From patchwork Tue Mar 25 06:58:44 2014

From patchwork Tue Mar 25 06:58:44 2014
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Subject: librdmacm: lazy initialization for ib devices
From: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>
X-Patchwork-Id: 3885371
Message-Id: <20140325065839.GA3794@shamir-pc>
To: linux-rdma@vger.kernel.org
Date: Tue, 25 Mar 2014 08:58:44 +0200

Hi Sean,

Resending the patch with proper mail client.

There was a request by teams in Oracle to decouple the HCA limited
ability to open device context and the rising amount of processes that
run on the servers.
It appear that the lowest capable HCA become the limit to all the
processes that attempt to use the library.
This patch try to decouple this by allowing the process to use the
library w/o implicitly opening the device.
Device will be opened only when needed.

BR, Shamir

LIBRDMACM currently opens a device context per configured HCA. This is
usually done in rdma_create_event_channel() or first time whenever
ucma_init() is called. If a process is only going to use one of the
configured HCAs/RDMA IPs then the remaining device contexts are not
used/required. Opening a device context on each device apriori limits the
maximum number of processes that can be supported on a node to the maximum
number of open context supported per HCA regardless of number of HCAs present
in the system.

Signed-off-by: Shamir Rabinovitch <shamir.rabinovitch@oracle.com>