netdev - [PATCH net-next 2/3] bnx2x: save RAM in kdump kernel by using a single queue

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Date:	Tue, 25 Feb 2014 16:04:25 +0100
From:	Michal Schmidt <mschmidt@...hat.com>
To:	davem@...emloft.net
Cc:	netdev@...r.kernel.org, ariele@...adcom.com, dmitry@...adcom.com,
	yuvalmin@...adcom.com
Subject: [PATCH net-next 2/3] bnx2x: save RAM in kdump kernel by using a single queue

When running in a kdump kernel, make sure to use only a single ethernet
queue even if a num_queues option in /etc/modprobe.d/*.conf would specify
otherwise. This saves memory, which tends to be scarce in kdump.

This saves about 40 MB in the kdump environment on a setup with
num_queues=8 in the config file.

Signed-off-by: Michal Schmidt <mschmidt@...hat.com>
---
 drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
index 64c17b6..500d38a 100644
--- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
+++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
@@ -62,6 +62,11 @@ static void bnx2x_add_all_napi(struct bnx2x *bp)
 static int bnx2x_calc_num_queues(struct bnx2x *bp)
 {
 	int nq = bnx2x_num_queues ? : netif_get_num_default_rss_queues();
+
+	/* Reduce memory usage in kdump environment by using only one queue */
+	if (reset_devices)
+		nq = 1;
+
 	nq = clamp(nq, 1, BNX2X_MAX_QUEUES(bp));
 	return nq;
 }
-- 
1.8.5.3

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