From: Arthur Kepner <akepner@sgi•com>
To: netdev@vger•kernel.org
Subject: [PATCH] mlx4_core: module param to limit msix vec allocation
Date: Thu, 26 Aug 2010 10:06:46 -0700 [thread overview]
Message-ID: <20100826170646.GB27157@sgi.com> (raw)
(Resending to netdev. Previously sent to linux-rdma)
The mlx4_core driver allocates 'nreq' msix vectors (and irqs),
where:
nreq = min_t(int, dev->caps.num_eqs - dev->caps.reserved_eqs,
num_possible_cpus() + 1);
ConnectX HCAs support 512 event queues (4 reserved). On a system
with enough processors, we get:
mlx4_core 0006:01:00.0: Requested 508 vectors, but only 256 MSI-X vectors available, trying again
Further attempts (by other drivers) to allocate interrupts fail,
because mlx4_core got 'em all.
Use a module parameter to limit the number of MSI-X vectors that
the mlx4_core driver will attempt to allocate.
Signed-off-by: Arthur Kepner <akepner@sgi•com>
---
diff --git a/drivers/net/mlx4/main.c b/drivers/net/mlx4/main.c
index 5102ab1..3eba2f3 100644
--- a/drivers/net/mlx4/main.c
+++ b/drivers/net/mlx4/main.c
@@ -68,6 +68,10 @@ static int msi_x = 1;
module_param(msi_x, int, 0444);
MODULE_PARM_DESC(msi_x, "attempt to use MSI-X if nonzero");
+static int max_msi_x_vec = 64;
+module_param(max_msi_x_vec, int, 0444);
+MODULE_PARM_DESC(max_msi_x_vec, "max MSI-X vectors we'll attempt to allocate");
+
#else /* CONFIG_PCI_MSI */
#define msi_x (0)
@@ -968,8 +972,10 @@ static void mlx4_enable_msi_x(struct mlx4_dev *dev)
int i;
if (msi_x) {
+ nreq = min_t(int, num_possible_cpus() + 1, max_msi_x_vec);
nreq = min_t(int, dev->caps.num_eqs - dev->caps.reserved_eqs,
- num_possible_cpus() + 1);
+ nreq);
+
entries = kcalloc(nreq, sizeof *entries, GFP_KERNEL);
if (!entries)
goto no_msi;
next reply other threads:[~2010-08-26 17:06 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-26 17:06 Arthur Kepner [this message]
2010-08-26 19:24 ` [PATCH] mlx4_core: module param to limit msix vec allocation David Miller
2010-09-03 20:30 ` Arthur Kepner
2010-09-03 21:46 ` David Miller
2010-09-03 22:13 ` Arthur Kepner
2010-09-04 2:30 ` David Miller
2010-09-06 17:42 ` Arthur Kepner
2010-09-06 19:51 ` David Miller
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