (vif->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
struct xen_netif_extra_info *gso =
(struct xen_netif_extra_info *)
RING_GET_RESPONSE(&vif->rx,
@@ -693,7 +602,7 @@
resp->flags |= XEN_NETRXF_extra_info;
- gso->u.gso.size = netbk->meta[npo.meta_cons].gso_size;
+ gso->u.gso.size = vif->meta[npo.meta_cons].gso_size;
gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
gso->u.gso.pad = 0;
gso->u.gso.features = 0;
@@ -703,112 +612,33 @@
}
netbk_add_frag_responses(vif, status,
- netbk->meta + npo.meta_cons + 1,
+ vif->meta + npo.meta_cons + 1,
sco->meta_slots_used);
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
+ if (ret)
+ need_to_notify = 1;
+
xenvif_notify_tx_completion(vif);
- if (ret && list_empty(&vif->notify_list))
- list_add_tail(&vif->notify_list, ¬ify);
- else
- xenvif_put(vif);
npo.meta_cons += sco->meta_slots_used;
dev_kfree_skb(skb);
}
- list_for_each_entry_safe(vif, tmp, ¬ify, notify_list) {
+ if (need_to_notify)
notify_remote_via_irq(vif->rx_irq);
- list_del_init(&vif->notify_list);
- xenvif_put(vif);
- }
/* More work to do? */
- if (!skb_queue_empty(&netbk->rx_queue) &&
- !timer_pending(&netbk->net_timer))
- xen_netbk_kick_thread(netbk);
+ if (!skb_queue_empty(&vif->rx_queue))
+ xen_netbk_kick_thread(vif);
}
void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
{
- struct xen_netbk *netbk = vif->netbk;
+ skb_queue_tail(&vif->rx_queue, skb);
- skb_queue_tail(&netbk->rx_queue, skb);
-
- xen_netbk_kick_thread(netbk);
-}
-
-static void xen_netbk_alarm(unsigned long data)
-{
- struct xen_netbk *netbk = (struct xen_netbk *)data;
- xen_netbk_kick_thread(netbk);
-}
-
-static int __on_net_schedule_list(struct xenvif *vif)
-{
- return !list_empty(&vif->schedule_list);
-}
-
-/* Must be called with net_schedule_list_lock held */
-static void remove_from_net_schedule_list(struct xenvif *vif)
-{
- if (likely(__on_net_schedule_list(vif))) {
- list_del_init(&vif->schedule_list);
- xenvif_put(vif);
- }
-}
-
-static struct xenvif *poll_net_schedule_list(struct xen_netbk *netbk)
-{
- struct xenvif *vif = NULL;
-
- spin_lock_irq(&netbk->net_schedule_list_lock);
- if (list_empty(&netbk->net_schedule_list))
- goto out;
-
- vif = list_first_entry(&netbk->net_schedule_list,
- struct xenvif, schedule_list);
- if (!vif)
- goto out;
-
- xenvif_get(vif);
-
- remove_from_net_schedule_list(vif);
-out:
- spin_unlock_irq(&netbk->net_schedule_list_lock);
- return vif;
-}
-
-void xen_netbk_schedule_xenvif(struct xenvif *vif)
-{
- unsigned long flags;
- struct xen_netbk *netbk = vif->netbk;
-
- if (__on_net_schedule_list(vif))
- goto kick;
-
- spin_lock_irqsave(&netbk->net_schedule_list_lock, flags);
- if (!__on_net_schedule_list(vif) &&
