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Re: [Xen-devel] [PATCH 6/8] netfront: multi-page ring support
On 2013-2-16 0:00, Wei Liu wrote:
Signed-off-by: Wei Liu<wei.liu2@xxxxxxxxxx>
---
drivers/net/xen-netfront.c | 246 +++++++++++++++++++++++++++++++-------------
1 file changed, 174 insertions(+), 72 deletions(-)
diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 8bd75a1..de73a71 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -67,9 +67,19 @@ struct netfront_cb {
#define GRANT_INVALID_REF 0
-#define NET_TX_RING_SIZE __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE)
-#define NET_RX_RING_SIZE __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE)
-#define TX_MAX_TARGET min_t(int, NET_TX_RING_SIZE, 256)
+#define XENNET_MAX_RING_PAGE_ORDER XENBUS_MAX_RING_PAGE_ORDER
+#define XENNET_MAX_RING_PAGES (1U<< XENNET_MAX_RING_PAGE_ORDER)
+
+
+#define NET_TX_RING_SIZE(_nr_pages) \
+ __CONST_RING_SIZE(xen_netif_tx, PAGE_SIZE * (_nr_pages))
+#define NET_RX_RING_SIZE(_nr_pages) \
+ __CONST_RING_SIZE(xen_netif_rx, PAGE_SIZE * (_nr_pages))
+
+#define XENNET_MAX_TX_RING_SIZE NET_TX_RING_SIZE(XENNET_MAX_RING_PAGES)
+#define XENNET_MAX_RX_RING_SIZE NET_RX_RING_SIZE(XENNET_MAX_RING_PAGES)
+
+#define TX_MAX_TARGET min_t(int, NET_TX_RING_SIZE(1), 256)
Not using multi-page ring here?
In xennet_create_dev, gnttab_alloc_grant_references allocates
TX_MAX_TARGET number of grant reference for tx. In
xennet_release_tx_bufs, NET_TX_RING_SIZE(np->tx_ring_pages) numbers of
grants are processed. And NET_RX_RING_SIZE(np->tx_ring_pages) is totally
different from TX_MAX_TARGET if np->rx_ring_pages is not 1. Although
skb_entry_is_link helps to not release invalid grants, lots of null loop
seems unnecessary. I think TX_MAX_TARGET should be changed into some
variableconnected with np->tx_ring_pages. Or you intended to use one
page ring here?
struct netfront_stats {
u64 rx_packets;
@@ -80,6 +90,11 @@ struct netfront_stats {
};
struct netfront_info {
+ /* Statistics */
+ struct netfront_stats __percpu *stats;
+
+ unsigned long rx_gso_checksum_fixup;
+
struct list_head list;
struct net_device *netdev;
@@ -90,7 +105,9 @@ struct netfront_info {
spinlock_t tx_lock;
struct xen_netif_tx_front_ring tx;
- int tx_ring_ref;
+ int tx_ring_ref[XENNET_MAX_RING_PAGES];
+ unsigned int tx_ring_page_order;
+ unsigned int tx_ring_pages;
/*
* {tx,rx}_skbs store outstanding skbuffs. Free tx_skb entries
@@ -104,36 +121,33 @@ struct netfront_info {
union skb_entry {
struct sk_buff *skb;
unsigned long link;
- } tx_skbs[NET_TX_RING_SIZE];
+ } tx_skbs[XENNET_MAX_TX_RING_SIZE];
grant_ref_t gref_tx_head;
- grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
+ grant_ref_t grant_tx_ref[XENNET_MAX_TX_RING_SIZE];
unsigned tx_skb_freelist;
spinlock_t rx_lock ____cacheline_aligned_in_smp;
struct xen_netif_rx_front_ring rx;
- int rx_ring_ref;
+ int rx_ring_ref[XENNET_MAX_RING_PAGES];
+ unsigned int rx_ring_page_order;
+ unsigned int rx_ring_pages;
/* Receive-ring batched refills. */
#define RX_MIN_TARGET 8
#define RX_DFL_MIN_TARGET 64
-#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE, 256)
+#define RX_MAX_TARGET min_t(int, NET_RX_RING_SIZE(1), 256)
Not using multi-page ring here?
