问题描述
我试图了解！地址摘要报告是如何管理分配的。我有以下代码来尝试测试它。我基本上更改了数组的大小，然后附加了winbg来检查结果！地址摘要
static void Main(string[] args)
{
int size = 2000;
var something = new byte[size];
for (int i = 0; i < something.Length; i++)
{
something[i] = 10;
}
Console.WriteLine("Attach Windbg now");
Console.Read();
// not sure if its needed but have it so that this object is still referenced and optimizations don't remove it proactively
for (int i = 0; i < something.Length; i++)
{
Console.WriteLine(something[i]);
}
}
大小=50000
--- Usage Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal
Free 53 7fff`e1546000 ( 128.000 Tb) 100.00%
<unknown> 61 0`18a1d000 ( 394.113 Mb) 80.32% 0.00%
Image 163 0`031da000 ( 49.852 Mb) 10.16% 0.00%
MappedFile 12 0`019f8000 ( 25.969 Mb) 5.29% 0.00%
Stack 12 0`01000000 ( 16.000 Mb) 3.26% 0.00%
Heap 22 0`002f3000 ( 2.949 Mb) 0.60% 0.00%
Other 8 0`001bf000 ( 1.746 Mb) 0.36% 0.00%
TEB 4 0`00008000 ( 32.000 kb) 0.01% 0.00%
PEB 1 0`00001000 ( 4.000 kb) 0.00% 0.00%
--- Type Summary (for busy) ------ RgnCount ----------- Total Size -------- %ofBusy %ofTotal
MEM_PRIVATE 101 0`19d0b000 ( 413.043 Mb) 84.18% 0.00%
MEM_IMAGE 163 0`031da000 ( 49.852 Mb) 10.16% 0.00%
MEM_MAPPED 19 0`01bc5000 ( 27.770 Mb) 5.66% 0.00%
--- State Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal
MEM_FREE 53 7fff`e1546000 ( 128.000 Tb) 100.00%
MEM_RESERVE 51 0`1aec5000 ( 430.770 Mb) 87.79% 0.00%
MEM_COMMIT 232 0`03be5000 ( 59.895 Mb) 12.21% 0.00%
--- Protect Summary (for commit) - RgnCount ----------- Total Size -------- %ofBusy %ofTotal
PAGE_EXECUTE_READ 24 0`0262d000 ( 38.176 Mb) 7.78% 0.00%
PAGE_READONLY 71 0`00dfb000 ( 13.980 Mb) 2.85% 0.00%
PAGE_WRITECOPY 31 0`00417000 ( 4.090 Mb) 0.83% 0.00%
PAGE_READWRITE 81 0`00335000 ( 3.207 Mb) 0.65% 0.00%
PAGE_EXECUTE_WRITECOPY 3 0`00043000 ( 268.000 kb) 0.05% 0.00%
PAGE_EXECUTE_READWRITE 15 0`00016000 ( 88.000 kb) 0.02% 0.00%
PAGE_READWRITE|PAGE_GUARD 5 0`00015000 ( 84.000 kb) 0.02% 0.00%
PAGE_EXECUTE 2 0`00003000 ( 12.000 kb) 0.00% 0.00%
--- Largest Region by Usage ----------- Base Address -------- Region Size ----------
Free 0`7fff0000 7ff5`7f760000 ( 127.959 Tb)
<unknown> 0`02e62000 0`0ffde000 ( 255.867 Mb)
Image 7ffd`0ab5d000 0`010e4000 ( 16.891 Mb)
MappedFile 0`0150c000 0`01234000 ( 18.203 Mb)
Stack 0`1ba90000 0`003f9000 ( 3.973 Mb)
Heap 0`02741000 0`00101000 ( 1.004 Mb)
Other 0`011b0000 0`00181000 ( 1.504 Mb)
TEB 7ff5`ff928000 0`00002000 ( 8.000 kb)
PEB 7ff5`ff926000 0`00001000 ( 4.000 kb)
这是它在！Dumpheap-stat输出中的外观
00007ffd0ad95740 4 50609 System.Byte[]
这是它在！EEHeap-GC输出中的外观
Number of GC Heaps: 1
generation 0 starts at 0x0000000002ec1030
generation 1 starts at 0x0000000002ec1018
generation 2 starts at 0x0000000002ec1000
ephemeral segment allocation context: ephemeral segment allocation context: none
none
segment begin allocated size
0000000002ec0000 0000000002ec1000 0000000002ed3fe8 0x12fe8(77800)
Large object heap starts at 0x0000000012ec1000
segment begin allocated size
0000000012ec0000 0000000012ec1000 0000000012ec9720 0x8720(34592)
Total Size: Total Size: Size: 0x1b708 (112392) bytesSize: 0x1b708 (112392) bytes.
