Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750996AbaLPKMX (ORCPT ); Tue, 16 Dec 2014 05:12:23 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:38573 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750812AbaLPKMV (ORCPT ); Tue, 16 Dec 2014 05:12:21 -0500 From: Bob Liu To: xen-devel@lists.xen.org Cc: konrad.wilk@oracle.com, linux-kernel@vger.kernel.org, david.vrabel@citrix.com, Bob Liu Subject: [PATCH] xen/blkfront: increase the default value of xen_blkif_max_segments Date: Tue, 16 Dec 2014 18:11:36 +0800 Message-Id: <1418724696-23922-1-git-send-email-bob.liu@oracle.com> X-Mailer: git-send-email 1.7.10.4 X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The default maximum value of segments in indirect requests was 32, IO operations with bigger block size(>32*4k) would be split and performance start to drop. Nowadays backend device usually support 512k max_sectors_kb on desktop, and may larger on server machines with high-end storage system. The default size 128k was not very appropriate, this patch increases the default maximum value to 128(128*4k=512k). Signed-off-by: Bob Liu --- drivers/block/xen-blkfront.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 2236c6f..1bf2429 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -94,9 +94,9 @@ static const struct block_device_operations xlvbd_block_fops; * by the backend driver. */ -static unsigned int xen_blkif_max_segments = 32; +static unsigned int xen_blkif_max_segments = 128; module_param_named(max, xen_blkif_max_segments, int, S_IRUGO); -MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests (default is 32)"); +MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests (default is 128)"); #define BLK_RING_SIZE __CONST_RING_SIZE(blkif, PAGE_SIZE) -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/