Re: RFC - how to balance Dirty+Writeback in the face of slow writeback.

Trond Myklebust
2006-08-17T16:23:21Z

On Thu, 2006-08-17 at 08:14 -0700, Andrew Morton wrote:
> Take a look at blk_congestion_wait(). It doesn't know about request
> queues. We'd need a new
>
> void writeback_congestion_end(int rw)
> {
> wake_up(congestion_wqh[rw]);
> }
>
> or similar.

...and how often do you want us to call this? NFS doesn't know much
about request queues either: it writes out pages on a per-RPC call
basis. In the worst case that could mean waking up the VM every time we
write out a single page.

Cheers,
Trond