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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [RFC PATCH V2 4/8] netback: switch to per-cpu scratch space.
In the 1:1 model, given that there are maximum nr_online_cpus netbacks
running, we can use per-cpu scratch space, thus shrinking size of
struct xen_netbk.
Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
drivers/net/xen-netback/common.h | 13 ++++
drivers/net/xen-netback/netback.c | 134 ++++++++++++++++++++++++-------------
2 files changed, 100 insertions(+), 47 deletions(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 31c331c..3b85563 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -45,6 +45,19 @@
#include <xen/grant_table.h>
#include <xen/xenbus.h>
+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 pending_tx_info {
struct xen_netif_tx_request req;
};
diff --git a/drivers/net/xen-netback/netback.c
b/drivers/net/xen-netback/netback.c
index 7378d63..714f508 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1,3 +1,4 @@
+
/*
* Back-end of the driver for virtual network devices. This portion of the
* driver exports a 'unified' network-device interface that can be accessed
@@ -47,18 +48,17 @@
#include <asm/xen/hypercall.h>
#include <asm/xen/page.h>
-struct netbk_rx_meta {
- int id;
- int size;
- int gso_size;
-};
-#define MAX_PENDING_REQS 256
+struct gnttab_copy *tx_copy_ops;
-/* Discriminate from any valid pending_idx value. */
-#define INVALID_PENDING_IDX 0xFFFF
+/*
+ * 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;
+struct netbk_rx_meta *meta;
-#define MAX_BUFFER_OFFSET PAGE_SIZE
struct xen_netbk {
struct sk_buff_head rx_queue;
@@ -71,17 +71,7 @@ struct xen_netbk {
struct xenvif *vif;
- struct gnttab_copy tx_copy_ops[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 void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx);
@@ -508,9 +498,12 @@ void xen_netbk_rx_action(struct xen_netbk *netbk)
struct skb_cb_overlay *sco;
int need_to_notify = 0;
+ struct gnttab_copy *gco = get_cpu_ptr(grant_copy_op);
+ struct netbk_rx_meta *m = get_cpu_ptr(meta);
+
struct netrx_pending_operations npo = {
- .copy = netbk->grant_copy_op,
- .meta = netbk->meta,
+ .copy = gco,
+ .meta = m,
};
skb_queue_head_init(&rxq);
@@ -533,13 +526,16 @@ void xen_netbk_rx_action(struct xen_netbk *netbk)
break;
}
- BUG_ON(npo.meta_prod > ARRAY_SIZE(netbk->meta));
+ BUG_ON(npo.meta_prod > MAX_PENDING_REQS);
- if (!npo.copy_prod)
+ if (!npo.copy_prod) {
+ put_cpu_ptr(gco);
+ put_cpu_ptr(m);
return;
+ }
- BUG_ON(npo.copy_prod > ARRAY_SIZE(netbk->grant_copy_op));
- ret = HYPERVISOR_grant_table_op(GNTTABOP_copy, &netbk->grant_copy_op,
+ BUG_ON(npo.copy_prod > (2 * XEN_NETIF_RX_RING_SIZE));
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_copy, gco,
npo.copy_prod);
BUG_ON(ret != 0);
@@ -548,14 +544,14 @@ void xen_netbk_rx_action(struct xen_netbk *netbk)
vif = netdev_priv(skb->dev);
- if (netbk->meta[npo.meta_cons].gso_size && vif->gso_prefix) {
+ if (m[npo.meta_cons].gso_size && vif->gso_prefix) {
resp = RING_GET_RESPONSE(&vif->rx,
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 = m[npo.meta_cons].gso_size;
+ resp->id = m[npo.meta_cons].id;
resp->status = sco->meta_slots_used;
npo.meta_cons++;
@@ -580,12 +576,12 @@ void xen_netbk_rx_action(struct xen_netbk *netbk)
flags |= XEN_NETRXF_data_validated;
offset = 0;
- resp = make_rx_response(vif, netbk->meta[npo.meta_cons].id,
+ resp = make_rx_response(vif, m[npo.meta_cons].id,
status, offset,
- netbk->meta[npo.meta_cons].size,
+ m[npo.meta_cons].size,
flags);
- if (netbk->meta[npo.meta_cons].gso_size && !vif->gso_prefix) {
+ if (m[npo.meta_cons].gso_size && !vif->gso_prefix) {
struct xen_netif_extra_info *gso =
(struct xen_netif_extra_info *)
RING_GET_RESPONSE(&vif->rx,
@@ -593,7 +589,7 @@ void xen_netbk_rx_action(struct xen_netbk *netbk)