(See comments of tx side above)
Thanks
Annie
unsigned rx_min_target, rx_max_target, rx_target;
struct sk_buff_head rx_batch;
struct timer_list rx_refill_timer;
- struct sk_buff *rx_skbs[NET_RX_RING_SIZE];
+ struct sk_buff *rx_skbs[XENNET_MAX_RX_RING_SIZE];
grant_ref_t gref_rx_head;
- grant_ref_t grant_rx_ref[NET_RX_RING_SIZE];
-
- unsigned long rx_pfn_array[NET_RX_RING_SIZE];
- struct multicall_entry rx_mcl[NET_RX_RING_SIZE+1];
- struct mmu_update rx_mmu[NET_RX_RING_SIZE];
-
- /* Statistics */
- struct netfront_stats __percpu *stats;
+ grant_ref_t grant_rx_ref[XENNET_MAX_RX_RING_SIZE];
- unsigned long rx_gso_checksum_fixup;
+ unsigned long rx_pfn_array[XENNET_MAX_RX_RING_SIZE];
+ struct multicall_entry rx_mcl[XENNET_MAX_RX_RING_SIZE+1];
+ struct mmu_update rx_mmu[XENNET_MAX_RX_RING_SIZE];
};
struct netfront_rx_info {
@@ -171,15 +185,15 @@ static unsigned short get_id_from_freelist(unsigned *head,
return id;
}
-static int xennet_rxidx(RING_IDX idx)
+static int xennet_rxidx(RING_IDX idx, struct netfront_info *info)
{
- return idx& (NET_RX_RING_SIZE - 1);
+ return idx& (NET_RX_RING_SIZE(info->rx_ring_pages) - 1);
}
static struct sk_buff *xennet_get_rx_skb(struct netfront_info *np,
RING_IDX ri)
{
- int i = xennet_rxidx(ri);
+ int i = xennet_rxidx(ri, np);
struct sk_buff *skb = np->rx_skbs[i];
np->rx_skbs[i] = NULL;
return skb;
@@ -188,7 +202,7 @@ static struct sk_buff *xennet_get_rx_skb(struct
netfront_info *np,
static grant_ref_t xennet_get_rx_ref(struct netfront_info *np,
RING_IDX ri)
{
- int i = xennet_rxidx(ri);
+ int i = xennet_rxidx(ri, np);
grant_ref_t ref = np->grant_rx_ref[i];
np->grant_rx_ref[i] = GRANT_INVALID_REF;
return ref;
@@ -301,7 +315,7 @@ no_skb:
skb->dev = dev;
- id = xennet_rxidx(req_prod + i);
+ id = xennet_rxidx(req_prod + i, np);
BUG_ON(np->rx_skbs[id]);
np->rx_skbs[id] = skb;
@@ -653,7 +667,7 @@ static int xennet_close(struct net_device *dev)
static void xennet_move_rx_slot(struct netfront_info *np, struct sk_buff *skb,
grant_ref_t ref)
{
- int new = xennet_rxidx(np->rx.req_prod_pvt);
+ int new = xennet_rxidx(np->rx.req_prod_pvt, np);
BUG_ON(np->rx_skbs[new]);
np->rx_skbs[new] = skb;
@@ -1109,7 +1123,7 @@ static void xennet_release_tx_bufs(struct netfront_info
*np)
struct sk_buff *skb;
int i;
- for (i = 0; i< NET_TX_RING_SIZE; i++) {
+ for (i = 0; i< NET_TX_RING_SIZE(np->tx_ring_pages); i++) {
/* Skip over entries which are actually freelist references */
if (skb_entry_is_link(&np->tx_skbs[i]))
continue;
@@ -1143,7 +1157,7 @@ static void xennet_release_rx_bufs(struct netfront_info
*np)
spin_lock_bh(&np->rx_lock);
- for (id = 0; id< NET_RX_RING_SIZE; id++) {
+ for (id = 0; id< NET_RX_RING_SIZE(np->rx_ring_pages); id++) {
ref = np->grant_rx_ref[id];
if (ref == GRANT_INVALID_REF) {
unused++;
