Messages in this thread | | | Date | Wed, 10 Oct 2012 10:22:18 -0400 | From | Vivek Goyal <> | Subject | Re: [PATCH V3] block/throttle: Add IO throttled information in blkio.throttle |
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On Tue, Oct 09, 2012 at 02:53:45PM +0800, Robin Dong wrote: > From: Robin Dong <sanbai@taobao.com> > > Currently, if the IO is throttled by io-throttle, the SA has no idea of > the situation and can't report it to the real application user about > that he/she has to do something. So this patch adds a new interface > named blkio.throttle.io_queued which indicates how many IOs are > currently throttled. > > The nr_queued[] of struct throtl_grp is of type "unsigned int" and updates > to it are atomic both at 32bit and 64bit platforms, so we could just > read tg->nr_queued only under blkcg->lock. > > Changelog from v2: > Use nr-queued[] of struct throtl_grp for stats instaed of adding new blkg_rwstat. > > Cc: Tejun Heo <tj@kernel.org> > Cc: Vivek Goyal <vgoyal@redhat.com> > Cc: Jens Axboe <axboe@kernel.dk> > Signed-off-by: Tao Ma <boyu.mt@taobao.com> > Signed-off-by: Robin Dong <sanbai@taobao.com> > --- > block/blk-throttle.c | 40 ++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 40 insertions(+), 0 deletions(-) > > diff --git a/block/blk-throttle.c b/block/blk-throttle.c > index a9664fa..e410448 100644 > --- a/block/blk-throttle.c > +++ b/block/blk-throttle.c > @@ -953,6 +953,32 @@ static u64 tg_prfill_cpu_rwstat(struct seq_file *sf, > return __blkg_prfill_rwstat(sf, pd, &rwstat); > } > > +static u64 tg_prfill_io_queued(struct seq_file *sf, > + struct blkg_policy_data *pd, int off) > +{ > + static const char *rwstr[] = { > + [READ] = "Read", > + [WRITE] = "Write", > + }; > + struct throtl_grp *tg = pd_to_tg(pd); > + const char *dname = NULL; > + unsigned int v; > + int i; > + > + if (pd->blkg->q->backing_dev_info.dev) > + dname = dev_name(pd->blkg->q->backing_dev_info.dev); > + > + if (!dname) > + return 0; > + > + for (i = 0; i <= WRITE; i++) > + seq_printf(sf, "%s %s %u\n", dname, rwstr[i], tg->nr_queued[i]);
You are printing only READ/WRITE stats and not the SYNC/ASYNC stats. This is not inline with rest of the stats like throttle.io_serviced and throttle.io_service_bytes.
I guess it is better to maintain rwstat for io_queued and display it according to io_serviced.
Thanks Vivek
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