On Fri, 19 May 2006 10:00:38 -0500 James Bottomley wrote:
> This is the wrong thing to do. You'll force all allocations for this
> device to go through ZONE_DMA, which is a horrifically constrained
> resource at 16MB. If it can take anything in lowmem because the driver
> is unconverted, then you want it to specify BLK_BOUNCE_HIGH as the queue
> limit.
OK, I think I have ppa like imm now.
From: Randy Dunlap <rdunlap@xxxxxxxxxxxx>
ppa cannot handle highmem pages, and like imm, which already has
this patch, the device is slow, so performance is not a big issue,
so just force pages to be in low memory (hence mapped).
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxx>
---
drivers/scsi/ppa.c | 11 +++++++++++
1 files changed, 11 insertions(+)
--- linux-2.6.17-rc4.orig/drivers/scsi/ppa.c
+++ linux-2.6.17-rc4/drivers/scsi/ppa.c
@@ -982,6 +982,12 @@ static int device_check(ppa_struct *dev)
return -ENODEV;
}
+static int ppa_adjust_queue(struct scsi_device *device)
+{
+ blk_queue_bounce_limit(device->request_queue, BLK_BOUNCE_HIGH);
+ return 0;
+}
+
static struct scsi_host_template ppa_template = {
.module = THIS_MODULE,
.proc_name = "ppa",
@@ -997,6 +1003,11 @@ static struct scsi_host_template ppa_tem
.cmd_per_lun = 1,
.use_clustering = ENABLE_CLUSTERING,
.can_queue = 1,
+ .slave_alloc = ppa_adjust_queue,
+ .unchecked_isa_dma = 1, /* ppa cannot deal with highmem, so
+ * this is an easy trick to ensure
+ * all io pages for this host reside
+ * in low memory */
};
/***************************************************************************
---
-
: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