- likely(xenvif_schedulable(vif))) {
- list_add_tail(&vif->schedule_list, &netbk->net_schedule_list);
- xenvif_get(vif);
- }
- spin_unlock_irqrestore(&netbk->net_schedule_list_lock, flags);
-
-kick:
- smp_mb();
- if ((nr_pending_reqs(netbk) < (MAX_PENDING_REQS/2)) &&
- !list_empty(&netbk->net_schedule_list))
- xen_netbk_kick_thread(netbk);
-}
-
-void xen_netbk_deschedule_xenvif(struct xenvif *vif)
-{
- struct xen_netbk *netbk = vif->netbk;
- spin_lock_irq(&netbk->net_schedule_list_lock);
- remove_from_net_schedule_list(vif);
- spin_unlock_irq(&netbk->net_schedule_list_lock);
+ xen_netbk_kick_thread(vif);
}
void xen_netbk_check_rx_xenvif(struct xenvif *vif)
@@ -818,7 +648,7 @@
RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, more_to_do);
if (more_to_do)
- xen_netbk_schedule_xenvif(vif);
+ napi_schedule(&vif->napi);
}
static void tx_add_credit(struct xenvif *vif)
@@ -860,15 +690,12 @@
txp = RING_GET_REQUEST(&vif->tx, cons++);
} while (1);
vif->tx.req_cons = cons;
- xen_netbk_check_rx_xenvif(vif);
- xenvif_put(vif);
}
static void netbk_fatal_tx_err(struct xenvif *vif)
{
netdev_err(vif->dev, "fatal error; disabling device\n");
xenvif_carrier_off(vif);
- xenvif_put(vif);
}
static int netbk_count_requests(struct xenvif *vif,
@@ -969,19 +796,20 @@
return slots;
}
-static struct page *xen_netbk_alloc_page(struct xen_netbk *netbk,
+static struct page *xen_netbk_alloc_page(struct xenvif *vif,
u16 pending_idx)
{
struct page *page;
- page = alloc_page(GFP_KERNEL|__GFP_COLD);
+
+ page = alloc_page(GFP_ATOMIC|__GFP_COLD);
if (!page)
return NULL;
- netbk->mmap_pages[pending_idx] = page;
+ vif->mmap_pages[pending_idx] = page;
+
return page;
}
-static struct gnttab_copy *xen_netbk_get_requests(struct xen_netbk *netbk,
- struct xenvif *vif,
+static struct gnttab_copy *xen_netbk_get_requests(struct xenvif *vif,
struct sk_buff *skb,
struct xen_netif_tx_request *txp,
struct gnttab_copy *gop)
@@ -1012,9 +840,9 @@
for (shinfo->nr_frags = slot = start; slot < nr_slots;
shinfo->nr_frags++) {
struct pending_tx_info *pending_tx_info =
- netbk->pending_tx_info;
+ vif->pending_tx_info;
- page = alloc_page(GFP_KERNEL|__GFP_COLD);
+ page = alloc_page(GFP_ATOMIC|__GFP_COLD);
if (!page)
goto err;
@@ -1049,21 +877,18 @@
gop->len = txp->size;
dst_offset += gop->len;
- index = pending_index(netbk->pending_cons++);
+ index = pending_index(vif->pending_cons++);
- pending_idx = netbk->pending_ring[index];
+ pending_idx = vif->pending_ring[index];
memcpy(&pending_tx_info[pending_idx].req, txp,
sizeof(*txp));
- xenvif_get(vif);
-
- pending_tx_info[pending_idx].vif = vif;
/* Poison these fields, corresponding
* fields for head tx req will be set
* to correct values after the loop.
