????

1
?????(1)
2
?????????

• ????????????,???????????????????????????????
• ???????,??
• ??????(????)
• ???????????(malloc, new)
• ?????????

3
??????????

• ????,???????????,???,?????????????,
• ?????????????????????????????

?? ??????? ???? ???
???,??,12300????17300?????????????????
5000????????
4
???????????????

• ????(allocation)???(deallocation)

1000????????
30000??????
????
30000??????
????
??
500????????
??30000??????
????
5
OS??????API

• Unix brk, sbrk, mmap, etc.
• Win32 VirtualAlloc, VirtualFree, MapViewOfFile,
  etc.
• ????????

6
??????????????????????API???

• C
• ???????, ????, malloc/free, strdup, etc.
• C
• ???????, ????, new/delete, STL????,
• Java, C
• new, String?????????
• Garbage Collection
• Python
• ???, ??, ????????, ???????????
• Garbage collection
• Perl, ????????,Visual Basic,

7
? OS?API???????????API???

• malloc/free???OS??????????????????(??????)

OS?API (sbrk, brk, etc.)
malloc/ free
OS
????? ????? (malloc/free??)
????????
8
???????????????

• ????????????????,???????????????????

512M (??????)
????
0
gcc
enshu.exe
enshu.exe
emacs
IE
?????
9
OS???????????????????

• ???????
• ?????????????????,?????????????????
• ?????????????????????????
• ???????
• ?????????????????????
• ?????????
• ????????????????????,???????????????

10
OS???????????????
????????????????
???
????
L
0
????A??????
??????
OS
L
0
????B??????
L
0
????C??????
11
????(Virtual Memory)

• ???OS???????????
• ????
• ????????
• ??????????????
• ???????????????(?????)?
• ????????????????????

12
????

• ???????
• ??????????????????
• ??????????????????????
• ???????
• ????????????????????????(???????????)
• ?????????
• ??????????????????????????

13
????

• ????????????????????????????
• ??????(CPU)?OS??????
• ??????
• CPU???
• OS??????????API (??)

14
??????????

• ??????
• ?????????????(??????)?,?????????????????(??????)??
  ?????
• ?????
• ???????????????,???????????????????????????
• ???????????????????????????????????

15
??????????????????

• ??????
• ????????(???????????)??????
• ??????
• ??????????????????

16
??????

• ??????????????????????????
• main() p 10000 printf(d\n, p)
• ????????????????
• ?????????????

??????10000 ?????
17
????????

• ??????????????????
• ????A?10000???????B?10000?????????
• ??????????????,???????????(?????bit??OS???????)

0
232 1
???????? A
???????? B
???????? C
18
??????

• ?????????????????????????
• ??????????0 ?????? 1
• (??)???????????????????

19
?????????(1)

• ???????, ??????????,????????????????????(??????
  Address Translation)???

???????ID, ???????
?????
?Paddr?
?ASID, Laddr?
????????
CPU
20
?????????(2)

• ???????????????????????????????
• ????????????????????(????? paging)???????

21

• ?????????CPU??????

22
?????????(Memory Management Unit MMU)

• ?? ????????????????????,?????
• ????????
• ????????????????????
• ??????
• ???

MMU
23
???????????CPU???(??)

• ??????? ?????? ????
• ? load r1, r2 (store?????)
• ????r1????????a??????

a??????? ????p????
??????
??(????)?? page fault
NO
a?read??
???????
??(????)?? protection fault
NO
YES
??????p???
24
???

• CPU (MMU)???????????
• ????(read/write? etc.)
• ??????
• ????????????
• ????,????????????????????????????
• ??????(???????)???

25
???

• ???????,????,??????,?????????
• ?????4096???,8192?????????????????

0x1000
?ASID, ??????? ? ????????? ?ASID, ???????? ?
??????????
0x2000
0x3000
0x4000
26
????????

• ? 32 bit??????.4096??????
• ???????ID, ???????????????????????

20 bit
12 bit
?????????
???????
???????
????
??????
0
Mapping?? (???????????)
1
27
?????

• ????
• ?????(readable)
• ?????(writable)
• ????????????
• ??????
• ??(reference) bit (read??set)
• ??(dirty) bit (write??set)

28
Mapping??

• ????????????, ??????????
• ????????
• ??????????????
• ?????????????, ??
• ??????????.??,
• OS??????????????????????
• CPU?????????(OS?????)

29
???????

• ???????
• ??????????
• ?????????, ??????????????????????,?????????
• TLB (Translation Lookaside Buffer)
• CPU????, ??100???????????(??fully associative)
• ?? ?????????????

30
????????????????????????

• ??
• 32 bit??????. 20 bit?????
• 1????32 bit (?????????)
• 220 4 n 4n MB
• n ?????????? ? ????????????
• ???????(?????)

31
??????????

• ????????????????????????
• ??????????

32
??????????
10 bit
10 bit
12 bit
a1
a2
o
a1
a2
33
64bit?????

• Madhusudhan Tallurl, Mark D. Hill, Yousef A.
  Khalidi. A New Page Table for 64-bit Address
  Spaces. SOSP 1995

34
?????????CPU??? ??? (read)

• read(a) p,attr lookup_TLB(a) if (!found)
  p,attr lookup_page_table(a) if (!found)
  raise page fault if (!attr.readable) raise
  protection fault if (!attr.user CPU_mode
  user) raise protection fault read p /
  in cache or memory / set reference bit for a

35
Write???

• write(a, v) p,attr lookup_TLB(a) if
  (!found) p,attr lookup_page_table(a) if
  (!found) raise page fault if (!attr.writable)
  raise protection fault if (!attr.user
  CPU_mode user) raise protection fault
  write v to p / in cache or memory / set
  reference/dirty bit for a

36
???????????????????????

• ?????
• (?????????)???????????
• ??????????
• ????????????????????,??(??)?????????
• ?????????????????,???????

???? ?????
??? ?????
???? ?????
37
????????????????????????

• ?????????????
• ?????,protection fault, access violation