Add note about how shared_pool_max works.
Add note about how shared_pool_max works.

buaasun/grappa,buaasun/grappa,buaasun/grappa,alexfrolov/grappa,buaasun/grappa,alexfrolov/grappa,uwsampa/grappa,buaasun/grappa,uwsampa/grappa,buaasun/grappa,alexfrolov/grappa,uwsampa/grappa,uwsampa/grappa,buaasun/grappa,alexfrolov/grappa,alexfrolov/grappa,uwsampa/grappa,uwsampa/grappa,alexfrolov/grappa,uwsampa/grappa,alexfrolov/grappa