리눅스커널-06

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1 C h a p t e r 06

2 CPU CPU CPU 1MB 600KB 500KB 4GB 512MB 1GB 230

3 231

4 Virtual Memory Physical Memory Virtual address Physical address 0 CPU 4GB 3GB 1GB 61 init proc1maps cat 0x xC x GB paging 232

5 CPU CPU MMUMemory Management Unit MMU 233

$taskstruct struct mmstruct mm mmstruct includelinuxschedh struct mm_struct { struct vm_area_struct * mmap; rb_root_t mm_rb; struct vm_area_struct * mmap_cache; pgd_t * pgd; atomic_t mm_users;$

6 taskstruct struct mmstruct mm mmstruct includelinuxschedh struct mm_struct { struct vm_area_struct * mmap; rb_root_t mm_rb; struct vm_area_struct * mmap_cache; pgd_t * pgd; atomic_t mm_users; atomic_t mm_count; int map_count; struct rw_semaphore mmap_sem; spinlock_t page_table_lock; struct list_head mmlist; unsigned long start_code, end_code, start_data, end_data; unsigned long start_brk, brk, start_stack; unsigned long arg_start, arg_end, env_start, env_end; unsigned long rss, total_vm, locked_vm; unsigned long def_flags; unsigned long cpu_vm_mask; unsigned long swap_address; unsigned dumpable:1; mm_context_t context; }; 234

7 struct vmareastruct mmap vmareastruct vmareastruct mmap 61 vmareastruct vmareastruct includelinuxmmh struct vm_area_struct { struct mm_struct * vm_mm; unsigned long vm_start; unsigned long vm_end; struct vm_area_struct *vm_next; unsigned long vm_flags;... }; vmmm mmstruct vmstart vmend 61 vmflags vmnext vmnext NULL pgdt pgd pgd startcodeendcode 235

8 startdataenddata BSSBlock Started by Symbol startbrkbrk heap malloc free brk startstack envstartenvendargstartargend 3GB envstart envend argstart argend main env argv argend main sysshmget

9 63 237

10 01 #include<stdio.h> 02 #include<malloc.h> 03 #include<unistd.h> 04 #include<linux/unistd.h> 05 #include<errno.h> 06 #define NR_getvminfo int vbss; 08 int vdata=1; struct vminfo { 11 unsigned long startcode; 12 unsigned long endcode; 13 unsigned long startdata; 14 unsigned long enddata; 15 unsigned long startbrk; 16 unsigned long brk; 17 unsigned long startstack; 18 }; _syscall2(int, getvminfo, int, pid, struct vminfo*, vm) 238

11 21 22 int main() 23 { int i, pid, vstack=2; 26 struct vminfo vm; pid = getpid(); 29 i = getvminfo(pid, &vm); printf("processs memory information\n"); 32 printf("location of main Function in Code Segment: %p(%lx~%lx)\n",main, vm.startcode, vm.endcode); 33 printf("=============================================\n"); 34 printf("location of Initialied Data in Data Area: %p(%lx~%lx)\n",&vdata, vm.startdata, vm.enddata); 35 printf("=============================================\n"); 36 printf("location of uninitialized Data in BSS Area: %p(%lx~%lx)\n",&vbss, vm.enddata, vm.startbrk); 37 printf("=============================================\n"); 38 printf("stack Location:%p(%lx~)\n",&vstack, vm.startstack); 39 printf("=============================================\n"); sbrk(3); 42 char*b = sbrk(0); 43 i = getvminfo(pid, &vm); 44 printf("heap Location:%p(%lx~%lx)\n",b, vm.startbrk, vm.brk); 45 printf("=============================================\n"); 46 return 0; 47 } 239

12 01 #include <linux/kernel.h> 02 #include <linux/module.h> 03 #include <sys/syscall.h> 04 #include <asm/uaccess.h> 05 #include <linux/mm.h> #define NR_getvminfo asmlinkage int (*saved_entry)(void); 10 extern void *sys_call_table[]; struct vminfo { 13 unsigned long startcode; 14 unsigned long endcode; 15 unsigned long startdata; 16 unsigned long enddata; 17 unsigned long startbrk; 18 unsigned long brk; 19 unsigned long startstack; }; asmlinkage int sys_getvminfo(int pid, struct vminfo *uvm) 24 { struct vminfo vm; 27 struct task_struct *t; 240

13 28 struct mm_struct *mm; t = find_task_by_pid(pid); 31 mm = t->active_mm; vm.startcode = mm->start_code; 34 vm.endcode = mm->end_code; 35 vm.startdata = mm->start_data; 36 vm.enddata = mm->end_data; 37 vm.startbrk = mm->start_brk; 38 vm.brk = mm->brk; 39 vm.endenv = mm->env_end; 40 vm.startstack = mm->start_stack; copy_to_user(uvm, &vm, sizeof(struct vminfo)); 43 return 0; 44 } int module_start() 47 { saved_entry = sys_call_table[ NR_getvminfo]; 50 sys_call_table[ NR_getvminfo] = sys_getvminfo; 51 return 0; 52 } void module_end(void) 55 { 56 sys_call_table[ NR_getvminfo] = saved_entry; 57 } module_init(module_start); 60 module_exit(module_end); MODULE_LICENSE("GPL"); 241

14 TARGET = getvminfo INCLUDE = -isystem /usr/src/linux /include CFLAGS = -O2 -D KERNEL -DMODULE $(INCLUDE) //CFLAGS = -O2 $(INCLUDE) CC = gcc ${TARGET}.o: ${TARGET}.c clean: rm -rf ${TARGET}.o #gcc -o app_getvminfo app_getvminfo.c #insmod getvminfo.o #./app_getvminfo 242

