[people/teissler/ipfire-2.x.git] / src / patches / suse-2.6.27.25 / patches.xen / xen-netback-nr-irqs

From: jbeulich@novell.com
Subject: netback: reduce overhead of IRQ recording
Patch-mainline: obsolete

Since both NR_PIRQS and NR_DYNIRQS are no longer hardcoded, the
(memory) overhead of tracking which ones to send notifications to can
be pretty unbounded. Also, store the dynirq rather than the raw irq
to push up the limit where the type of notify_list needs to become
'int' rather than 'u16'.

--- head-2009-02-02.orig/drivers/xen/netback/interface.c	2009-02-02 09:40:43.000000000 +0100
+++ head-2009-02-02/drivers/xen/netback/interface.c	2009-02-02 10:20:51.000000000 +0100
@@ -280,6 +280,7 @@ int netif_map(netif_t *netif, unsigned l
 		netif->dev->name, netif);
 	if (err < 0)
 		goto err_hypervisor;
+	BUG_ON(err < DYNIRQ_BASE || err >= DYNIRQ_BASE + NR_DYNIRQS);
 	netif->irq = err;
 	disable_irq(netif->irq);
 
--- head-2009-02-02.orig/drivers/xen/netback/netback.c	2008-12-23 09:35:35.000000000 +0100
+++ head-2009-02-02/drivers/xen/netback/netback.c	2008-12-23 09:35:42.000000000 +0100
@@ -580,8 +580,12 @@ static void net_rx_action(unsigned long 
 	static mmu_update_t rx_mmu[NET_RX_RING_SIZE];
 	static gnttab_transfer_t grant_trans_op[NET_RX_RING_SIZE];
 	static gnttab_copy_t grant_copy_op[NET_RX_RING_SIZE];
-	static unsigned char rx_notify[NR_IRQS];
+	static DECLARE_BITMAP(rx_notify, NR_DYNIRQS);
+#if NR_DYNIRQS <= 0x10000
 	static u16 notify_list[NET_RX_RING_SIZE];
+#else
+	static int notify_list[NET_RX_RING_SIZE];
+#endif
 	static struct netbk_rx_meta meta[NET_RX_RING_SIZE];
 
 	struct netrx_pending_operations npo = {
@@ -730,11 +734,9 @@ static void net_rx_action(unsigned long 
 					 nr_frags);
 
 		RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&netif->rx, ret);
-		irq = netif->irq;
-		if (ret && !rx_notify[irq]) {
-			rx_notify[irq] = 1;
+		irq = netif->irq - DYNIRQ_BASE;
+		if (ret && !__test_and_set_bit(irq, rx_notify))
 			notify_list[notify_nr++] = irq;
-		}
 
 		if (netif_queue_stopped(netif->dev) &&
 		    netif_schedulable(netif) &&
@@ -748,8 +750,8 @@ static void net_rx_action(unsigned long 
 
 	while (notify_nr != 0) {
 		irq = notify_list[--notify_nr];
-		rx_notify[irq] = 0;
-		notify_remote_via_irq(irq);
+		__clear_bit(irq, rx_notify);
+		notify_remote_via_irq(irq + DYNIRQ_BASE);
 	}
 
 	/* More work to do? */
Commit	Line	Data
cc90b958 BS	1	From: jbeulich@novell.com
	2	Subject: netback: reduce overhead of IRQ recording
	3	Patch-mainline: obsolete
	4
	5	Since both NR_PIRQS and NR_DYNIRQS are no longer hardcoded, the
	6	(memory) overhead of tracking which ones to send notifications to can
	7	be pretty unbounded. Also, store the dynirq rather than the raw irq
	8	to push up the limit where the type of notify_list needs to become
	9	'int' rather than 'u16'.
	10
00e5a55c BS	11	--- head-2009-02-02.orig/drivers/xen/netback/interface.c 2009-02-02 09:40:43.000000000 +0100
	12	+++ head-2009-02-02/drivers/xen/netback/interface.c 2009-02-02 10:20:51.000000000 +0100
	13	@@ -280,6 +280,7 @@ int netif_map(netif_t *netif, unsigned l
cc90b958 BS	14	netif->dev->name, netif);
	15	if (err < 0)
	16	goto err_hypervisor;
	17	+ BUG_ON(err < DYNIRQ_BASE \|\| err >= DYNIRQ_BASE + NR_DYNIRQS);
	18	netif->irq = err;
	19	disable_irq(netif->irq);
	20
00e5a55c BS	21	--- head-2009-02-02.orig/drivers/xen/netback/netback.c 2008-12-23 09:35:35.000000000 +0100
	22	+++ head-2009-02-02/drivers/xen/netback/netback.c 2008-12-23 09:35:42.000000000 +0100
	23	@@ -580,8 +580,12 @@ static void net_rx_action(unsigned long
cc90b958 BS	24	static mmu_update_t rx_mmu[NET_RX_RING_SIZE];
	25	static gnttab_transfer_t grant_trans_op[NET_RX_RING_SIZE];
	26	static gnttab_copy_t grant_copy_op[NET_RX_RING_SIZE];
	27	- static unsigned char rx_notify[NR_IRQS];
	28	+ static DECLARE_BITMAP(rx_notify, NR_DYNIRQS);
	29	+#if NR_DYNIRQS <= 0x10000
	30	static u16 notify_list[NET_RX_RING_SIZE];
	31	+#else
	32	+ static int notify_list[NET_RX_RING_SIZE];
	33	+#endif
	34	static struct netbk_rx_meta meta[NET_RX_RING_SIZE];
	35
	36	struct netrx_pending_operations npo = {
00e5a55c	37	@@ -730,11 +734,9 @@ static void net_rx_action(unsigned long
cc90b958 BS	38	nr_frags);
	39
	40	RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&netif->rx, ret);
	41	- irq = netif->irq;
	42	- if (ret && !rx_notify[irq]) {
	43	- rx_notify[irq] = 1;
	44	+ irq = netif->irq - DYNIRQ_BASE;
	45	+ if (ret && !__test_and_set_bit(irq, rx_notify))
	46	notify_list[notify_nr++] = irq;
	47	- }
	48
	49	if (netif_queue_stopped(netif->dev) &&
	50	netif_schedulable(netif) &&
00e5a55c	51	@@ -748,8 +750,8 @@ static void net_rx_action(unsigned long
cc90b958 BS	52
	53	while (notify_nr != 0) {
	54	irq = notify_list[--notify_nr];
	55	- rx_notify[irq] = 0;
	56	- notify_remote_via_irq(irq);
	57	+ __clear_bit(irq, rx_notify);
	58	+ notify_remote_via_irq(irq + DYNIRQ_BASE);
	59	}
	60
	61	/* More work to do? */