爲什麼java程序使用更多的內存比預期

系統的系統信息爲什麼java程序使用更多的內存比預期

OS：的Archlinux

JDK：OpenJDK的（2.4.3的IcedTea）（ArchLinux的建設7.u45_2.4.3-1-x86_64的）

運行應用程序：https://github.com/aemoncannon/ensime

我的Java選項：

-Xms128m -Xmx512M -Xss1M -XX:MaxPermSize=50m 
-XX:MaxDirectMemorySize=10M 
-XX:ReservedCodeCacheSize=64m 
-Dfile.encoding=UTF-8 -XX:NativeMemoryTracking=detai

Linux的頂部命令所示，它採用6.8G * 19.5％= 1.326GB

Natvie存儲器跟蹤顯示它使用713MB

大二哪一個是實際的物理內存使用量，如果它使用1.3GB內存，額外的600 + MB物理內存在哪裏？

頂輸出

top - 09:20:37 up 48 min, 2 users, load average: 0.31, 0.33, 0.36 
Tasks: 161 total, 1 running, 159 sleeping, 0 stopped, 1 zombie 
%Cpu(s): 0.7 us, 0.3 sy, 0.0 ni, 99.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 
KiB Mem: 7091684 total, 4338428 used, 2753256 free, 117044 buffers 
KiB Swap: 8388604 total,  0 used, 8388604 free, 1399904 cached 

    PID USER  PR NI VIRT RES SHR S %CPU %MEM  TIME+ COMMAND 
5666 jilen  20 0 3553516 1.317g 22652 S 0.3 19.5 2:27.72 java

天然存儲器跟蹤outpus（jcmd VM.native_memory細節）

Native Memory Tracking: 

Total: reserved=731125KB, committed=681117KB 

-     Java Heap (reserved=575488KB, committed=574976KB) 
          (mmap: reserved=575488KB, committed=574976KB) 

-      Class (reserved=6388KB, committed=6388KB) 
          (classes #6443) 
          (malloc=6388KB, #16725) 

-     Thread (reserved=27986KB, committed=27986KB) 
          (thread #27) 
          (stack: reserved=27756KB, committed=27756KB) 
          (malloc=82KB, #114) 
          (arena=148KB, #54) 

-      Code (reserved=70523KB, committed=21059KB) 
          (malloc=3963KB, #6149) 
          (mmap: reserved=66560KB, committed=17096KB) 

-      GC (reserved=26964KB, committed=26964KB) 
          (malloc=5900KB, #158) 
          (mmap: reserved=21064KB, committed=21064KB) 

-     Compiler (reserved=176KB, committed=176KB) 
          (malloc=78KB, #238) 
          (arena=98KB, #2) 

-     Internal (reserved=5463KB, committed=5431KB) 
          (malloc=5431KB, #1492) 
          (mmap: reserved=32KB, committed=0KB) 

-     Symbol (reserved=10668KB, committed=10668KB) 
          (malloc=9765KB, #77949) 
          (arena=903KB, #1) 

-   Memory Tracking (reserved=5616KB, committed=5616KB) 
          (malloc=5616KB, #120) 

-  Pooled Free Chunks (reserved=1854KB, committed=1854KB) 
          (malloc=1854KB) 


Virtual memory map: 

[0x00000000dce00000 - 0x0000000100000000] reserved 575488KB for Java Heap 
     from [JVM_handle_linux_signal+0x173dbd] 
    [0x00000000dce00000 - 0x00000000fff80000] committed 574976KB from [JVM_handle_linux_signal+0x650ab] 

[0x00007f53801c7000 - 0x00007f53802c8000] reserved 1028KB for Thread Stack 
     from [JVM_handle_linux_signal+0x12f2ec] 
    [0x00007f53801c7000 - 0x00007f53802c8000] committed 1028KB from [JVM_handle_linux_signal+0x12f2ec] 

