Currently, the code calculates the buffer size in the case of c2_only the same way as it would with tiered compilation.
This was reported with a proposed fix (reverse hunk of https://github.com/openjdk/jdk/pull/24972/commits/c43b18a6681acb541be1b3bdadbd635070a2d58d) by [~shade].
This was reported with a proposed fix (reverse hunk of https://github.com/openjdk/jdk/pull/24972/commits/c43b18a6681acb541be1b3bdadbd635070a2d58d) by [~shade].