From: Nicholas Bellinger <nab@linux-iscsi.org>
Date: Tue, 5 Nov 2013 21:16:12 +0000 (-0800)
Subject: ib_isert: Add support for completion interrupt coalescing
X-Git-Tag: v3.13-rc1~5^2~25
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=95b60f078899a9680688bab909d02169e1fd632e;p=pandora-kernel.git

ib_isert: Add support for completion interrupt coalescing

This patch adds support for completion interrupt coalescing that
allows only every ISERT_COMP_BATCH_COUNT (8) to set IB_SEND_SIGNALED,
thus avoiding completion interrupts for every posted iser_tx_desc.

The batch processing is done using a per isert_conn llist that once
IB_SEND_SIGNALED has been set is saved to tx_desc->comp_llnode_batch,
and completion processing of previously posted iser_tx_descs is done
in a single shot from within isert_send_completion() code.

Note this is only done for response PDUs from ISCSI_OP_SCSI_CMD, and
all other control type of PDU responses will force an implicit batch
drain to occur.

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---

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