.
------------------------------
------------------------------
GC Heap Size: GC Heap Size: Size: 0x1b708 (112392) bytesSize: 0x1b708 (112392) bytes.
，大小=2000
0:003> !address -summary
Mapping file section regions...
Mapping module regions...
Mapping PEB regions...
Mapping TEB and stack regions...
Mapping heap regions...
Mapping page heap regions...
Mapping other regions...
Mapping stack trace database regions...
Mapping activation context regions...
--- Usage Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal
Free 50 7fff`e1941000 ( 128.000 Tb) 100.00%
<unknown> 57 0`1861b000 ( 390.105 Mb) 80.16% 0.00%
Image 163 0`031da000 ( 49.852 Mb) 10.24% 0.00%
MappedFile 12 0`019f8000 ( 25.969 Mb) 5.34% 0.00%
Stack 12 0`01000000 ( 16.000 Mb) 3.29% 0.00%
Heap 22 0`002fa000 ( 2.977 Mb) 0.61% 0.00%
Other 8 0`001bf000 ( 1.746 Mb) 0.36% 0.00%
TEB 4 0`00008000 ( 32.000 kb) 0.01% 0.00%
PEB 1 0`00001000 ( 4.000 kb) 0.00% 0.00%
--- Type Summary (for busy) ------ RgnCount ----------- Total Size -------- %ofBusy %ofTotal
MEM_PRIVATE 97 0`19910000 ( 409.063 Mb) 84.05% 0.00%
MEM_IMAGE 163 0`031da000 ( 49.852 Mb) 10.24% 0.00%
MEM_MAPPED 19 0`01bc5000 ( 27.770 Mb) 5.71% 0.00%
--- State Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal
MEM_FREE 50 7fff`e1941000 ( 128.000 Tb) 100.00%
MEM_RESERVE 50 0`1aadc000 ( 426.859 Mb) 87.71% 0.00%
MEM_COMMIT 229 0`03bd3000 ( 59.824 Mb) 12.29% 0.00%
--- Protect Summary (for commit) - RgnCount ----------- Total Size -------- %ofBusy %ofTotal
PAGE_EXECUTE_READ 24 0`0262d000 ( 38.176 Mb) 7.84% 0.00%
PAGE_READONLY 71 0`00dfb000 ( 13.980 Mb) 2.87% 0.00%
PAGE_WRITECOPY 31 0`00417000 ( 4.090 Mb) 0.84% 0.00%
PAGE_READWRITE 79 0`00326000 ( 3.148 Mb) 0.65% 0.00%
PAGE_EXECUTE_WRITECOPY 3 0`00043000 ( 268.000 kb) 0.05% 0.00%
PAGE_EXECUTE_READWRITE 15 0`00016000 ( 88.000 kb) 0.02% 0.00%
PAGE_READWRITE|PAGE_GUARD 4 0`00012000 ( 72.000 kb) 0.01% 0.00%
PAGE_EXECUTE 2 0`00003000 ( 12.000 kb) 0.00% 0.00%
--- Largest Region by Usage ----------- Base Address -------- Region Size ----------
Free 0`7fff0000 7ff5`7f7a0000 ( 127.959 Tb)
<unknown> 0`02912000 0`0ffee000 ( 255.930 Mb)
Image 7ffd`0ab5d000 0`010e4000 ( 16.891 Mb)
MappedFile 0`0102c000 0`01234000 ( 18.203 Mb)
Stack 0`1b350000 0`003f9000 ( 3.973 Mb)
Heap 0`022a8000 0`00101000 ( 1.004 Mb)
Other 0`00cd0000 0`00181000 ( 1.504 Mb)
TEB 7ff5`ff968000 0`00002000 ( 8.000 kb)
PEB 7ff5`ff967000 0`00001000 ( 4.000 kb)
这是它在！Dumpheap-stat输出中的外观
00007ffd0ad95740 4 2609 System.Byte[]
以下是！EEHeap-GC的输出
Number of GC Heaps: 1
generation 0 starts at 0x0000000002bd1030
generation 1 starts at 0x0000000002bd1018
generation 2 starts at 0x0000000002bd1000
ephemeral segment allocation context: none
segment begin allocated size
0000000002bd0000 0000000002bd1000 0000000002bd7fe8 0x6fe8(28648)
Large object heap starts at 0x0000000012bd1000
segment begin allocated size
0000000012bd0000 0000000012bd1000 0000000012bd9720 0x8720(34592)
Total Size: Size: 0xf708 (63240) bytes.
