2010-07-07 11:12:45 +00:00
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From: jbeulich@novell.com
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Subject: netback: reduce overhead of IRQ recording
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Patch-mainline: obsolete
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Since both NR_PIRQS and NR_DYNIRQS are no longer hardcoded, the
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(memory) overhead of tracking which ones to send notifications to can
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be pretty unbounded. Also, store the dynirq rather than the raw irq
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to push up the limit where the type of notify_list needs to become
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'int' rather than 'u16'.
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2011-04-19 20:09:59 +00:00
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--- head-2011-02-17.orig/drivers/xen/netback/interface.c 2011-02-17 10:18:52.000000000 +0100
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+++ head-2011-02-17/drivers/xen/netback/interface.c 2011-02-17 10:33:17.000000000 +0100
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@@ -381,6 +381,7 @@ int netif_map(netif_t *netif, unsigned l
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2010-07-07 11:12:45 +00:00
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netif->dev->name, netif);
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if (err < 0)
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goto err_hypervisor;
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+ BUG_ON(err < DYNIRQ_BASE || err >= DYNIRQ_BASE + NR_DYNIRQS);
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netif->irq = err;
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disable_irq(netif->irq);
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2011-04-19 20:09:59 +00:00
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--- head-2011-02-17.orig/drivers/xen/netback/netback.c 2011-01-03 13:29:58.000000000 +0100
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+++ head-2011-02-17/drivers/xen/netback/netback.c 2011-01-03 13:30:08.000000000 +0100
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@@ -593,8 +593,12 @@ static void net_rx_action(unsigned long
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2010-07-07 11:12:45 +00:00
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static mmu_update_t rx_mmu[NET_RX_RING_SIZE];
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static gnttab_transfer_t grant_trans_op[NET_RX_RING_SIZE];
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static gnttab_copy_t grant_copy_op[NET_RX_RING_SIZE];
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- static unsigned char rx_notify[NR_IRQS];
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+ static DECLARE_BITMAP(rx_notify, NR_DYNIRQS);
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+#if NR_DYNIRQS <= 0x10000
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static u16 notify_list[NET_RX_RING_SIZE];
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+#else
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+ static int notify_list[NET_RX_RING_SIZE];
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+#endif
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static struct netbk_rx_meta meta[NET_RX_RING_SIZE];
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struct netrx_pending_operations npo = {
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2011-04-19 20:09:59 +00:00
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@@ -748,11 +752,9 @@ static void net_rx_action(unsigned long
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2010-07-07 11:12:45 +00:00
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nr_frags);
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RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&netif->rx, ret);
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- irq = netif->irq;
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- if (ret && !rx_notify[irq]) {
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- rx_notify[irq] = 1;
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+ irq = netif->irq - DYNIRQ_BASE;
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+ if (ret && !__test_and_set_bit(irq, rx_notify))
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notify_list[notify_nr++] = irq;
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- }
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if (netif_queue_stopped(netif->dev) &&
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netif_schedulable(netif) &&
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2011-04-19 20:09:59 +00:00
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@@ -767,8 +769,8 @@ static void net_rx_action(unsigned long
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2010-07-07 11:12:45 +00:00
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while (notify_nr != 0) {
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irq = notify_list[--notify_nr];
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- rx_notify[irq] = 0;
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- notify_remote_via_irq(irq);
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+ __clear_bit(irq, rx_notify);
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+ notify_remote_via_irq(irq + DYNIRQ_BASE);
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}
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/* More work to do? */
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