*/
- netbk->mmap_pages[pending_idx] = (void *)(~0UL);
+ vif->mmap_pages[pending_idx] = (void *)(~0UL);
pending_tx_info[pending_idx].head =
INVALID_PENDING_RING_IDX;
@@ -1083,7 +908,7 @@
first->req.offset = 0;
first->req.size = dst_offset;
first->head = start_idx;
- netbk->mmap_pages[head_idx] = page;
+ vif->mmap_pages[head_idx] = page;
frag_set_pending_idx(&frags[shinfo->nr_frags], head_idx);
}
@@ -1093,18 +918,18 @@
err:
/* Unwind, freeing all pages and sending error responses. */
while (shinfo->nr_frags-- > start) {
- xen_netbk_idx_release(netbk,
+ xen_netbk_idx_release(vif,
frag_get_pending_idx(&frags[shinfo->nr_frags]),
XEN_NETIF_RSP_ERROR);
}
/* The head too, if necessary. */
if (start)
- xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+ xen_netbk_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
return NULL;
}
-static int xen_netbk_tx_check_gop(struct xen_netbk *netbk,
+static int xen_netbk_tx_check_gop(struct xenvif *vif,
struct sk_buff *skb,
struct gnttab_copy **gopp)
{
@@ -1119,7 +944,7 @@
/* Check status of header. */
err = gop->status;
if (unlikely(err))
- xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+ xen_netbk_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
/* Skip first skb fragment if it is on same page as header fragment. */
start = (frag_get_pending_idx(&shinfo->frags[0]) == pending_idx);
@@ -1129,7 +954,7 @@
pending_ring_idx_t head;
pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
- tx_info = &netbk->pending_tx_info[pending_idx];
+ tx_info = &vif->pending_tx_info[pending_idx];
head = tx_info->head;
/* Check error status: if okay then remember grant handle. */
@@ -1137,18 +962,19 @@
newerr = (++gop)->status;
if (newerr)
break;
- peek = netbk->pending_ring[pending_index(++head)];
- } while (!pending_tx_is_head(netbk, peek));
+ peek = vif->pending_ring[pending_index(++head)];
+ } while (!pending_tx_is_head(vif, peek));
if (likely(!newerr)) {
/* Had a previous error? Invalidate this fragment. */
if (unlikely(err))
- xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+ xen_netbk_idx_release(vif, pending_idx,
+ XEN_NETIF_RSP_OKAY);
continue;
}
/* Error on this fragment: respond to client with an error. */
- xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_ERROR);
+ xen_netbk_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
/* Not the first error? Preceding frags already invalidated. */
if (err)
@@ -1156,10 +982,11 @@
/* First error: invalidate header and preceding fragments. */
pending_idx = *((u16 *)skb->data);
- xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+ xen_netbk_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
for (j = start; j < i; j++) {
pending_idx = frag_get_pending_idx(&shinfo->frags[j]);
- xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+ xen_netbk_idx_release(vif, pending_idx,
+ XEN_NETIF_RSP_OKAY);
}
/* Remember the error: invalidate all subsequent fragments. */
@@ -1170,7 +997,7 @@
return err;
}
-static void xen_netbk_fill_frags(struct xen_netbk *netbk, struct sk_buff *skb)
+static void xen_netbk_fill_frags(struct xenvif *vif, struct sk_buff *skb)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
int nr_frags = shinfo->nr_frags;
@@ -1184,16 +1011,16 @@
pending_idx = frag_get_pending_idx(frag);
- txp = &netbk->pending_tx_info[pending_idx].req;
- page = virt_to_page(idx_to_kaddr(netbk, pending_idx));
+ txp = &vif->pending_tx_info[pending_idx].req;
+ page = virt_to_page(idx_to_kaddr(vif, pending_idx));
__skb_fill_page_desc(skb, i, page, txp->offset, txp->size);
skb->len += txp->size;
skb->data_len += txp->size;
skb->truesize += txp->size;
/* Take an extra reference to offset xen_netbk_idx_release */
- get_page(netbk->mmap_pages[pending_idx]);
- xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+ get_page(vif->mmap_pages[pending_idx]);
+ xen_netbk_idx_release(vif, pending_idx, XEN_NETIF_RSP_OKAY);
}
}
@@ -1353,16 +1180,14 @@
return false;
}
-static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
+static unsigned xen_netbk_tx_build_gops(struct xenvif *vif)
{
- struct gnttab_copy *gop = netbk->tx_copy_ops, *request_gop;
+ struct gnttab_copy *gop = vif->tx_copy_ops, *request_gop;
struct sk_buff *skb;
int ret;
- while ((nr_pending_reqs(netbk) + XEN_NETBK_LEGACY_SLOTS_MAX
- < MAX_PENDING_REQS) &&
- !list_empty(&netbk->net_schedule_list)) {
- struct xenvif *vif;
+ while ((nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
+ < MAX_PENDING_REQS)) {
struct xen_netif_tx_request txreq;
struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
struct page *page;
@@ -1373,16 +1198,6 @@
unsigned int data_len;
pending_ring_idx_t index;
- /* Get a netif from the list with work to do. */
- vif = poll_net_schedule_list(netbk);
- /* This can sometimes happen because the test of
- * list_empty(net_schedule_list) at the top of the
- * loop is unlocked. Just go back and have another
- * look.
