外部碎片对WinDbg意味着什么?

时间:2011-11-29 19:46:40

标签: c++ debugging heap windbg

我在处理bad_alloc时遇到问题。它在尝试重新定位和分配2Mb

时在std::vector.push_back期间抛出

堆状态是

  Heap     Flags   Reserv  Commit  Virt   Free  List   UCR  Virt  Lock  Fast 
                    (k)     (k)    (k)     (k) length      blocks cont. heap 
-----------------------------------------------------------------------------
04e00000 00000002   67704  41088  67704  40735   135   135    0     25   LFH
    External fragmentation  99 % (135 free blocks)
    Virtual address fragmentation  39 % (135 uncommited ranges)
...
0c8f0000 00001002   82216  81384  82216   8247 172196    13    5      3   LFH
...

 0: Heap 04e00000
   Flags          00000002 - HEAP_GROWABLE 
   Reserved memory in segments              67704 (k)
   Commited memory in segments              41088 (k)
   Virtual bytes (correction for large UCR) 58644 (k)
   Free space                               40735 (k) (135 blocks)
   External fragmentation          99% (135 free blocks)
   Virtual address fragmentation   29% (135 uncommited ranges)
   Virtual blocks  0 - total 0 KBytes
   Lock contention 37
   Segments        1

   Low fragmentation heap   04e044f0
       Lock contention        0
       Metadata usage         0 bytes
       Statistics:
           Segments created          0
           Segments deleted          0
           Segments reused           0
       Block cache:

       Buckets info:
  Size   Blocks  Seg  Empty  Aff    Distribution
------------------------------------------------
------------------------------------------------

                    Default heap   Front heap       Unused bytes
   Range (bytes)     Busy  Free    Busy   Free     Total  Average 
------------------------------------------------------------------ 
     0 -   1024      217      0      0      0        487      2
  1024 -   2048        1      0      0      0          1      1
  3072 -   4096        0      1      0      0          0      0
 15360 -  16384        1      0      0      0          1      1
203776 - 204800        0      2      0      0          0      0
220160 - 221184        0      2      0      0          0      0
224256 - 225280        0      1      0      0          0      0
236544 - 237568        0      2      0      0          0      0
240640 - 241664        0      1      0      0          0      0
257024 - 258048        0      1      0      0          0      0
265216 - 266240        0      4      0      0          0      0
273408 - 274432        0      1      0      0          0      0
277504 - 278528        0      2      0      0          0      0
281600 - 282624        0      2      0      0          0      0
285696 - 286720        0      6      0      0          0      0
289792 - 290816        0      4      0      0          0      0
293888 - 294912        0     12      0      0          0      0
297984 - 299008        0     10      0      0          0      0
302080 - 303104        0     13      0      0          0      0
306176 - 307200        0     14      0      0          0      0
310272 - 311296        0     19      0      0          0      0
314368 - 315392        0     15      0      0          0      0
318464 - 319488        0      3      0      0          0      0
326656 - 327680        0      1      0      0          0      0
330752 - 331776        0      3      0      0          0      0
333824 - 334848        1      0      0      0          8      8
351232 - 352256        0      1      0      0          0      0
363520 - 364544        0      2      0      0          0      0
367616 - 368640        0      1      0      0          0      0
396288 - 397312        0      3      0      0          0      0
416768 - 417792        0      1      0      0          0      0
420864 - 421888        0      2      0      0          0      0
424960 - 425984        0      1      0      0          0      0
433152 - 434176        0      1      0      0          0      0
437248 - 438272        0      1      0      0          0      0
466944 - 467968        0      1      0      0          0      0
470016 - 471040        0      1      0      0          0      0
482304 - 483328        0      1      0      0          0      0
------------------------------------------------------------------ 
  Total              220    135      0      0        497      2


 0: Heap 0c8f0000
   Flags          00001002 - HEAP_GROWABLE 
   Reserved memory in segments              82216 (k)
   Commited memory in segments              81384 (k)
   Virtual bytes (correction for large UCR) 81620 (k)
   Free space                               8247 (k) (172196 blocks)
   External fragmentation          10% (172196 free blocks)
   Virtual address fragmentation   0% (13 uncommited ranges)
   Virtual blocks  5 - total 0 KBytes
   Lock contention 3
   Segments        1

