On 08/31/2015 07:05 PM, Vivek Goyal wrote:
On Mon, Aug 31, 2015 at 02:24:36PM -0700, Andy Grover wrote:
This enables runtime modification of the read and write delay values.
Make sure if the delay time is reduced to flush currently-delayed
bios first, to maintain ordering.
Signed-off-by: Andy Grover <agrover@xxxxxxxxxx>
---
Documentation/device-mapper/delay.txt | 8 +++++++
drivers/md/dm-delay.c | 42 +++++++++++++++++++++++++++++++++++
2 files changed, 50 insertions(+)
diff --git a/Documentation/device-mapper/delay.txt b/Documentation/device-mapper/delay.txt
index 15adc55..9e80751 100644
--- a/Documentation/device-mapper/delay.txt
+++ b/Documentation/device-mapper/delay.txt
@@ -10,6 +10,14 @@ Parameters:
With separate write parameters, the first set is only used for reads.
Delays are specified in milliseconds.
+Message Interface
+-----------------
+The delay target will accept a message of the following format:
+
+set_delay <read_delay> [<write_delay>]
+
Hi Andy,
So if I want to change only write_delay and keep read_delay same, how do
I do that. Do I have to keep track of existing delay values in user space
and pass same value in read_delay to achieve this.
Thanks
Vivek
Hi Vivek,
Yes I suppose userspace would either need to remember read_delay so as
to not change it while setting write_delay, or I guess it could read the
existing values by getting table status before sending the message. Is
this reasonable, or do you think it would be better to, say, have
separate messages for setting the two values, or some other message style?
Thanks -- Regards -- Andy
--
dm-devel mailing list
dm-devel@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/dm-devel