- */
- if (!vif)
- continue;
-
if (vif->tx.sring->req_prod - vif->tx.req_cons >
XEN_NETIF_TX_RING_SIZE) {
netdev_err(vif->dev,
@@ -1395,10 +1210,8 @@
}
RING_FINAL_CHECK_FOR_REQUESTS(&vif->tx, work_to_do);
- if (!work_to_do) {
- xenvif_put(vif);
- continue;
- }
+ if (!work_to_do)
+ break;
idx = vif->tx.req_cons;
rmb(); /* Ensure that we see the request before we copy it. */
@@ -1406,10 +1219,8 @@
/* Credit-based scheduling. */
if (txreq.size > vif->remaining_credit &&
- tx_credit_exceeded(vif, txreq.size)) {
- xenvif_put(vif);
- continue;
- }
+ tx_credit_exceeded(vif, txreq.size))
+ break;
vif->remaining_credit -= txreq.size;
@@ -1422,12 +1233,12 @@
work_to_do);
idx = vif->tx.req_cons;
if (unlikely(work_to_do < 0))
- continue;
+ break;
}
ret = netbk_count_requests(vif, &txreq, txfrags, work_to_do);
if (unlikely(ret < 0))
- continue;
+ break;
idx += ret;
@@ -1435,7 +1246,7 @@
netdev_dbg(vif->dev,
"Bad packet size: %d\n", txreq.size);
netbk_tx_err(vif, &txreq, idx);
- continue;
+ break;
}
/* No crossing a page as the payload mustn't fragment. */
@@ -1445,11 +1256,11 @@
txreq.offset, txreq.size,
(txreq.offset&~PAGE_MASK) + txreq.size);
netbk_fatal_tx_err(vif);
- continue;
+ break;
}
- index = pending_index(netbk->pending_cons);
- pending_idx = netbk->pending_ring[index];
+ index = pending_index(vif->pending_cons);
+ pending_idx = vif->pending_ring[index];
data_len = (txreq.size > PKT_PROT_LEN &&
ret < XEN_NETBK_LEGACY_SLOTS_MAX) ?
@@ -1474,16 +1285,16 @@
if (netbk_set_skb_gso(vif, skb, gso)) {
/* Failure in netbk_set_skb_gso is fatal. */
kfree_skb(skb);
- continue;
+ break;
}
}
/* XXX could copy straight to head */
- page = xen_netbk_alloc_page(netbk, pending_idx);
+ page = xen_netbk_alloc_page(vif, pending_idx);
if (!page) {
kfree_skb(skb);
netbk_tx_err(vif, &txreq, idx);
- continue;
+ break;
}
gop->source.u.ref = txreq.gref;
@@ -1499,10 +1310,9 @@
gop++;
- memcpy(&netbk->pending_tx_info[pending_idx].req,
+ memcpy(&vif->pending_tx_info[pending_idx].req,
&txreq, sizeof(txreq));
- netbk->pending_tx_info[pending_idx].vif = vif;
- netbk->pending_tx_info[pending_idx].head = index;
+ vif->pending_tx_info[pending_idx].head = index;
*((u16 *)skb->data) = pending_idx;
__skb_put(skb, data_len);
@@ -1517,46 +1327,45 @@
INVALID_PENDING_IDX);
}
- netbk->pending_cons++;
+ vif->pending_cons++;
- request_gop = xen_netbk_get_requests(netbk, vif,
- skb, txfrags, gop);
+ request_gop = xen_netbk_get_requests(vif, skb, txfrags, gop);
if (request_gop == NULL) {
kfree_skb(skb);
netbk_tx_err(vif, &txreq, idx);
- continue;
+ break;
}
gop = request_gop;
- __skb_queue_tail(&netbk->tx_queue, skb);
+ __skb_queue_tail(&vif->tx_queue, skb);
vif->tx.req_cons = idx;
- xen_netbk_check_rx_xenvif(vif);
