Re: [PATCH] trace_seq: Increase the buffer size to almost two pages

[Steven Rostedt]

On Mon, 11 Dec 2023 21:46:27 +0900
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> wrote:

> > 
> > By increasing the trace_seq buffer to almost two pages, it can now print
> > out the first line.
> > 
> > This also subtracts the rest of the trace_seq fields from the buffer, so
> > that the entire trace_seq is now PAGE_SIZE aligned.  
> 
> Ok, but I just a bit concern about the memory consumption.
> Since this is very specific case, can we make it configurable later?

I was concerned about this too, but it looks like it's allocated and later
freed in every location except for a couple of instances.

One is "tracepoint_print_iter" which is used to pipe tracepoints to printk.
I think we can possibly make that allocated too.

The other is in ftrace_dump, which I don't think we can easily allocate
that. Although, we could have it allocated at boot up if
ftrace_dump_on_oops() is enabled.

Another KTODO?

> 
> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> 

Thanks!

-- Steve