can not limit ram cache

[yonghao@cache177 ~]$ links -dump http://localhost:8080/stat/ | grep ram
 proxy.config.cache.ram_cache.size=10737418240
 proxy.config.cache.ram_cache_cutoff=131072
 proxy.config.cache.ram_cache.algorithm=1
 proxy.config.cache.ram_cache.compress=0
 proxy.config.cache.ram_cache.ssd_percent=25
 proxy.config.cache.ram_cache.compress_percent=90
 proxy.process.cache.ram_cache.total_bytes=12884901886
 proxy.process.cache.volume_0.ram_cache.total_bytes=-73014444066
 proxy.process.cache.ram_cache.bytes_used=11840122880