- if ((gop-netbk->tx_copy_ops) >= ARRAY_SIZE(netbk->tx_copy_ops))
+ if ((gop-vif->tx_copy_ops) >= ARRAY_SIZE(vif->tx_copy_ops))
break;
}
- return gop - netbk->tx_copy_ops;
+ return gop - vif->tx_copy_ops;
}
-static void xen_netbk_tx_submit(struct xen_netbk *netbk)
-{
- struct gnttab_copy *gop = netbk->tx_copy_ops;
- struct sk_buff *skb;
- while ((skb = __skb_dequeue(&netbk->tx_queue)) != NULL) {
+static int xen_netbk_tx_submit(struct xenvif *vif, int budget)
+{
+ struct gnttab_copy *gop = vif->tx_copy_ops;
+ struct sk_buff *skb;
+ int work_done = 0;
+
+ while (work_done < budget &&
+ (skb = __skb_dequeue(&vif->tx_queue)) != NULL) {
struct xen_netif_tx_request *txp;
- struct xenvif *vif;
u16 pending_idx;
unsigned data_len;
pending_idx = *((u16 *)skb->data);
- vif = netbk->pending_tx_info[pending_idx].vif;
- txp = &netbk->pending_tx_info[pending_idx].req;
+ txp = &vif->pending_tx_info[pending_idx].req;
/* Check the remap error code. */
- if (unlikely(xen_netbk_tx_check_gop(netbk, skb, &gop))) {
+ if (unlikely(xen_netbk_tx_check_gop(vif, skb, &gop))) {
netdev_dbg(vif->dev, "netback grant failed.\n");
skb_shinfo(skb)->nr_frags = 0;
kfree_skb(skb);
@@ -1565,7 +1374,7 @@
data_len = skb->len;
memcpy(skb->data,
- (void *)(idx_to_kaddr(netbk, pending_idx)|txp->offset),
+ (void *)(idx_to_kaddr(vif, pending_idx)|txp->offset),
data_len);
if (data_len < txp->size) {
/* Append the packet payload as a fragment. */
@@ -1573,7 +1382,8 @@
txp->size -= data_len;
} else {
/* Schedule a response immediately. */
- xen_netbk_idx_release(netbk, pending_idx, XEN_NETIF_RSP_OKAY);
+ xen_netbk_idx_release(vif, pending_idx,
+ XEN_NETIF_RSP_OKAY);
}
if (txp->flags & XEN_NETTXF_csum_blank)
@@ -1581,7 +1391,7 @@
else if (txp->flags & XEN_NETTXF_data_validated)
skb->ip_summed = CHECKSUM_UNNECESSARY;
- xen_netbk_fill_frags(netbk, skb);
+ xen_netbk_fill_frags(vif, skb);
/*
* If the initial fragment was < PKT_PROT_LEN then
@@ -1609,53 +1419,61 @@
vif->dev->stats.rx_bytes += skb->len;
vif->dev->stats.rx_packets++;
- xenvif_receive_skb(vif, skb);
+ work_done++;
+
+ netif_receive_skb(skb);
}
+
+ return work_done;
}
/* Called after netfront has transmitted */
-static void xen_netbk_tx_action(struct xen_netbk *netbk)
+int xen_netbk_tx_action(struct xenvif *vif, int budget)
{
unsigned nr_gops;
+ int work_done;
- nr_gops = xen_netbk_tx_build_gops(netbk);
+ if (unlikely(!tx_work_todo(vif)))
+ return 0;
+
+ nr_gops = xen_netbk_tx_build_gops(vif);
if (nr_gops == 0)
- return;
+ return 0;
- gnttab_batch_copy(netbk->tx_copy_ops, nr_gops);
+ gnttab_batch_copy(vif->tx_copy_ops, nr_gops);
- xen_netbk_tx_submit(netbk);
+ work_done = xen_netbk_tx_submit(vif, nr_gops);
+
+ return work_done;
}