@@ -1324,13 +1338,13 @@ static struct net_device *xennet_create_dev(struct
xenbus_device *dev)
/* Initialise tx_skbs as a free chain containing every entry. */
np->tx_skb_freelist = 0;
- for (i = 0; i< NET_TX_RING_SIZE; i++) {
+ for (i = 0; i< XENNET_MAX_TX_RING_SIZE; i++) {
skb_entry_set_link(&np->tx_skbs[i], i+1);
np->grant_tx_ref[i] = GRANT_INVALID_REF;
}
/* Clear out rx_skbs */
- for (i = 0; i< NET_RX_RING_SIZE; i++) {
+ for (i = 0; i< XENNET_MAX_RX_RING_SIZE; i++) {
np->rx_skbs[i] = NULL;
np->grant_rx_ref[i] = GRANT_INVALID_REF;
}
@@ -1428,13 +1442,6 @@ static int netfront_probe(struct xenbus_device *dev,
return err;
}
-static void xennet_end_access(int ref, void *page)
-{
- /* This frees the page as a side-effect */
- if (ref != GRANT_INVALID_REF)
- gnttab_end_foreign_access(ref, 0, (unsigned long)page);
-}
-
static void xennet_disconnect_backend(struct netfront_info *info)
{
/* Stop old i/f to prevent errors whilst we rebuild the state. */
@@ -1448,12 +1455,12 @@ static void xennet_disconnect_backend(struct
netfront_info *info)
unbind_from_irqhandler(info->netdev->irq, info->netdev);
info->evtchn = info->netdev->irq = 0;
- /* End access and free the pages */
- xennet_end_access(info->tx_ring_ref, info->tx.sring);
- xennet_end_access(info->rx_ring_ref, info->rx.sring);
+ xenbus_unmap_ring_vfree(info->xbdev, (void *)info->tx.sring);
+ free_pages((unsigned long)info->tx.sring, info->tx_ring_page_order);
+
+ xenbus_unmap_ring_vfree(info->xbdev, (void *)info->rx.sring);
+ free_pages((unsigned long)info->rx.sring, info->rx_ring_page_order);
- info->tx_ring_ref = GRANT_INVALID_REF;
- info->rx_ring_ref = GRANT_INVALID_REF;
info->tx.sring = NULL;
info->rx.sring = NULL;
}
@@ -1501,11 +1508,14 @@ static int setup_netfront(struct xenbus_device *dev,
struct netfront_info *info)
struct xen_netif_tx_sring *txs;
struct xen_netif_rx_sring *rxs;
int err;
- int grefs[1];
struct net_device *netdev = info->netdev;
+ unsigned int max_tx_ring_page_order, max_rx_ring_page_order;
+ int i;
- info->tx_ring_ref = GRANT_INVALID_REF;
- info->rx_ring_ref = GRANT_INVALID_REF;
+ for (i = 0; i< XENNET_MAX_RING_PAGES; i++) {
+ info->tx_ring_ref[i] = GRANT_INVALID_REF;
+ info->rx_ring_ref[i] = GRANT_INVALID_REF;
+ }
info->rx.sring = NULL;
info->tx.sring = NULL;
netdev->irq = 0;
@@ -1516,50 +1526,100 @@ static int setup_netfront(struct xenbus_device *dev,
struct netfront_info *info)
goto fail;
}
- txs = (struct xen_netif_tx_sring *)get_zeroed_page(GFP_NOIO |
__GFP_HIGH);
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "max-tx-ring-page-order", "%u",
+ &max_tx_ring_page_order);
+ if (err< 0) {
+ info->tx_ring_page_order = 0;
+ dev_info(&dev->dev, "single tx ring\n");
+ } else {
+ if (max_tx_ring_page_order> XENNET_MAX_RING_PAGE_ORDER) {
+ dev_info(&dev->dev,
