1.错误案例
pfan@ubuntu:~/Downloads$ jmap -heap 3991
Attaching to process ID 3991, please wait...
Error attaching to process: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process
2.解决方案
- 修改/etc/sysctl.d/10-ptrace.conf:
kernel.yama.ptrace_scope = 1
改为
kernel.yama.ptrace_scope = 0
- 重启系统
pfan@ubuntu:~/# reboot
3.成功运行
pfan@ubuntu:~/$ jmap -heap 1567
Attaching to process ID 1567, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 24.60-b09
using thread-local object allocation.
Parallel GC with 4 thread(s)
Heap Configuration:
MinHeapFreeRatio = 0
MaxHeapFreeRatio = 100
MaxHeapSize = 2147483648 (2048.0MB)
NewSize = 1310720 (1.25MB)
MaxNewSize = 17592186044415 MB
OldSize = 5439488 (5.1875MB)
NewRatio = 2
SurvivorRatio = 8
PermSize = 134217728 (128.0MB)
MaxPermSize = 134217728 (128.0MB)
G1HeapRegionSize = 0 (0.0MB)
Heap Usage:
PS Young Generation
Eden Space:
capacity = 698351616 (666.0MB)
used = 394937704 (376.6419448852539MB)
free = 303413912 (289.3580551147461MB)
56.55284457736545% used
From Space:
capacity = 8388608 (8.0MB)
used = 557056 (0.53125MB)
free = 7831552 (7.46875MB)
6.640625% used
To Space:
capacity = 8912896 (8.5MB)
used = 0 (0.0MB)
free = 8912896 (8.5MB)
0.0% used
PS Old Generation
capacity = 1431830528 (1365.5MB)
used = 5558216 (5.300727844238281MB)
free = 1426272312 (1360.1992721557617MB)
0.38818951623861453% used
PS Perm Generation
capacity = 134217728 (128.0MB)
used = 13828272 (13.187667846679688MB)
free = 120389456 (114.81233215332031MB)
10.302865505218506% used