From 68d95b585f1b67b3c89ce0eb934e221ebeeb5c61 Mon Sep 17 00:00:00 2001 From: Mike Miller Date: Tue, 4 Mar 2008 11:25:15 +0100 Subject: [PATCH] cciss: remove READ_AHEAD define and use block layer defaults This patch removes the #define READ_AHEAD 1024 from the driver and uses the block layer defaults, instead. We have found that under certain workloads the setting can cause a disk connected to the e200 controller to go offline. If the disk hiccups the link may try to downshift but the controller is never notified that the link successfully completed the renegotiation. We've also found that performance using the block layer default of 32 pages was on par with the 1024 setting. We tried setting it to zero at one time based on info from our firmware guys but that killed performance. Turns out we were talking about 2 different read ahead settings. Please consider this for inclusion. Signed-off-by: Mike Miller Signed-off-by: Jens Axboe --- drivers/block/cciss.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/block/cciss.c b/drivers/block/cciss.c index f1e7390683f..55bd35c0f08 100644 --- a/drivers/block/cciss.c +++ b/drivers/block/cciss.c @@ -132,7 +132,6 @@ static struct board_type products[] = { /*define how many times we will try a command because of bus resets */ #define MAX_CMD_RETRIES 3 -#define READ_AHEAD 1024 #define MAX_CTLR 32 /* Originally cciss driver only supports 8 major numbers */ @@ -1402,7 +1401,6 @@ geo_inq: disk->private_data = &h->drv[drv_index]; /* Set up queue information */ - disk->queue->backing_dev_info.ra_pages = READ_AHEAD; blk_queue_bounce_limit(disk->queue, hba[ctlr]->pdev->dma_mask); /* This is a hardware imposed limit. */ @@ -3495,7 +3493,6 @@ static int __devinit cciss_init_one(struct pci_dev *pdev, } drv->queue = q; - q->backing_dev_info.ra_pages = READ_AHEAD; blk_queue_bounce_limit(q, hba[i]->pdev->dma_mask); /* This is a hardware imposed limit. */ -- 2.41.1