Re: [PATCH] [RFC] block/elevator: change nr_requests handling

2008-01-30 Thread Jens Axboe
On Wed, Jan 30 2008, Nikanth Karthikesan wrote: > On Tue, 2008-01-29 at 19:19 +0100, Jens Axboe wrote: > > On Tue, Jan 29 2008, Nikanth Karthikesan wrote: > > > The /sys/block/whateverdisk/queue/nr_requests is used to limit the > > > number of requests allocated per queue. There can be atmost nr_r

Re: [PATCH] [RFC] block/elevator: change nr_requests handling

2008-01-30 Thread Nikanth Karthikesan
On Tue, 2008-01-29 at 19:19 +0100, Jens Axboe wrote: > On Tue, Jan 29 2008, Nikanth Karthikesan wrote: > > The /sys/block/whateverdisk/queue/nr_requests is used to limit the > > number of requests allocated per queue. There can be atmost nr_requests > > read requests and nr_requests write requests

Re: [PATCH] [RFC] block/elevator: change nr_requests handling

2008-01-29 Thread Jens Axboe
On Tue, Jan 29 2008, Nikanth Karthikesan wrote: > The /sys/block/whateverdisk/queue/nr_requests is used to limit the > number of requests allocated per queue. There can be atmost nr_requests > read requests and nr_requests write requests allocated. > > But this can lead to starvation when there ar

Re: [PATCH] [RFC] block/elevator: change nr_requests handling

2008-01-29 Thread Nikanth Karthikesan
On Tue, 2008-01-29 at 22:59 +0530, Nikanth Karthikesan wrote: > Check for nr_requests only when io schedulers dispatch > > Signed-off-by: Nikanth Karthikesan <[EMAIL PROTECTED]> > Jens, The patch is against 2.6.24. Before the block/ll_rw_blk.c splitup. Thanks Nikanth -- To unsubscribe from t

[PATCH] [RFC] block/elevator: change nr_requests handling

2008-01-29 Thread Nikanth Karthikesan
The /sys/block/whateverdisk/queue/nr_requests is used to limit the number of requests allocated per queue. There can be atmost nr_requests read requests and nr_requests write requests allocated. But this can lead to starvation when there are many tasks doing heavy IO. And the ioc_batching code let