Summary

The -Xmaxjitcodesize flag is long overdue for deprecation. It is obsolete on Solaris as far back as 2002, and right now works solely as an alias for -XX:ReservedCodeCacheSize. The flag should be deprecated for removal in JDK 26, obsoleted in JDK 27, and removed in JDK 28.

Problem

We marked -Xmaxjitcodesize obsolete in Solaris as far back as 2002 (JDK 1.4.0). However, at some point the flag was made an alias for -XX:ReservedCodeCacheSize, setting the reserved code cache size in bytes (i.e., the maximum size for the code cache). We currently do not use -Xmaxjitcodesize throughout the JDK codebase and it is long overdue for deprecation. We can remove it without loss of functionality.

Solution

Deprecate -Xmaxjitcodesize for removal in JDK 26, obsolete it in JDK 27, and remove it in JDK 28.

Users of -Xmaxjitcodesize should instead use -XX:ReservedCodeCacheSize.

Specification

if (match_option(option, "-Xmaxjitcodesize", &tail)) {
        warning("Option -Xmaxjitcodesize was deprecated in JDK 26 and will likely be removed in a future release.");
}