------------------------------
GC Heap Size: Size: 0xf708 (63240) bytes.
当我将数组大小更改为5000000时，这是我在！Dumpheap-Stat中看到的内容
00007ffd0ad95740 4 5000609 System.Byte[]
以下是！eeHeap-gc命令的输出
Number of GC Heaps: 1
generation 0 starts at 0x0000000002bd1030
generation 1 starts at 0x0000000002bd1018
generation 2 starts at 0x0000000002bd1000
ephemeral segment allocation context: none
segment begin allocated size
0000000002bd0000 0000000002bd1000 0000000002bd7fe8 0x6fe8(28648)
Large object heap starts at 0x0000000012bd1000
segment begin allocated size
0000000012bd0000 0000000012bd1000 000000001309e298 0x4cd298(5034648)
Total Size: Size: 0x4d4280 (5063296) bytes.
------------------------------
GC Heap Size: Size: 0x4d4280 (5063296) bytes.
和地址摘要如下
0:003> !address -summary
Mapping file section regions...
Mapping module regions...
Mapping PEB regions...
Mapping TEB and stack regions...
Mapping heap regions...
Mapping page heap regions...
Mapping other regions...
Mapping stack trace database regions...
Mapping activation context regions...
--- Usage Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal
Free 50 7fff`e153a000 ( 128.000 Tb) 100.00%
<unknown> 61 0`18a1d000 ( 394.113 Mb) 80.31% 0.00%
Image 163 0`031da000 ( 49.852 Mb) 10.16% 0.00%
MappedFile 12 0`019f8000 ( 25.969 Mb) 5.29% 0.00%
Stack 12 0`01000000 ( 16.000 Mb) 3.26% 0.00%
Heap 22 0`002ff000 ( 2.996 Mb) 0.61% 0.00%
Other 8 0`001bf000 ( 1.746 Mb) 0.36% 0.00%
TEB 4 0`00008000 ( 32.000 kb) 0.01% 0.00%
PEB 1 0`00001000 ( 4.000 kb) 0.00% 0.00%
--- Type Summary (for busy) ------ RgnCount ----------- Total Size -------- %ofBusy %ofTotal
MEM_PRIVATE 101 0`19d17000 ( 413.090 Mb) 84.18% 0.00%
MEM_IMAGE 163 0`031da000 ( 49.852 Mb) 10.16% 0.00%
MEM_MAPPED 19 0`01bc5000 ( 27.770 Mb) 5.66% 0.00%
--- State Summary ---------------- RgnCount ----------- Total Size -------- %ofBusy %ofTotal
MEM_FREE 50 7fff`e153a000 ( 128.000 Tb) 100.00%
MEM_RESERVE 51 0`1aa05000 ( 426.020 Mb) 86.82% 0.00%
MEM_COMMIT 232 0`040b1000 ( 64.691 Mb) 13.18% 0.00%
--- Protect Summary (for commit) - RgnCount ----------- Total Size -------- %ofBusy %ofTotal
PAGE_EXECUTE_READ 24 0`0262d000 ( 38.176 Mb) 7.78% 0.00%
PAGE_READONLY 71 0`00e1d000 ( 14.113 Mb) 2.88% 0.00%
PAGE_READWRITE 81 0`007df000 ( 7.871 Mb) 1.60% 0.00%
PAGE_WRITECOPY 31 0`00417000 ( 4.090 Mb) 0.83% 0.00%
PAGE_EXECUTE_WRITECOPY 3 0`00043000 ( 268.000 kb) 0.05% 0.00%
PAGE_EXECUTE_READWRITE 15 0`00016000 ( 88.000 kb) 0.02% 0.00%
PAGE_READWRITE|PAGE_GUARD 5 0`00015000 ( 84.000 kb) 0.02% 0.00%
PAGE_EXECUTE 2 0`00003000 ( 12.000 kb) 0.00% 0.00%
--- Largest Region by Usage ----------- Base Address -------- Region Size ----------