resp->flags |= XEN_NETRXF_extra_info;
- gso->u.gso.size = netbk->meta[npo.meta_cons].gso_size;
+ gso->u.gso.size = m[npo.meta_cons].gso_size;
gso->u.gso.type = XEN_NETIF_GSO_TYPE_TCPV4;
gso->u.gso.pad = 0;
gso->u.gso.features = 0;
@@ -603,7 +599,7 @@ void xen_netbk_rx_action(struct xen_netbk *netbk)
}
netbk_add_frag_responses(vif, status,
- netbk->meta + npo.meta_cons + 1,
+ m + npo.meta_cons + 1,
sco->meta_slots_used);
RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret);
@@ -621,6 +617,9 @@ void xen_netbk_rx_action(struct xen_netbk *netbk)
if (!skb_queue_empty(&netbk->rx_queue))
xen_netbk_kick_thread(netbk);
+
+ put_cpu_ptr(gco);
+ put_cpu_ptr(m);
}
void xen_netbk_queue_tx_skb(struct xenvif *vif, struct sk_buff *skb)
@@ -1052,9 +1051,10 @@ static bool tx_credit_exceeded(struct xenvif *vif,
unsigned size)
return false;
}
-static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk)
+static unsigned xen_netbk_tx_build_gops(struct xen_netbk *netbk,
+ struct gnttab_copy *tco)
{
- struct gnttab_copy *gop = netbk->tx_copy_ops, *request_gop;
+ struct gnttab_copy *gop = tco, *request_gop;
struct sk_buff *skb;
int ret;
struct xenvif *vif = netbk->vif;
@@ -1214,17 +1214,18 @@ static unsigned xen_netbk_tx_build_gops(struct
xen_netbk *netbk)
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 - tco) >= MAX_PENDING_REQS)
break;
}
- return gop - netbk->tx_copy_ops;
+ return gop - tco;
}
static void xen_netbk_tx_submit(struct xen_netbk *netbk,
+ struct gnttab_copy *tco,
int *work_done, int budget)
{
- struct gnttab_copy *gop = netbk->tx_copy_ops;
+ struct gnttab_copy *gop = tco;
struct sk_buff *skb;
struct xenvif *vif = netbk->vif;
@@ -1305,19 +1306,25 @@ void xen_netbk_tx_action(struct xen_netbk *netbk, int
*work_done, int budget)
{
unsigned nr_gops;
int ret;
+ struct gnttab_copy *tco;
if (unlikely(!tx_work_todo(netbk)))
return;
- nr_gops = xen_netbk_tx_build_gops(netbk);
+ tco = get_cpu_ptr(tx_copy_ops);
- if (nr_gops == 0)
- return;
- ret = HYPERVISOR_grant_table_op(GNTTABOP_copy,
- netbk->tx_copy_ops, nr_gops);
+ nr_gops = xen_netbk_tx_build_gops(netbk, tco);
+
+ if (nr_gops == 0) {
+ put_cpu_ptr(tco);
+ return 0;
+ }
+
+ ret = HYPERVISOR_grant_table_op(GNTTABOP_copy, tco, nr_gops);
BUG_ON(ret);
- xen_netbk_tx_submit(netbk, work_done, budget);
+ xen_netbk_tx_submit(netbk, tco, work_done, budget);
+ put_cpu_ptr(tco);
}
static void xen_netbk_idx_release(struct xen_netbk *netbk, u16 pending_idx)
@@ -1503,17 +1510,47 @@ int xen_netbk_kthread(void *data)
static int __init netback_init(void)
{
- int rc = 0;
+ int rc = -ENOMEM;
if (!xen_domain())
return -ENODEV;
+ tx_copy_ops = __alloc_percpu(sizeof(struct gnttab_copy)
+ * MAX_PENDING_REQS,
+ __alignof__(struct gnttab_copy));
+ if (!tx_copy_ops)
+ goto failed_init;
+
+ grant_copy_op = __alloc_percpu(sizeof(struct gnttab_copy)
+ * 2 * XEN_NETIF_RX_RING_SIZE,
+ __alignof__(struct gnttab_copy));
+ if (!grant_copy_op)
+ goto failed_init_gco;
+
+ meta = __alloc_percpu(sizeof(struct netbk_rx_meta)
+ * 2 * XEN_NETIF_RX_RING_SIZE,
+ __alignof__(struct netbk_rx_meta));
+ if (!meta)
+ goto failed_init_meta;
+
rc = page_pool_init();
if (rc)
- goto failed_init;
+ goto failed_init_pool;
+
+ rc = xenvif_xenbus_init();
+ if (rc)
+ goto failed_init_xenbus;
- return xenvif_xenbus_init();
+ return rc;
+failed_init_xenbus:
+ page_pool_destroy();
+failed_init_pool:
+ free_percpu(meta);
+failed_init_meta:
+ free_percpu(grant_copy_op);
+failed_init_gco:
+ free_percpu(tx_copy_ops);
failed_init:
return rc;
@@ -1525,6 +1562,9 @@ static void __exit netback_exit(void)
{
xenvif_xenbus_exit();
page_pool_destroy();
+ free_percpu(meta);
+ free_percpu(grant_copy_op);
+ free_percpu(tx_copy_ops);
}
module_exit(netback_exit);
--
1.7.2.5
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