megaraid: Add support for change_queue_depth

PATCH [email protected] 1 participant 1 message Jul 7, 2006 SCSI

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2006-07-07 03:22 UTC #0 lore raw

Quoted 6 lines · ---- "Ju

Hi,
Quoted 2 lines · brking
Adds support for change_queue_depth so that device queue depth can be changed at runtime through sysfs.
Can you share any reason to have queue depth chanaged at runtime? It is set with MBOX_MAX_SCSI_CMDS at driver attach.

For my own purposes, I've been wanting to try different max queue depths to see how it affects my overall performance when memory is fragmented after the system has been up for a while, so rebooting to try a different queue depth doesn't help me much.

Brian

Quoted 61 lines

Thank you,
Seokmann
Quoted 56 lines
-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Wednesday, July 05, 2006 6:00 PM
To: Kolli, Neela
Cc: Ju, Seokmann; [email protected]; [email protected]
Subject: [patch 1/1] megaraid: Add support for change_queue_depth
Adds support for change_queue_depth so that device queue depth can be changed at runtime through sysfs.
Signed-off-by <[email protected]>
---
diff -puN drivers/scsi/megaraid/megaraid_mbox.c~megaraid_change_queue_de pth drivers/scsi/megaraid/megaraid_mbox.c
---
linux-2.6/drivers/scsi/megaraid/megaraid_mbox.c~megaraid_chang
e_queue_depth 2006-07-05 14:00:04.000000000 -0500
+++ linux-2.6-brking/drivers/scsi/megaraid/megaraid_mbox.c
2006-07-05 16:53:36.000000000 -0500
(quoted diff) +15 -0
@@ -330,6 +330,21 @@ static struct device_attribute *megaraid
 	NULL,
 };
 
+/**
+ * megaraid_change_queue_depth - Change the device's queue depth
+ * @sdev:	scsi device struct
+ * @qdepth:	depth to set
+ *
+ * Return value:
+ * 	actual depth set
+ **/
+static int megaraid_change_queue_depth(struct scsi_device 
 *sdev, int qdepth)
+{
+	if (qdepth > MBOX_MAX_SCSI_CMDS)
+		qdepth = MBOX_MAX_SCSI_CMDS;
+	scsi_adjust_queue_depth(sdev, 0, qdepth);
+	return sdev->queue_depth;
+}
 
 /*
* Scsi host template for megaraid unified driver
(quoted diff) +1 -0
@@ -343,6 +358,7 @@ static struct scsi_host_template megarai
 	.eh_device_reset_handler	= megaraid_reset_handler,
 	.eh_bus_reset_handler		= megaraid_reset_handler,
 	.eh_host_reset_handler		= megaraid_reset_handler,
+	.change_queue_depth		= megaraid_change_queue_depth,
 	.use_clustering			= ENABLE_CLUSTERING,
 	.sdev_attrs			= megaraid_sdev_attrs,
 	.shost_attrs			= megaraid_shost_attrs,
_