[0x00007f5381daf000 - 0x00007f5381eb0000] reserved 1028KB for Thread Stack 
     from [JVM_handle_linux_signal+0x12f2ec] 
    [0x00007f5381daf000 - 0x00007f5381eb0000] committed 1028KB from [JVM_handle_linux_signal+0x12f2ec] 

[0x00007f53821f0000 - 0x00007f53824f3000] reserved 3084KB for Thread Stack 
     from [JVM_handle_linux_signal+0x12f2ec] 
    [0x00007f53821f0000 - 0x00007f53824f3000] committed 3084KB from [JVM_handle_linux_signal+0x12f2ec] 

[0x00007f5382d49000 - 0x00007f5382e4a000] reserved 1028KB for Thread Stack 
     from [JVM_handle_linux_signal+0x12f2ec] 
    [0x00007f5382d49000 - 0x00007f5382e4a000] committed 1028KB from [JVM_handle_linux_signal+0x12f2ec] 

[0x00007f538302a000 - 0x00007f538342e000] reserved 4112KB for Thread Stack 
     from [JVM_handle_linux_signal+0x12f2ec] 
    [0x00007f538302a000 - 0x00007f538342e000] committed 4112KB from [JVM_handle_linux_signal+0x12f2ec] 

[0x00007f53b47c7000 - 0x00007f53b4aca000] reserved 3084KB for Thread Stack 
     from [JVM_handle_linux_signal+0x12f2ec] 
    [0x00007f53b47c7000 - 0x00007f53b4aca000] committed 3084KB from [JVM_handle_linux_signal+0x12f2ec] 

[0x00007f53b4db7000 - 0x00007f53b4eb8000] reserved 1028KB for Thread Stack 
     from [JVM_handle_linux_signal+0x127be9] 
    [0x00007f53b4db7000 - 0x00007f53b4eb8000] committed 1028KB from [JVM_handle_linux_signal+0x127be9] 

[0x00007f53b4eb8000 - 0x00007f53b52bc000] reserved 4112KB for Thread Stack 
     from [JVM_handle_linux_signal+0x12f2ec] 
    [0x00007f53b4eb8000 - 0x00007f53b52bc000] committed 4112KB from [JVM_handle_linux_signal+0x12f2ec] 

[0x00007f53b5894000 - 0x00007f53b5a96000] reserved 2056KB for Thread Stack 
     from [JVM_handle_linux_signal+0x12f2ec] 
    [0x00007f53b5894000 - 0x00007f53b5a96000] committed 2056KB from [JVM_handle_linux_signal+0x12f2ec] 

[0x00007f53b5a96000 - 0x00007f53b5b97000] reserved 1028KB for Thread Stack 
     from [JVM_handle_linux_signal+0x17c90d] 
    [0x00007f53b5a96000 - 0x00007f53b5b97000] committed 1028KB from [JVM_handle_linux_signal+0x17c90d] 

[0x00007f53b5b97000 - 0x00007f53b5c98000] reserved 1028KB for Thread Stack 
     from [JVM_FindSignal+0x118f1b] 
    [0x00007f53b5b97000 - 0x00007f53b5c98000] committed 1028KB from [JVM_FindSignal+0x118f1b] 

[0x00007f53b6e70000 - 0x00007f53b8000000] reserved 17984KB for GC 
     from [JVM_handle_linux_signal+0x172529] 
    [0x00007f53b6e70000 - 0x00007f53b8000000] committed 17984KB from [JVM_handle_linux_signal+0x650ab] 

[0x00007f53c4000000 - 0x00007f53c8000000] reserved 65536KB for Code 
     from [JVM_handle_linux_signal+0x1741a5] 
    [0x00007f53c4000000 - 0x00007f53c5070000] committed 16832KB from [JVM_handle_linux_signal+0x1746f4] 

