Do you understand virtual memory versus physical memory? When a process asks for memory, especially huge chunks of it, one common strategy is to allocate a small part of it and then mark virtual memory (which is on disk usually) as allocated for the rest of the request.
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Thanks for replying.
I have learned about different mapping methods of virtual memory to physical memory.
But whole physical memory is divided into two parts: one for Kernel, the other for User and usually 1:3.
For user part, user threads or processes share the physical memory by virtual memory mapping, so it means that each thread gets it memory without contention in the allocation even though they actually share the same physical memory? (I know the conflict can happen when they load their virtual memory segment to the physical memory area)
For kernel part, there is part of memory(For 4GB memory, it's 896MB) that can be used directly without mapping from virtual memory to physical memory. If parallel allocation happens in this area(such as parallel system call), will contention exist? If yes, how does it solve the performance problem?
Thanks
Hello!
First of all, forgive me for bad English.
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Hi all,
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Hi,
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#include <stdio.h>
#include <stdlib.h>
#include<string.h>
#define... (1 Reply)
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Hi Experts
I need some help in static memory allocation in C. I have a program in which I declared 2 variables, one char array and one integer. I was little surprised to see the addresses of the variables.
First:
int x;
char a;
printf("%u %u\n', &x, a);
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Hello Guys
I have a small confusion in the dynamic memory allocation concept.
If we declare a pointer say a char pointer, we need to allocate adequate memory space.
char* str = (char*)malloc(20*sizeof(char));
str = "This is a string";
But this will also work.
char* str = "This... (2 Replies)
hi
in the following code, how the memory is allocated for a1 which holds the values of a2 after cpy function call.
#include <stdio.h>
#include <string.h>
void cpy(char* d, const char* s){
while(*d++=*s++);
}
main(){
char* a1;
char* a2="done";
cpy(a1,a2);
... (3 Replies)
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