   Low fragmentation heap   43230048
       Lock contention        0
       Metadata usage      4096 bytes
       Statistics:
           Segments created        120
           Segments deleted          2
           Segments reused           0
       Block cache:
         5:         4096 bytes (    54,     0)
         6:         8192 bytes (    26,     0)
         7:        16384 bytes (    13,     0)
         8:        32768 bytes (     8,     0)
         9:        65536 bytes (     9,     0)
        10:       131072 bytes (     5,     0)
        11:       262144 bytes (     4,     1)

       Buckets info:
  Size   Blocks  Seg  Empty  Aff    Distribution
------------------------------------------------
    64   25483    53      0  0 (53-25483)
    72    2991    30      0  0 (30-2991)
    80     750    15      0  0 (15-750)
    88      46     1      1  0 (1-46)
    96      42     1      1  0 (1-42)
   104      39     1      1  0 (1-39)
   112      36     1      1  0 (1-36)
   120      33     1      1  0 (1-33)
   128      63     1      1  0 (1-63)
   136      60     1      1  0 (1-60)
   144      56     1      1  0 (1-56)
   152      53     1      1  0 (1-53)
   160      51     1      1  0 (1-51)
   168      48     1      1  0 (1-48)
   200      40     1      1  0 (1-40)
   208      39     1      1  0 (1-39)
   224      36     1      1  0 (1-36)
   280      29     1      1  0 (1-29)
   312      26     1      1  0 (1-26)
  7432      17     1      1  0 (1-17)
  9736      26     1      1  0 (1-26)
 10760      24     1      1  0 (1-24)
 11784      22     1      1  0 (1-22)
------------------------------------------------

                    Default heap   Front heap       Unused bytes
   Range (bytes)     Busy  Free    Busy   Free     Total  Average 
------------------------------------------------------------------ 
     0 -   1024   619437 172194  28854   1067   11637848     17
  1024 -   2048       10      1      0      0        113     11
  3072 -   4096        2      0      0      0         32     16
  4096 -   5120        1      0      0      0         16     16
  5120 -   6144        1      0      0      0         20     20
  7168 -   8192        1      0      0     17         20     20
  9216 -  10240        0      0      0     26          0      0
 10240 -  11264        0      0      0     24          0      0
 11264 -  12288        0      0      0     22          0      0
 12288 -  13312        2      0      0      0         32     16
 15360 -  16384        1      0      0      0          1      1
 16384 -  17408        2      0      0      0         32     16
 20480 -  21504        1      0      0      0          8      8
 21504 -  22528        1      0      0      0         20     20
 40960 -  41984        1      0      0      0          8      8
 43008 -  44032        1      0      0      0         16     16
 48128 -  49152        1      0      0      0         16     16
 54272 -  55296        1      0      0      0          8      8
 58368 -  59392        1      0      0      0         17     17
 72704 -  73728        1      0      0      0         20     20
 83968 -  84992        0      1      0      0          0      0
 96256 -  97280        1      0      0      0         16     16
108544 - 109568        1      0      0      0         16     16
116736 - 117760        1      0      0      0         21     21
139264 - 140288        1      0      0      0         16     16
145408 - 146432        1      0      0      0         16     16
159744 - 160768        1      0      0      0         22     22
163840 - 164864        1      0      0      0         20     20
193536 - 194560        1      0      0      0         20     20
262144 - 263168        3      0      0      0         40     13
327680 - 328704        1      0      0      0         16     16
333824 - 334848        1      0      0      0          8      8
436224 - 437248        1      0      0      0         16     16
------------------------------------------------------------------ 
  Total           619479 172196  28854   1156   11638454     17

我的问题是外部碎片99%意味着什么是“堆碎片”而不是“虚拟地址空间碎片”?

“外部碎片”(99%)和“虚拟地址碎片”(29%)有什么区别?

创建新堆可能有帮助吗?

PS:我在同一个进程中有很多托管代码。私人工作组是1,8Gb。

1 个答案:

答案 0 :(得分:2)

基本上,您有大量非常小的对象分配,这会导致碎片。此外,您在同一进程中混合本机代码和托管代码,并且您正在进行大量内存分配。这些方法需要内存管理。最好在进程启动时为大内存分配创建专用堆以避免此类问题。堆只应用于本机代码的大内存分配。

此外,分析托管代码需要如此多内存的原因是个好主意。