[0x00007f53cc0e4000 - 0x00007f53cc1fd000] reserved 1124KB for GC 
     from [JVM_handle_linux_signal+0x172529] 
    [0x00007f53cc0e4000 - 0x00007f53cc1fd000] committed 1124KB from [JVM_handle_linux_signal+0x650ab] 

[0x00007f53cc1fd000 - 0x00007f53cc601000] reserved 4112KB for Thread Stack 
     from [AsyncGetCallTrace+0x3949c] 
    [0x00007f53cc1fd000 - 0x00007f53cc601000] committed 4112KB from [AsyncGetCallTrace+0x3949c] 

[0x00007f53cc601000 - 0x00007f53cc71b000] reserved 1128KB for GC 
     from [JVM_handle_linux_signal+0x172529] 
    [0x00007f53cc601000 - 0x00007f53cc71b000] committed 1128KB from [dlerror+0x3aad37] 

[0x00007f53cc71b000 - 0x00007f53cc81b000] reserved 1024KB for Code 
     from [JVM_handle_linux_signal+0x172289] 
    [0x00007f53cc71b000 - 0x00007f53cc75d000] committed 264KB from [JVM_handle_linux_signal+0x1746f4] 

[0x00007f53cf497000 - 0x00007f53cf4a2000] reserved 44KB for GC 
     from [JVM_handle_linux_signal+0x172529] 
    [0x00007f53cf497000 - 0x00007f53cf54d000] committed 728KB from [JVM_handle_linux_signal+0x650ab] 

[0x00007f53cf4a2000 - 0x00007f53cf54d000] reserved 684KB for GC 
     from [JVM_handle_linux_signal+0x172289] 

[0x00007f53cf54d000 - 0x00007f53cf64e000] reserved 1028KB for Thread Stack 
     from [JVM_handle_linux_signal+0x12c997] 
    [0x00007f53cf54d000 - 0x00007f53cf64e000] committed 1028KB from [JVM_handle_linux_signal+0x12c997] 

[0x00007f53cf656000 - 0x00007f53cf66f000] reserved 100KB for GC 
     from [JVM_handle_linux_signal+0x172289] 
    [0x00007f53cf656000 - 0x00007f53cf66f000] committed 100KB from [JVM_handle_linux_signal+0x650ab] 

[0x00007f53cf66f000 - 0x00007f53cf677000] reserved 32KB for Internal 
     from [JVM_handle_linux_signal+0x3c924] 

Details: 

[0x00007f53ce330855] JVM_handle_linux_signal+0xee085 
          (malloc=6627KB #77628) 

[0x00007f53ce291061] JVM_handle_linux_signal+0x4e891 
          (malloc=5120KB #5) 

[0x00007f53ce293021] JVM_handle_linux_signal+0x50851 
          (malloc=5120KB #5) 

[0x00007f53ce2a19b5] JVM_handle_linux_signal+0x5f1e5 
          (malloc=5120KB #5) 

[0x00007f53ce1c8c64] JVM_FindSignal+0x1188f4 
          (malloc=4040KB #1) 

[0x00007f53cde99851] dlerror+0x409851 
          (malloc=3903KB #5678) 

[0x00007f53cdd2dcb3] dlerror+0x29dcb3 
          (malloc=2643KB #148) 

[0x00007f53cdff5b86] AsyncGetCallTrace+0x6dc46 
          (malloc=2512KB #314) 

[0x00007f53ce1c0b17] JVM_FindSignal+0x1107a7 
          (malloc=1274KB #106) 

[0x00007f53ce291149] JVM_handle_linux_signal+0x4e979 
          (malloc=640KB #5) 

[0x00007f53ce233375] JVM_FindSignal+0x183005 
          (malloc=524KB #419) 

[0x00007f53ce38c670] JVM_handle_linux_signal+0x149ea0 
          (malloc=469KB #1) 

[0x00007f53cde87c53] dlerror+0x3f7c53 
          (malloc=408KB #16085) 