-static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx,
+static void xen_netbk_idx_release(struct xenvif *vif, u16 pending_idx,
u8 status)
{
- struct xenvif *vif;
struct pending_tx_info *pending_tx_info;
pending_ring_idx_t head;
u16 peek; /* peek into next tx request */
- BUG_ON(netbk->mmap_pages[pending_idx] == (void *)(~0UL));
+ BUG_ON(vif->mmap_pages[pending_idx] == (void *)(~0UL));
/* Already complete? */
- if (netbk->mmap_pages[pending_idx] == NULL)
+ if (vif->mmap_pages[pending_idx] == NULL)
return;
- pending_tx_info = &netbk->pending_tx_info[pending_idx];
+ pending_tx_info = &vif->pending_tx_info[pending_idx];
- vif = pending_tx_info->vif;
head = pending_tx_info->head;
- BUG_ON(!pending_tx_is_head(netbk, head));
- BUG_ON(netbk->pending_ring[pending_index(head)] != pending_idx);
+ BUG_ON(!pending_tx_is_head(vif, head));
+ BUG_ON(vif->pending_ring[pending_index(head)] != pending_idx);
do {
pending_ring_idx_t index;
pending_ring_idx_t idx = pending_index(head);
- u16 info_idx = netbk->pending_ring[idx];
+ u16 info_idx = vif->pending_ring[idx];
- pending_tx_info = &netbk->pending_tx_info[info_idx];
+ pending_tx_info = &vif->pending_tx_info[info_idx];
make_tx_response(vif, &pending_tx_info->req, status);
/* Setting any number other than
@@ -1664,18 +1482,15 @@
*/
pending_tx_info->head = 0;
- index = pending_index(netbk->pending_prod++);
- netbk->pending_ring[index] = netbk->pending_ring[info_idx];
+ index = pending_index(vif->pending_prod++);
+ vif->pending_ring[index] = vif->pending_ring[info_idx];
- xenvif_put(vif);
+ peek = vif->pending_ring[pending_index(++head)];
- peek = netbk->pending_ring[pending_index(++head)];
+ } while (!pending_tx_is_head(vif, peek));
- } while (!pending_tx_is_head(netbk, peek));
-
- netbk->mmap_pages[pending_idx]->mapping = 0;
- put_page(netbk->mmap_pages[pending_idx]);
- netbk->mmap_pages[pending_idx] = NULL;
+ put_page(vif->mmap_pages[pending_idx]);
+ vif->mmap_pages[pending_idx] = NULL;
}
@@ -1723,45 +1538,22 @@
return resp;
}
-static inline int rx_work_todo(struct xen_netbk *netbk)
+static inline int rx_work_todo(struct xenvif *vif)
{
- return !skb_queue_empty(&netbk->rx_queue);
+ return !skb_queue_empty(&vif->rx_queue);
}
-static inline int tx_work_todo(struct xen_netbk *netbk)
+static inline int tx_work_todo(struct xenvif *vif)
{
- if ((nr_pending_reqs(netbk) + XEN_NETBK_LEGACY_SLOTS_MAX
- < MAX_PENDING_REQS) &&
- !list_empty(&netbk->net_schedule_list))
+ if (likely(RING_HAS_UNCONSUMED_REQUESTS(&vif->tx)) &&
+ (nr_pending_reqs(vif) + XEN_NETBK_LEGACY_SLOTS_MAX
+ < MAX_PENDING_REQS))
return 1;
return 0;
}
-static int xen_netbk_kthread(void *data)
-{
- struct xen_netbk *netbk = data;
- while (!kthread_should_stop()) {
- wait_event_interruptible(netbk->wq,