Free 0`7fff0000 7ff5`7f7d0000 ( 127.959 Tb)
<unknown> 0`02be2000 0`0ffee000 ( 255.930 Mb)
Image 7ffd`0ab5d000 0`010e4000 ( 16.891 Mb)
MappedFile 0`0134c000 0`01214000 ( 18.078 Mb)
Stack 0`1b760000 0`003f9000 ( 3.973 Mb)
Heap 0`0265d000 0`00101000 ( 1.004 Mb)
Other 0`00fd0000 0`00181000 ( 1.504 Mb)
TEB 7ff5`ff996000 0`00002000 ( 8.000 kb)
PEB 7ff5`ff99e000 0`00001000 ( 4.000 kb)
dupheap和eeheap的输出完全有意义。我不知道这些托管分配应该显示在哪里！地址-摘要
推荐答案
请尝试以下代码，分配20 MB：
static void Main(string[] args)
{
Console.WriteLine("Attach Windbg now");
Console.ReadLine();
int size = 20000000;
var something = new byte[size];
Console.WriteLine("Look again");
Console.ReadLine();
// not sure if its needed but have it so that this object is still referenced and optimizations don't remove it proactively
something[0] = 1;
}
开始时我的计算机显示
<unknown> 49 0`19502000 ( 405.008 Mb) 82.39% 0.00%
MEM_RESERVE 45 0`1b0d4000 ( 432.828 Mb) 88.05% 0.01%
MEM_COMMIT 240 0`03ac0000 ( 58.750 Mb) 11.95% 0.00%
在!address -summary的输出中。
现在执行
.loadby sos clr
bp kernel32!VirtualAlloc
g
并在控制台应用程序中按Enter键。它将命中断点，您将看到
0:000> k
Child-SP RetAddr Call Site
00000000`001ce2b8 000007fe`f77c265a KERNEL32!VirtualAlloc
...
00000000`001ce5f0 000007fe`f77c7ece clr!WKS::GCHeap::Alloc+0x348
00000000`001ce640 000007fe`981600f7 clr!JIT_NewArr1+0x49e
...
0:000> !clrstack
OS Thread Id: 0x5c4 (0)
Child SP IP Call Site
00000000001ce778 0000000076cb5c68 [HelperMethodFrame: 00000000001ce778]
00000000001ce8f0 000007fe981600f7 ManagedVirtualAlloc.Program.Main(System.String[])
00000000001cec30 000007fef7829e03 [GCFrame: 00000000001cec30]
因此您可以看到，从main方法中，.NET运行时尝试分配虚拟内存以适应新的字节数组(如JIT_NewArr1所示)。
然而，查看传递给VirtualAlloc()的参数(请注意，kb对于64位是误导的)，我们可以看到
0:000> r
...
rcx=0000000012392000 // address of an already reserved memory region
rdx=000000000130b000 // size: 19968000
r8=0000000000001000 // MEM_COMMIT
r9=0000000000000004 // PAGE_READWRITE
...
0:000> kb; *** Warning: misleading arguments for 64 bit!
RetAddr : Args to Child : Call Site
000007fe`f77c265a : 00000000`00000000 00000000`00000000 00000000`001ce369 000007fe`00000000 : KERNEL32!VirtualAlloc
我们看到它指定了以前保留的地址，现在应该提交。调用(Enterg)后，我们看到一些(~20MB)保留内存已被转换为已提交内存，而<unknown>数量仍然相同。
<unknown> 49 0`19502000 ( 405.008 Mb) 82.39% 0.00%
MEM_RESERVE 45 0`19dc1000 ( 413.754 Mb) 84.17% 0.00%
MEM_COMMIT 238 0`04dd3000 ( 77.824 Mb) 15.83% 0.00%
结论：
.NET提前保留了大量内存。该内存将在启动应用程序后立即显示为<unused>。然后，如果可能，它将使用保留和提交内存，因此并不是每一次分配都会导致新的VirtualAlloc()调用。
更多内部组件：
我们还看到.NET框架非常聪明：它只分配了19968000字节，而不是20000000字节，因为它能够重用已经处于提交状态的内存块的一些字节。查看指针：
VirtualAlloc pointer: 0x0000000012392000
"something" variable: 0x0000000012389710
Something变量指向由VirtualAlloc()调用返回的内存块前面的内存区域。