Re: [PATCH] trace-cmd: Try alternate path for message cache

[Joel Fernandes <joel@joelfernandes.org>]

On Fri, Apr 01, 2022 at 07:06:29PM -0400, Steven Rostedt wrote:
> On Fri, 1 Apr 2022 15:50:10 -0400
> Joel Fernandes <joel@joelfernandes.org> wrote:
> 
> > export TRACECMD_TEMPDIR="/data"
> > 
> > That’s fair. What about using memfd for this, do you feel that’s
> > reasonable? I have not yet measured how big this file gets but if it’s
> > small enough that might work too.
> 
> Is this a separate question? That is, do you mean using the above
> environment variable *and* then use memfd?
> 
> I believe that the cache is used for passing the compressed data from the
> guest to the host. I don't think it will be more than one compressed chunk.
> 
> But Tzvetomir would know better.

Hey Steve,
No its the same question. Instead of temp file, I was proposing in-memory
file using memfd_create(2), that way no hassle as long as the file is not too
huge.

Also looks like my patch is incomplete anyway, I need to change
tracecmd_msg_handle_cache() as well.

I'll try to write up a patch with memfd unless you guys disagree.

Thanks,

- Joel