Re: [patch] fixing leaking struct value* in py-value.c

[Tom Tromey <tromey at redhat dot com>]

>>>>> "Aman" == Aman Gupta <themastermind1@gmail.com> writes:

Aman> The gdb process will leak a large amount of memory (>512mb RSS) while
Aman> executing the python loop. Some (but not all) of this memory is
Aman> returned after the loop completes and free_all_values() is called for
Aman> the next command. The following patch against gdb master
Aman> keeps the memory usage constant during the loop.

Thanks for writing this.  It looks reasonable overall.

Do you have a gdb copyright assignment in place?  I can't check, and we
will need one to accept this patch.  If you do not have one, email me
and I will get you started on the process.

Aman> @@ -1062,7 +1081,7 @@ value_to_value_object (struct value *val)
[...]
Aman> -      value_incref (val);
Aman> +      release_value_or_incref (val);

I'm not sure that this is always ok.  I think it depends on the other
callers of release_value, at least.  (There is also some code in gdb
that inspects the value chain, but I think that code can't really
interact with this code.)

A different approach would be to have a wrapper for
value_to_value_object that calls release_value.  Then, we could use this
wrapper whenever we know it is safe -- when the value in question was
created during some computation in the Python layer.

What do you think?

Aman> +int
Aman>  release_value (struct value *val)
[...]
Aman> +  return -1;

It is more idiomatic to "return 1" here.

Tom