Messages in this thread | | | Subject | Re: RFC - how to balance Dirty+Writeback in the face of slow writeback. | From | Trond Myklebust <> | Date | Thu, 17 Aug 2006 08:36:19 -0400 |
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On Wed, 2006-08-16 at 23:14 -0700, Andrew Morton wrote: > btw, one thing which afaik NFS _still_ doesn't do is to wake up processes > which are stuck in blk_congestion_wait() when NFS has retired a bunch of > writes. It should do so, otherwise NFS write-intensive workloads might end > up sleeping for too long. I guess the amount of buffering and hysteresis > we have in there has thus far prevented any problems from being observed.
Are we to understand it that you consider blk_congestion_wait() to be an official API, and not just another block layer hack inside the VM?
'cos currently the only tools for waking up processes in blk_congestion_wait() are the two routines:
static void clear_queue_congested(request_queue_t *q, int rw) and static void set_queue_congested(request_queue_t *q, int rw)
in block/ll_rw_blk.c. Hardly a model of well thought out code...
Trond
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