+ "backend ring page order %d too large, clamp to
%d\n",
+ max_tx_ring_page_order,
+ XENNET_MAX_RING_PAGE_ORDER);
+ max_tx_ring_page_order = XENNET_MAX_RING_PAGE_ORDER;
+ }
+ info->tx_ring_page_order = max_tx_ring_page_order;
+ dev_info(&dev->dev, "multi-page tx ring, order = %d\n",
+ info->tx_ring_page_order);
+ }
+ info->tx_ring_pages = (1U<< info->tx_ring_page_order);
+
+ txs = (struct xen_netif_tx_sring *)
+ __get_free_pages(__GFP_ZERO | GFP_NOIO | __GFP_HIGH,
+ info->tx_ring_page_order);
if (!txs) {
err = -ENOMEM;
xenbus_dev_fatal(dev, err, "allocating tx ring page");
goto fail;
}
SHARED_RING_INIT(txs);
- FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE);
+ FRONT_RING_INIT(&info->tx, txs, PAGE_SIZE * info->tx_ring_pages);
+
+ err = xenbus_grant_ring(dev, txs, info->tx_ring_pages,
+ info->tx_ring_ref);
+ if (err< 0)
+ goto grant_tx_ring_fail;
- err = xenbus_grant_ring(dev, txs, 1, grefs);
+ err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+ "max-rx-ring-page-order", "%u",
+ &max_rx_ring_page_order);
if (err< 0) {
- free_page((unsigned long)txs);
- goto fail;
+ info->rx_ring_page_order = 0;
+ dev_info(&dev->dev, "single rx ring\n");
+ } else {
+ if (max_rx_ring_page_order> XENNET_MAX_RING_PAGE_ORDER) {
+ dev_info(&dev->dev,
+ "backend ring page order %d too large, clamp to
%d\n",
+ max_rx_ring_page_order,
+ XENNET_MAX_RING_PAGE_ORDER);
+ max_rx_ring_page_order = XENNET_MAX_RING_PAGE_ORDER;
+ }
+ info->rx_ring_page_order = max_rx_ring_page_order;
+ dev_info(&dev->dev, "multi-page rx ring, order = %d\n",
+ info->rx_ring_page_order);
}
+ info->rx_ring_pages = (1U<< info->rx_ring_page_order);
- info->tx_ring_ref = grefs[0];
- rxs = (struct xen_netif_rx_sring *)get_zeroed_page(GFP_NOIO |
__GFP_HIGH);
+ rxs = (struct xen_netif_rx_sring *)
+ __get_free_pages(__GFP_ZERO | GFP_NOIO | __GFP_HIGH,
+ info->rx_ring_page_order);
if (!rxs) {
err = -ENOMEM;
xenbus_dev_fatal(dev, err, "allocating rx ring page");
- goto fail;
+ goto alloc_rx_ring_fail;
}
SHARED_RING_INIT(rxs);
- FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE);
+ FRONT_RING_INIT(&info->rx, rxs, PAGE_SIZE * info->rx_ring_pages);
- err = xenbus_grant_ring(dev, rxs, 1, grefs);
- if (err< 0) {
- free_page((unsigned long)rxs);
- goto fail;
- }
- info->rx_ring_ref = grefs[0];
+ err = xenbus_grant_ring(dev, rxs, info->rx_ring_pages,
+ info->rx_ring_ref);
+ if (err< 0)
+ goto grant_rx_ring_fail;
err = xenbus_alloc_evtchn(dev,&info->evtchn);
if (err)
- goto fail;
+ goto alloc_evtchn_fail;
err = bind_evtchn_to_irqhandler(info->evtchn, xennet_interrupt,
0, netdev->name, netdev);
if (err< 0)
- goto fail;
+ goto bind_fail;
netdev->irq = err;
return 0;
- fail:
+bind_fail:
+ xenbus_free_evtchn(dev, info->evtchn);
+alloc_evtchn_fail:
+ xenbus_unmap_ring_vfree(info->xbdev, (void *)info->rx.sring);
