Re: blk_classic tracing horribly broken

From: Christoph Hellwig
Date: Thu Sep 22 2011 - 14:12:23 EST


On Thu, Sep 22, 2011 at 01:57:11PM -0400, Jeff Moyer wrote:
> Hi,
>
> I've stared at the code for a while, and I've come up empty. Would
> anyone care to take a stab at fixing this?
>
> To reproduce:
>
> mount -t debugfs none /sys/kernel/debug
> cd /sys/kernel/debug/tracing
> echo blk > current_tracer
> echo 1 > events/block/enable
> echo 1 > options/blk_classic
> echo 1 > tracing_on
>
> dd if=/dev/<device> of=/dev/null bs=1M count=1 iflag=direct
> cat trace

Why are you using this interface anyway? We actually had planned to
drop it long time ago, but for some reason that never happened.

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