Re: Local DoS through write heavy I/O on CFQ & Deadline

[Chris Friesen]

On 10/18/2012 03:28 PM, Jan Kara wrote:

>    Yeah, ionice has its limitations. The problem is that all buffered
> writes happen just into memory (so completely independently of ionice
> settings). Subsequent writing of dirty memory to disk happens using flusher
> thread which is a kernel process and it doesn't know anything about IO
> priority set for task which created the file. If you wrote the file with
> oflag=direct or oflag=sync you would see that ionice works as expected.

Has anyone looked at storing the ionice value with the buffered write 
request such that the actual writes to disk could be sorted by priority 
and done with the ionice level of the original caller?

Chris
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/