JVM 调优 —— 新生代 Survivor 空间不足

先看一段 GC 日志：新生代使用 ParNew。 老年代使用 CMS 

{Heap before GC invocations=0 (full 0):
 par new generation   total 943744K, used 838912K [0x0000000757000000, 0x0000000797000000, 0x0000000797000000)
  eden space 838912K, 100% used [0x0000000757000000, 0x000000078a340000, 0x000000078a340000)
  from space 104832K,   0% used [0x000000078a340000, 0x000000078a340000, 0x00000007909a0000)
  to   space 104832K,   0% used [0x00000007909a0000, 0x00000007909a0000, 0x0000000797000000)
 concurrent mark-sweep generation total 1560576K, used 0K [0x0000000797000000, 0x00000007f6400000, 0x00000007f6400000)
 concurrent-mark-sweep perm gen total 159744K, used 38069K [0x00000007f6400000, 0x0000000800000000, 0x0000000800000000)
2016-01-19T14:15:34.532+0800: 13.812: [GC2016-02-19T14:15:34.532+0800: 13.812: [ParNew
Desired survivor size 53673984 bytes, new threshold 1 (max 6)
- age   1:   55521392 bytes,   55521392 total
: 838912K->54474K(943744K), 0.0914620 secs] 838912K->54474K(2504320K), 0.0916240 secs] [Times: user=0.67 sys=0.06, real=0.09 secs]
Heap after GC invocations=1 (full 0):
 par new generation   total 943744K, used 54474K [0x0000000757000000, 0x0000000797000000, 0x0000000797000000)
  eden space 838912K,   0% used [0x0000000757000000, 0x0000000757000000, 0x000000078a340000)
  from space 104832K,  51% used [0x00000007909a0000, 0x0000000793ed2ae0, 0x0000000797000000)
  to   space 104832K,   0% used [0x000000078a340000, 0x000000078a340000, 0x00000007909a0000)
 concurrent mark-sweep generation total 1560576K, used 0K [0x0000000797000000, 0x00000007f6400000, 0x00000007f6400000)
 concurrent-mark-sweep perm gen total 159744K, used 38069K [0x00000007f6400000, 0x0000000800000000, 0x0000000800000000)
}
{Heap before GC invocations=1 (full 0):
 par new generation   total 943744K, used 893386K [0x0000000757000000, 0x0000000797000000, 0x0000000797000000)
  eden space 838912K, 100% used [0x0000000757000000, 0x000000078a340000, 0x000000078a340000)
  from space 104832K,  51% used [0x00000007909a0000, 0x0000000793ed2ae0, 0x0000000797000000)
  to   space 104832K,   0% used [0x000000078a340000, 0x000000078a340000, 0x00000007909a0000)
 concurrent mark-sweep generation total 1560576K, used 0K [0x0000000797000000, 0x00000007f6400000, 0x00000007f6400000)
 concurrent-mark-sweep perm gen total 159744K, used 53249K [0x00000007f6400000, 0x0000000800000000, 0x0000000800000000)
2016-01-19T14:15:41.943+0800: 21.222: [GC2016-02-19T14:15:41.943+0800: 21.223: [ParNew
Desired survivor size 53673984 bytes, new threshold 1 (max 6)
- age   1:  107256200 bytes,  107256200 total
: 893386K->104832K(943744K), 1.2389070 secs] 893386K->210614K(2504320K), 1.2391870 secs] [Times: user=2.89 sys=0.35, real=1.24 secs]
Heap after GC invocations=2 (full 0):
 par new generation   total 943744K, used 104832K [0x0000000757000000, 0x0000000797000000, 0x0000000797000000)
  eden space 838912K,   0% used [0x0000000757000000, 0x0000000757000000, 0x000000078a340000)
  from space 104832K, 100% used [0x000000078a340000, 0x00000007909a0000, 0x00000007909a0000)
  to   space 104832K,   0% used [0x00000007909a0000, 0x00000007909a0000, 0x0000000797000000)
  concurrent mark-sweep generation total 1560576K, used 105782K [0x0000000797000000, 0x00000007f6400000, 0x00000007f6400000)
 concurrent-mark-sweep perm gen total 159744K, used 53249K [0x00000007f6400000, 0x0000000800000000, 0x0000000800000000)
}