From: Fengguang Wu <fengguang.wu@intel.com>
To: Jan Kara <jack@suse.cz>
Cc: Tejun Heo <tj@kernel.org>, Jens Axboe <axboe@kernel.dk>,
linux-kernel@vger.kernel.org, chavey@google.com
Subject: Re: [PATCH v2] writeback: mark sysctl vm.block_dump for removal
Date: Wed, 16 Jan 2013 10:53:26 +0800 [thread overview]
Message-ID: <20130116025326.GB10000@localhost> (raw)
In-Reply-To: <20130116020753.GB25806@quack.suse.cz>
On Wed, Jan 16, 2013 at 03:07:53AM +0100, Jan Kara wrote:
> On Tue 15-01-13 08:28:13, Tejun Heo wrote:
> > vm.block_dump is nasty in that it dumps IO traces directly to printk.
> > It isn't scalable and can easily lead to looping behavior - IO
> > generating kernel message which in turn genreates log IO, ad
> > infinitum.
> >
> > Now that proper tracepoints are in place, vm.block_dump isn't
> > necessary. Generate a warning if used so that it can be removed down
> > the road.
> > + if (!warned && block_dump) {
> > + pr_warning("sysctl: vm.block_dump is scheduled for removal. Use tracepoints instead.\n");
> > + pr_warning("sysctl: Please contact Jens Axboe <axboe@kernel.dk> if you require this.\n");
> > + warned = true;
Looks good to me. A warning in dmesg is pertinent because the
block_dump users will be looking at dmesg for block dump results.
Hmm, perhaps a more practical tip on the usage of replacement
tracepoints or tool will help eliminate some user emails to Jens.
> > diff --git a/patches/series b/patches/series
> > index 9fb9bfe..b2582cb 100644
> > --- a/patches/series
> > +++ b/patches/series
> > @@ -18,3 +18,4 @@ kill-pool-gcwq
> > remove-gcwq
> > rename-nr_running
> > cleanup-leftovers
> > +dbg
An extra chunk.
Reviewed-by: Fengguang Wu <fengguang.wu@intel.com>
Thanks!
prev parent reply other threads:[~2013-01-16 2:53 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-11 21:06 [PATCHSET] block: improve tracepoints, take#2 Tejun Heo
2013-01-11 21:06 ` [PATCH 1/5] block: add missing block_bio_complete() tracepoint Tejun Heo
2013-01-11 21:06 ` [PATCH 2/5] block: add @req to bio_{front|back}_merge tracepoints Tejun Heo
2013-01-11 21:06 ` [PATCH 3/5] buffer: make touch_buffer() an exported function Tejun Heo
2013-01-11 21:06 ` [PATCH 4/5] block: add block_{touch|dirty}_buffer tracepoint Tejun Heo
2013-01-11 21:06 ` [PATCH 5/5] writeback: add more tracepoints Tejun Heo
2013-01-12 3:17 ` Fengguang Wu
2013-01-14 13:57 ` Jan Kara
2013-01-14 14:02 ` [PATCHSET] block: improve tracepoints, take#2 Jens Axboe
2013-01-14 17:43 ` Tejun Heo
2013-01-14 18:22 ` [PATCH] writeback: mark sysctl vm.block_dump for removal Tejun Heo
2013-01-14 19:00 ` Jan Kara
2013-01-15 16:28 ` [PATCH v2] " Tejun Heo
2013-01-16 2:07 ` Jan Kara
2013-01-16 2:53 ` Fengguang Wu [this message]
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