15 243

16 4GB 4KB 8KB 512MB 512MB4KB 4GB 4KB n n n 244

17 64Task itask j page table 3 245

18 65 64 Task i 023 PFNPage Frame Number PPresent i1 CPU 32bit 20bit 12bit 246

19 65 0x100 0x x K0x1000 0x11004KB 0x100 0x1001 0x bit 1 P 0 page fault Demand Paging 4GB 4KB byte 4MB 1M 4M

20 CPU MMU 2 x86 CPU protected mode 16bit 16bit 20bit 1MB real mode bit 16bit 16MB selector 24bit base address descriptor table bit 64KB bit 4GB 8086 CPU i MMU 248

21 1 i MMU linear address 16bit 32bit 68 TITable Indicator RPLRequested Privilege Level 3 249

22 64bit 32bit 20bit 4GB GDTGlobal Descriptor Table LDTLocal Descriptor Table GDT GDTR LDT LDTR 2bit DPLDescriptor Privilege Level CPU CPLCurrent Privilege Level RPL CPL DPL CPL 32bit 3 10bit 10bit 12bit

23 69 CR3 10bit 03FF bit 4byte 4KB bit 4KB

24 4KB 12bit 69 12bit KB 4GB MMU TLBTranslation Lookaside Buffer TLB TLB TLB bit 0x bit bit bit CR3 CR364KB 64K 10bit K 10bit 10bit 0 0 4K 12bit 252

25 253

26 3 i386 Alpha CPU 64bit bit 32bit i

27 i pgdtpmdtptet pgdoffset pmdoffset pteoffset CR3 pgdoffset pmdoffset pteoffset pgdoffsetmmaddress pmdoffsetdiraddress pteoffsetdiraddress pgdnonepgdpmdnonepmdptenonex

28 pgdpresentpgdpmdpresentpmdptepresentpte Present 1 pgdclearpgdpmdclearpmdpteclearpte pgdpagepgd pmdpagepmd ptepagex page 256

29 01 asmlinkage int sys_getmeminfo(int pid) 02 { 03 struct task_struct *t; 04 struct mm_struct *mm; 05 struct vm_area_struct *mmap; 06 struct file *file; char *filename; 09 char *buf; t = find_task_by_pid(pid); 12 mm = t->active_mm; 13 mmap = mm->mmap; 14 buf = (char*)kmalloc( 512, GFP_KERNEL); while(mmap) { 17 printk("%08lx - %08lx", mmap->vm_start, mmap->vm_end ); 18 file = mmap->vm_file; 19 if(file){ 20 filename = d_path(file->f_dentry, file->f_vfsmnt, buf, 512); 21 printk("%s \n", filename ); 22 } 23 else{ 24 printk("\n"); 25 } 26 mmap = mmap->vm_next; 27 } 28 return 0; 29 } 257

30 01 /* app_displaymeminfo.c */ #define NR_getmeminfo _syscall1(int, getmeminfo, int, pid) int main(int argc, int *argv[]) 07 { 08 int i, pid; pid = atoi(argv[1]); 11 i = getmeminfo(pid); 12 } TARGET = getmeminfo INCLUDE = -isystem /usr/src/linux /include CFLAGS = -O2 -D KERNEL -DMODULE $(INCLUDE) //CFLAGS = -O2 $(INCLUDE) CC = gcc ${TARGET}.o: ${TARGET}.c 258

31 clean: rm -rf ${TARGET}.o #gcc -o app_displaymeminfo app_displaymeminfo.c #insmod getmeminfo.o #./app_displaymeminfo 259

32 613 cat procslabinfo gfpmask allocpagesgfpmaskorder 2 order page 260

33 allocpagegfpmask allocpages order 0 getfreepagesgfpmaskorder 2 order getfreepagegfpmask getzeroedpagegfpmask 0 getdmapagesgfpmaskorder DMA getfreepages gfpmask GFPDMA kmallocsizeflags size vmallocsize size freepagespageorder 2 order freepagesaddrorder 2 order freepagepage freepageaddr kfreeobjp kmalloc vfreeaddr vmalloc 261

34 FIFOOPTOptimal Page replacementlru Least Recently UsedLFULeast Frequently UsedMFUMost Frequently Used FIFO OPT LFU MFU LRU LRU LRU LRU LRU LRU LRU LRU Approximation Page Replacement Accessed Dirty 262

35 614 kswapd kswapd 615 kswapdinit kswapdcansleep kswapdbalance 263

36 kswapdbalance kswapdbalancepgdat trytofreepageszone shrinkcaches LRU activelist inactivelist swapouttrytofreepageszone 616 trytoswap out swapout mmstruct swapoutvma swapoutpgd swapoutpmd trytoswapout 264

Microsoft PowerPoint - LN_7_Linux_MM.ppt [호환 모드]

Microsoft PowerPoint - LN_7_Linux_MM.ppt [호환 모드] 프로젝트 1 Memory Management 단국대학교컴퓨터학과 29 백승재 ibanez1383@dankook.ac.kr k k http://embedded.dankook.ac.kr/~ibanez1383 강의목표 리눅스의물리메모리관리기법이해 할당 / 해제기법 리눅스의가상메모리관리기법이해 할당 / 해제기법 리눅스의물리메모리와가상메모리연결 / 혹은변환기법이해 가상메모리개념