[0x00007f53cdd2d142] dlerror+0x29d142 
          (malloc=360KB #1) 

[0x00007f53cdff5186] AsyncGetCallTrace+0x6d246 
          (malloc=310KB #25) 

[0x00007f53ce38c581] JVM_handle_linux_signal+0x149db1 
          (malloc=156KB #1) 

[0x00007f53cdd38523] dlerror+0x2a8523 
          (malloc=127KB #681) 

[0x00007f53ce1c5acb] JVM_FindSignal+0x11575b 
          (malloc=96KB #2) 

[0x00007f53ce1c807e] JVM_FindSignal+0x117d0e 
          (malloc=96KB #1) 

[0x00007f53ce38e0e4] JVM_handle_linux_signal+0x14b914 
          (malloc=80KB #5) 

[0x00007f53ce368abd] JVM_handle_linux_signal+0x1262ed 
          (malloc=71KB #25) 

[0x00007f53ce1b4c27] JVM_FindSignal+0x1048b7 
          (malloc=64KB #16) 

[0x00007f53ce1b4c97] JVM_FindSignal+0x104927 
          (malloc=64KB #16) 

[0x00007f53ce25c867] JVM_handle_linux_signal+0x1a097 
          (malloc=55KB #116) 

[0x00007f53ce1c0584] JVM_FindSignal+0x110214 
          (malloc=51KB #1) 

[0x00007f53ce1c5a15] JVM_FindSignal+0x1156a5 
          (malloc=48KB #1) 

[0x00007f53cdea0fc3] dlerror+0x410fc3 
          (malloc=37KB #464) 

[0x00007f53cdf169bd] dlerror+0x4869bd 
          (malloc=36KB #13) 

[0x00007f53ce3b2aa7] JVM_handle_linux_signal+0x1702d7 
          (malloc=24KB #13) 

[0x00007f53cdff6496] AsyncGetCallTrace+0x6e556 
          (malloc=20KB #4) 

[0x00007f53cdeb2ff3] dlerror+0x422ff3 
          (malloc=17KB #180) 

[0x00007f53ce27ba1b] JVM_handle_linux_signal+0x3924b 
          (malloc=15KB #255) 

[0x00007f53ce368b9d] JVM_handle_linux_signal+0x1263cd 
          (malloc=10KB #1) 

[0x00007f53ce367fdb] JVM_handle_linux_signal+0x12580b 
          (malloc=8KB #47) 

[0x00007f53cdff2df5] AsyncGetCallTrace+0x6aeb5 
          (malloc=8KB #11) 

[0x00007f53cdf5d7d4] dlerror+0x4cd7d4 
          (malloc=8KB #1) 

[0x00007f53ce289bc4] JVM_handle_linux_signal+0x473f4 
          (malloc=8KB #1) 

[0x00007f53ce2059d6] JVM_FindSignal+0x155666 
          (malloc=7KB #62) 

[0x00007f53ce27bb04] JVM_handle_linux_signal+0x39334 
          (malloc=7KB #251) 

[0x00007f53ce242453] fork1+0x52b3 
          (malloc=6KB #28) 

[0x00007f53ce024918] AsyncGetCallTrace+0x9c9d8 
          (malloc=5KB #18) 

[0x00007f53cdd2d333] dlerror+0x29d333 
          (malloc=2KB #57) 

[0x00007f53ce36a598] JVM_handle_linux_signal+0x127dc8 
          (malloc=2KB #1) 

[0x00007f53ce2d6e24] JVM_handle_linux_signal+0x94654 
          (malloc=2KB #1) 

[0x00007f53ce290d96] JVM_handle_linux_signal+0x4e5c6 
          (malloc=2KB #5) 

[0x00007f53ce2a1536] JVM_handle_linux_signal+0x5ed66 
          (malloc=2KB #5) 

[0x00007f53ce25a49b] JVM_handle_linux_signal+0x17ccb 
          (malloc=2KB #7) 

