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Date: Thu, 27 Aug 2009 14:02:10 -0700
From: Ron Mercer <ron.mercer@...gic.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, ron.mercer@...gic.com
Subject: [net-next PATCH 2/3] qlge: Allow running MSIx with fewer vectors.
Currently we downshift to MSI/Legacy if we don't get enough vectors for
cpu_count RSS rings plus cpu_count TX completion rings. This patch
allows running MSIX with the vector count that the platform provides.
Signed-off-by: Ron Mercer <ron.mercer@...gic.com>
---
drivers/net/qlge/qlge_main.c | 85 +++++++++++++++++++-----------------------
1 files changed, 38 insertions(+), 47 deletions(-)
diff --git a/drivers/net/qlge/qlge_main.c b/drivers/net/qlge/qlge_main.c
index 89ea9c7..0cbda4d 100644
--- a/drivers/net/qlge/qlge_main.c
+++ b/drivers/net/qlge/qlge_main.c
@@ -2815,17 +2815,20 @@ static void ql_disable_msix(struct ql_adapter *qdev)
}
}
+/* We start by trying to get the number of vectors
+ * stored in qdev->intr_count. If we don't get that
+ * many then we reduce the count and try again.
+ */
static void ql_enable_msix(struct ql_adapter *qdev)
{
- int i;
+ int i, err;
- qdev->intr_count = 1;
/* Get the MSIX vectors. */
if (irq_type == MSIX_IRQ) {
/* Try to alloc space for the msix struct,
* if it fails then go to MSI/legacy.
*/
- qdev->msi_x_entry = kcalloc(qdev->rx_ring_count,
+ qdev->msi_x_entry = kcalloc(qdev->intr_count,
sizeof(struct msix_entry),
GFP_KERNEL);
if (!qdev->msi_x_entry) {
@@ -2833,26 +2836,36 @@ static void ql_enable_msix(struct ql_adapter *qdev)
goto msi;
}
- for (i = 0; i < qdev->rx_ring_count; i++)
+ for (i = 0; i < qdev->intr_count; i++)
qdev->msi_x_entry[i].entry = i;
- if (!pci_enable_msix
- (qdev->pdev, qdev->msi_x_entry, qdev->rx_ring_count)) {
- set_bit(QL_MSIX_ENABLED, &qdev->flags);
- qdev->intr_count = qdev->rx_ring_count;
- QPRINTK(qdev, IFUP, DEBUG,
- "MSI-X Enabled, got %d vectors.\n",
- qdev->intr_count);
- return;
- } else {
+ /* Loop to get our vectors. We start with
+ * what we want and settle for what we get.
+ */
+ do {
+ err = pci_enable_msix(qdev->pdev,
+ qdev->msi_x_entry, qdev->intr_count);
+ if (err > 0)
+ qdev->intr_count = err;
+ } while (err > 0);
+
+ if (err < 0) {
kfree(qdev->msi_x_entry);
qdev->msi_x_entry = NULL;
QPRINTK(qdev, IFUP, WARNING,
"MSI-X Enable failed, trying MSI.\n");
+ qdev->intr_count = 1;
irq_type = MSI_IRQ;
+ } else if (err == 0) {
+ set_bit(QL_MSIX_ENABLED, &qdev->flags);
+ QPRINTK(qdev, IFUP, INFO,
+ "MSI-X Enabled, got %d vectors.\n",
+ qdev->intr_count);
+ return;
}
}
msi:
+ qdev->intr_count = 1;
if (irq_type == MSI_IRQ) {
if (!pci_enable_msi(qdev->pdev)) {
set_bit(QL_MSI_ENABLED, &qdev->flags);
@@ -2876,8 +2889,6 @@ static void ql_resolve_queues_to_irqs(struct ql_adapter *qdev)
int i = 0;
struct intr_context *intr_context = &qdev->intr_context[0];
- ql_enable_msix(qdev);
-
if (likely(test_bit(QL_MSIX_ENABLED, &qdev->flags))) {
/* Each rx_ring has it's
* own intr_context since we have separate
@@ -3438,40 +3449,20 @@ static int ql_configure_rings(struct ql_adapter *qdev)
int i;
struct rx_ring *rx_ring;
struct tx_ring *tx_ring;
- int cpu_cnt = num_online_cpus();
-
- /*
- * For each processor present we allocate one
- * rx_ring for outbound completions, and one
- * rx_ring for inbound completions. Plus there is
- * always the one default queue. For the CPU
- * counts we end up with the following rx_rings:
- * rx_ring count =
- * one default queue +
- * (CPU count * outbound completion rx_ring) +
- * (CPU count * inbound (RSS) completion rx_ring)
- * To keep it simple we limit the total number of
- * queues to < 32, so we truncate CPU to 8.
- * This limitation can be removed when requested.
+ int cpu_cnt = min(MAX_CPUS, (int)num_online_cpus());
+
+ /* In a perfect world we have one RSS ring for each CPU
+ * and each has it's own vector. To do that we ask for
+ * cpu_cnt vectors. ql_enable_msix() will adjust the
+ * vector count to what we actually get. We then
+ * allocate an RSS ring for each.
+ * Essentially, we are doing min(cpu_count, msix_vector_count).
*/
-
- if (cpu_cnt > MAX_CPUS)
- cpu_cnt = MAX_CPUS;
-
- /*
- * rx_ring[0] is always the default queue.
- */
- /* Allocate outbound completion ring for each CPU. */
+ qdev->intr_count = cpu_cnt;
+ ql_enable_msix(qdev);
+ /* Adjust the RSS ring count to the actual vector count. */
+ qdev->rss_ring_count = qdev->intr_count;
qdev->tx_ring_count = cpu_cnt;
- /* Allocate inbound completion (RSS) ring for each CPU. */
- qdev->rss_ring_count = cpu_cnt;
- /*
- * qdev->rx_ring_count:
- * Total number of rx_rings. This includes the one
- * default queue, a number of outbound completion
- * handler rx_rings, and the number of inbound
- * completion handler rx_rings.
- */
qdev->rx_ring_count = qdev->tx_ring_count + qdev->rss_ring_count;
for (i = 0; i < qdev->tx_ring_count; i++) {
--
1.6.0.2
--
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