- rx_work_todo(netbk) ||
- tx_work_todo(netbk) ||
- kthread_should_stop());
- cond_resched();
-
- if (kthread_should_stop())
- break;
-
- if (rx_work_todo(netbk))
- xen_netbk_rx_action(netbk);
-
- if (tx_work_todo(netbk))
- xen_netbk_tx_action(netbk);
- }
-
- return 0;
-}
-
void xen_netbk_unmap_frontend_rings(struct xenvif *vif)
{
if (vif->tx.sring)
@@ -1807,11 +1599,29 @@
return err;
}
+int xen_netbk_kthread(void *data)
+{
+ struct xenvif *vif = data;
+
+ while (!kthread_should_stop()) {
+ wait_event_interruptible(vif->wq,
+ rx_work_todo(vif) ||
+ kthread_should_stop());
+ if (kthread_should_stop())
+ break;
+
+ if (rx_work_todo(vif))
+ xen_netbk_rx_action(vif);
+
+ cond_resched();
+ }
+
+ return 0;
+}
+
static int __init netback_init(void)
{
- int i;
int rc = 0;
- int group;
if (!xen_domain())
return -ENODEV;
@@ -1822,48 +1632,6 @@
fatal_skb_slots = XEN_NETBK_LEGACY_SLOTS_MAX;
}
- xen_netbk_group_nr = num_online_cpus();
- xen_netbk = vzalloc(sizeof(struct xen_netbk) * xen_netbk_group_nr);
- if (!xen_netbk)
- return -ENOMEM;
-
- for (group = 0; group < xen_netbk_group_nr; group++) {
- struct xen_netbk *netbk = &xen_netbk[group];
- skb_queue_head_init(&netbk->rx_queue);
- skb_queue_head_init(&netbk->tx_queue);
-
- init_timer(&netbk->net_timer);
- netbk->net_timer.data = (unsigned long)netbk;
- netbk->net_timer.function = xen_netbk_alarm;
-
- netbk->pending_cons = 0;
- netbk->pending_prod = MAX_PENDING_REQS;
- for (i = 0; i < MAX_PENDING_REQS; i++)
- netbk->pending_ring[i] = i;
-
- init_waitqueue_head(&netbk->wq);
- netbk->task = kthread_create(xen_netbk_kthread,
- (void *)netbk,
- "netback/%u", group);
-
- if (IS_ERR(netbk->task)) {
- pr_alert("kthread_create() fails at netback\n");
- del_timer(&netbk->net_timer);
- rc = PTR_ERR(netbk->task);
- goto failed_init;
- }
-
- kthread_bind(netbk->task, group);
-
- INIT_LIST_HEAD(&netbk->net_schedule_list);
-
- spin_lock_init(&netbk->net_schedule_list_lock);
-
- atomic_set(&netbk->netfront_count, 0);
-
- wake_up_process(netbk->task);
- }
-
rc = xenvif_xenbus_init();
if (rc)
goto failed_init;
@@ -1871,35 +1639,14 @@
return 0;
failed_init:
- while (--group >= 0) {
- struct xen_netbk *netbk = &xen_netbk[group];
- del_timer(&netbk->net_timer);
- kthread_stop(netbk->task);
- }
- vfree(xen_netbk);
return rc;
-
}
module_init(netback_init);
static void __exit netback_fini(void)
{
- int i, j;
-
xenvif_xenbus_fini();
-
- for (i = 0; i < xen_netbk_group_nr; i++) {
- struct xen_netbk *netbk = &xen_netbk[i];
- del_timer_sync(&netbk->net_timer);
- kthread_stop(netbk->task);
- for (j = 0; j < MAX_PENDING_REQS; j++) {
- if (netbk->mmap_pages[j])
- __free_page(netbk->mmap_pages[j]);
- }
- }
-
- vfree(xen_netbk);
}
module_exit(netback_fini);