[0x00007f53cde881eb] dlerror+0x3f81eb 
          (malloc=1KB #15) 

[0x00007f53ce171720] JVM_FindSignal+0xc13b0 
          (malloc=1KB #74) 

[0x00007f53cdf5ef54] dlerror+0x4cef54 
          (malloc=1KB #1) 

[0x00007f53cde8a8aa] dlerror+0x3fa8aa 
          (malloc=1KB #59) 

[0x00007f53ce3b658d] JVM_handle_linux_signal+0x173dbd 
          (mmap: reserved=575488KB, committed=574976KB) 

[0x00007f53ce3b6975] JVM_handle_linux_signal+0x1741a5 
          (mmap: reserved=65536KB, committed=16832KB) 

[0x00007f53ce3b4cf9] JVM_handle_linux_signal+0x172529 
          (mmap: reserved=20280KB, committed=20280KB) 

[0x00007f53ce371abc] JVM_handle_linux_signal+0x12f2ec 
          (mmap: reserved=19532KB, committed=19532KB) 

[0x00007f53cdfc13dc] AsyncGetCallTrace+0x3949c 
          (mmap: reserved=4112KB, committed=4112KB) 

[0x00007f53ce3b4a59] JVM_handle_linux_signal+0x172289 
          (mmap: reserved=1808KB, committed=1048KB) 

[0x00007f53ce1c928b] JVM_FindSignal+0x118f1b 
          (mmap: reserved=1028KB, committed=1028KB) 

[0x00007f53ce36a3b9] JVM_handle_linux_signal+0x127be9 
          (mmap: reserved=1028KB, committed=1028KB) 

[0x00007f53ce36f167] JVM_handle_linux_signal+0x12c997 
          (mmap: reserved=1028KB, committed=1028KB) 

[0x00007f53ce3bf0dd] JVM_handle_linux_signal+0x17c90d 
          (mmap: reserved=1028KB, committed=1028KB) 

[0x00007f53ce27f0f4] JVM_handle_linux_signal+0x3c924 
          (mmap: reserved=32KB, committed=0KB)

來源

2013-11-27 jilen

本機內存跟蹤跟蹤使用虛擬內存。 RES和％MEM跟蹤物理內存的使用。這兩者幾乎沒有任何關係。實際內存使用情況的答案取決於「內存使用情況」是指物理內存使用情況還是虛擬內存使用情況。 –

@DavidSchwartz我的意思是物理內存的使用，對不起！ – jilen

的RES或％MEM值的物理存儲器中的實際使用情況。

因爲您的系統完全沒有內存壓力，所以不會嘗試恢復物理內存。這是因爲這樣的努力是一個失敗的主張。如果內存不會很快用於其他目的，那麼免費的努力就會被浪費掉。如果內存很快用於其他目的，那麼努力使內存免於浪費，必須重新使用內存。當需要內存時，現代操作系統直接將內存從一種用途轉換到另一種用途，而無需使內存自由。只有在沒有其他選擇的情況下，內存纔會被釋放。

所以，基本上，物理內存暫時被浪費，直到系統可以找到一些更好的使用它。如果您在計算機上運行一些消耗物理內存的其他任務，則會在物理內存轉換爲其他用途時看到RES和％MEM值下降。

來源

2013-11-27 01:50:31

但是我已經設置了Xmx和DirectMemorySize，爲什麼該進程使用的次數是我設置的兩倍多 – jilen

那些控制虛擬內存的使用量，而不是物理內存。它們對物理內存使用有間接影響，但不直接控制它。你的操作系統正在變得聰明，而不是毫無意義的努力。把它置於一定的記憶壓力下，觀察居民收縮。 –

你的意思是這些內存中的某些實際上是「免費」的，但並未被系統撤銷？ – jilen

爲什麼java程序使用更多的內存比預期

回答

相關問題