+grant_rx_ring_fail:
+ free_pages((unsigned long)info->rx.sring, info->rx_ring_page_order);
+alloc_rx_ring_fail:
+ xenbus_unmap_ring_vfree(info->xbdev, (void *)info->tx.sring);
+grant_tx_ring_fail:
+ free_pages((unsigned long)info->tx.sring, info->tx_ring_page_order);
+fail:
return err;
}
@@ -1570,6 +1630,7 @@ static int talk_to_netback(struct xenbus_device *dev,
const char *message;
struct xenbus_transaction xbt;
int err;
+ int i;
/* Create shared ring, alloc event channel. */
err = setup_netfront(dev, info);
@@ -1583,18 +1644,58 @@ again:
goto destroy_ring;
}
- err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u",
- info->tx_ring_ref);
- if (err) {
- message = "writing tx ring-ref";
- goto abort_transaction;
+ if (info->tx_ring_page_order == 0) {
+ err = xenbus_printf(xbt, dev->nodename, "tx-ring-ref", "%u",
+ info->tx_ring_ref[0]);
+ if (err) {
+ message = "writing tx ring-ref";
+ goto abort_transaction;
+ }
+ } else {
+ err = xenbus_printf(xbt, dev->nodename, "tx-ring-order", "%u",
+ info->tx_ring_page_order);
+ if (err) {
+ message = "writing tx-ring-order";
+ goto abort_transaction;
+ }
+ for (i = 0; i< info->tx_ring_pages; i++) {
+ char name[sizeof("tx-ring-ref")+3];
+ snprintf(name, sizeof(name), "tx-ring-ref%u", i);
+ err = xenbus_printf(xbt, dev->nodename, name, "%u",
+ info->tx_ring_ref[i]);
+ if (err) {
+ message = "writing tx ring-ref";
+ goto abort_transaction;
+ }
+ }
}
- err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u",
- info->rx_ring_ref);
- if (err) {
- message = "writing rx ring-ref";
- goto abort_transaction;
+
+ if (info->rx_ring_page_order == 0) {
+ err = xenbus_printf(xbt, dev->nodename, "rx-ring-ref", "%u",
+ info->rx_ring_ref[0]);
+ if (err) {
+ message = "writing rx ring-ref";
+ goto abort_transaction;
+ }
+ } else {
+ err = xenbus_printf(xbt, dev->nodename, "rx-ring-order", "%u",
+ info->rx_ring_page_order);
+ if (err) {
+ message = "writing rx-ring-order";
+ goto abort_transaction;
+ }
+ for (i = 0; i< info->rx_ring_pages; i++) {
+ char name[sizeof("rx-ring-ref")+3];
+ snprintf(name, sizeof(name), "rx-ring-ref%u", i);
+ err = xenbus_printf(xbt, dev->nodename, name, "%u",
+ info->rx_ring_ref[i]);
+ if (err) {
+ message = "writing rx ring-ref";
+ goto abort_transaction;
+ }
+ }
}
+
err = xenbus_printf(xbt, dev->nodename,
"event-channel", "%u", info->evtchn);
if (err) {
@@ -1681,7 +1782,8 @@ static int xennet_connect(struct net_device *dev)
xennet_release_tx_bufs(np);
/* Step 2: Rebuild the RX buffer freelist and the RX ring itself. */
- for (requeue_idx = 0, i = 0; i< NET_RX_RING_SIZE; i++) {
+ for (requeue_idx = 0, i = 0; i< NET_RX_RING_SIZE(np->rx_ring_pages);
+ i++) {
skb_frag_t *frag;
const struct page *page;
if (!np->rx_skbs[i])
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