review(S): 7036236: VM crashes assert((!inside_attrs()) || is_error_reported()) failed ...

[Igor Veresov]

[resending]

Assert is caused by a race: CompileBroker::handle_full_code_cache() can 
be called in different contexts, so a lock is required when we're 
printing to xtty, since it's stateful. So I put the xml element 
construction under a tty lock.

However, CodeCache::log_state() calls largest_free_block() that will 
unlock the tty lock, which will cause tearing and the same assertion 
failure (this will also happen in NMethodSweeper::log_sweep()). To 
alleviate this problem I moved the call to log_state() before the tty 
lock is taken and made it do the output to a stringStream, which is 
printed later under the tty lock. This way we decouple the tty lock and 
CodeCache_lock in largest_free_block().

Also removed ttyUnlocker from largest_free_block(), since it's no longer 
needed.

Webrev: http://cr.openjdk.java.net/~iveresov/7036236/webrev.00/

Thanks!
igor