关于CMS GC日志理解和CMS full gc的问题

Question

对一个java进程进行分析

# ./jstat -gcnew 32694    
 S0C    S1C    S0U    S1U   TT MTT  DSS      EC       EU     YGC     YGCT  
68096.0 68096.0    0.0 19066.1  6   6 34048.0 545344.0 523400.6     51    2.871

# ./jinfo -flag UseCMSInitiatingOccupancyOnly  32694                           
-XX:-UseCMSInitiatingOccupancyOnly
./jinfo -flag CMSInitiatingOccupancyFraction  32694                      
-XX:CMSInitiatingOccupancyFraction=-1

我截取了一个CMS GC日志片段，如下，其中第一个ParNew回收后新生代还剩余40924K，小于survivor区容量，为何触发了CMS FULL GC? 为何会有“”Allocation Failure“”字样？

64.334: [GC (Allocation Failure) 64.334: [ParNew: 573983K->40924K(613440K), 0.0370301 secs] 592489K->59430K(10417664K), 0.0371384 secs] [Times: user=0.30 sys=0.00, real=0.03 secs]
72.593: [GC (Allocation Failure) 72.593: [ParNew: 586268K->55491K(613440K), 0.0430245 secs] 604774K->79717K(10417664K), 0.0431313 secs] [Times: user=0.41 sys=0.00, real=0.05 secs]
74.635: [GC (CMS Initial Mark) [1 CMS-initial-mark: 24225K(9804224K)] 606596K(10417664K), 0.0619703 secs] [Times: user=0.52 sys=0.00, real=0.06 secs]
74.697: [CMS-concurrent-mark-start]
74.725: [CMS-concurrent-mark: 0.026/0.028 secs] [Times: user=0.15 sys=0.01, real=0.03 secs]
74.725: [CMS-concurrent-preclean-start]
74.749: [CMS-concurrent-preclean: 0.024/0.024 secs] [Times: user=0.12 sys=0.00, real=0.02 secs]
74.749: [CMS-concurrent-abortable-preclean-start]
74.847: [GC (Allocation Failure) 74.847: [ParNew: 600835K->32878K(613440K), 0.0561773 secs] 625061K->78620K(10417664K), 0.0562902 secs] [Times: user=0.44 sys=0.00, real=0.05 secs]
76.120: [CMS-concurrent-abortable-preclean: 1.299/1.371 secs] [Times: user=7.10 sys=0.08, real=1.37 secs]
76.121: [GC (CMS Final Remark) [YG occupancy: 311050 K (613440 K)]76.121: [Rescan (parallel) , 0.0354534 secs]76.156: [weak refs processing, 0.0000496 secs]76.156: [class unloading, 0.0153191 secs]76.172: [scrub symbol table, 0.0086210 secs]76.180: [scrub string table, 0.0018643 secs][1 CMS-remark: 45742K(9804224K)] 356792K(10417664K), 0.0640390 secs] [Times: user=0.43 sys=0.00, real=0.06 secs]
76.185: [CMS-concurrent-sweep-start]
76.209: [CMS-concurrent-sweep: 0.024/0.024 secs] [Times: user=0.12 sys=0.00, real=0.02 secs]
76.209: [CMS-concurrent-reset-start]
76.238: [CMS-concurrent-reset: 0.030/0.030 secs] [Times: user=0.14 sys=0.01, real=0.03 secs]