Re: [PATCH] Add a tracepoint for block request remapping

From: Jun'ichi Nomura
Date: Fri Sep 18 2009 - 13:08:03 EST


Hi Jens, Alasdair,

Jens Axboe wrote:
On Fri, Sep 18 2009, Jun'ichi Nomura wrote:
Since 2.6.31 now has request-based device-mapper, it's useful to have
a tracepoint for request-remapping as well as bio-remapping.

This patch adds a tracepoint for request-remapping, trace_block_rq_remap().
Existing trace_block_remap() is left unchanged but it might be better to
rename it to trace_block_bio_remap().

This looks good, we should definitely have a remap trace at that level
too. Apart from that, nothing further to add than acking the observation
that you need to make the ->device_to part of the trace endian clean.

If you resend with that and just send the core bit (the dm part should
go through the dm branch), then I'll include it for 2.6.32.

I resent a revised patchset but I'm afraid they might be confusing
as the other patchset for max_sectors/queue_limits were also sent
in parallel and I didn't make them look like a thread.
For your reference, these are the revised patchset for tracing request-remap:

[PATCH 1/3] block: Add a tracepoint for block request remapping
https://www.redhat.com/archives/dm-devel/2009-September/msg00201.html

[PATCH 2/3] block: Rename trace_block_remap to trace_block_bio_remap
https://www.redhat.com/archives/dm-devel/2009-September/msg00202.html

[PATCH 3/3] dm: Add a remapping trace to request-based dm
https://www.redhat.com/archives/dm-devel/2009-September/msg00204.html

The 3rd patch for dm depends on the 1st.

--
Jun'ichi Nomura, NEC Corporation
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