On 10/21/2018 9:16 AM, Sai Prakash Ranjan wrote:

On 10/20/2018 9:57 PM, Joel Fernandes wrote:

quoted

On Sat, Oct 20, 2018 at 12:02:37PM +0530, Sai Prakash Ranjan wrote:

quoted

On 10/20/2018 10:55 AM, Joel Fernandes wrote:

quoted

On Sun, Sep 09, 2018 at 01:57:01AM +0530, Sai Prakash Ranjan wrote:

quoted

Hi,

This patch series adds Event tracing support to pstore and is 
continuation
to the RFC patch introduced to add a new tracing facility for register
accesses called Register Trace Buffer(RTB). Since we decided to not 
introduce
a separate framework to trace register accesses and use existing 
framework
like tracepoints, I have moved from RFC. Details of the RFC in link 
below:

Link: 
https://lore.kernel.org/lkml/cover.1535119710.git.saiprakash.ranjan@codeaurora.org/ (local) 


MSR tracing example given by Steven was helpful in using 
tracepoints for
register accesses instead of using separate trace. But just having 
these
IO traces would not help much unless we could have them in some 
persistent
ram buffer for debugging unclocked access or some kind of bus hang 
or an
unexpected reset caused by some buggy driver which happens a lot 
during
initial development stages. By analyzing the last few entries of 
this buffer,
we could identify the register access which is causing the issue.

Hi Sai,

I wanted to see if I could make some time to get your patches 
working. We are
hitting usecases that need something like this as well. Basically 
devices
hanging and then the ramdump does not tell us much, so in this case 
pstore
events can be really helpful. This usecase came up last year as well.

Anyway while I was going through your patches, I cleaned up some 
pstore code
as well and I have 3 more patches on top of yours for this clean up. 
I prefer
we submit the patches together and sync our work together so that 
there is
least conflict.

Here's my latest tree:
https://github.com/joelagnel/linux-kernel/commits/pstore-events
(note that I have only build tested the patches since I just wrote 
them and
its quite late in the night here ;-))

Hi Joel,

Thanks for looking into this. Sure, I will be happy to sync up with 
you on

Thanks. And added a fourth patch in the tree too.

quoted

this. I can test your additional patches on top of my pstore patches. 
BTW,
I'm still stuck at copying binary record into pstore and then extract it
during read time. Seems like I'm missing something.

Sure, push your latest somewhere and let me know. I'll try to get you 
unstuck.

Thanks Joel, I will push my changes and let you know in some time.

Hi Joel,

Here's my tree:
https://github.com/saiprakash-ranjan/linux/commits/pstore-events

I have one patch extra on top of your patches. Nothing much on binary 
record storage in this patch, only removed kmalloc in pstore event call 
to avoid loop.

Thanks,
Sai
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