目录

函数声明

函数原型与使用

函数声明

void *malloc_huge_pages(size_t size);
void free_huge_pages(void *ptr);

函数原型与使用

#include <stdio.h>
#include <assert.h> 
#include <stdlib.h> 
#include <string.h>
#include <sys/mman.h> 
 
#define HUGE_PAGE_SIZE (2 * 1024 * 1024) 
 
#define ALIGN_TO_PAGE_SIZE(x) \
    (((x) + HUGE_PAGE_SIZE - 1) / HUGE_PAGE_SIZE * HUGE_PAGE_SIZE) 
 
void *malloc_huge_pages(size_t size) 
{ 
    // Use 1 extra page to store allocation metadata 
    // (libhugetlbfs is more efficient in this regard) 
    size_t real_size = ALIGN_TO_PAGE_SIZE(size + HUGE_PAGE_SIZE); 
    char *ptr = (char *)mmap(NULL, real_size, 
                            PROT_READ | PROT_WRITE, 
                            MAP_PRIVATE | MAP_ANONYMOUS | 
                            MAP_POPULATE | MAP_HUGETLB, -1, 0); 
    if (ptr == MAP_FAILED) { 
        // The mmap() call failed. Try to malloc instead 
        ptr = (char *)malloc(real_size); 
        if (ptr == NULL) 
            return NULL; 
        real_size = 0; 
    } // Save real_size since mmunmap() requires a size parameter 
    *((size_t *)ptr) = real_size; 
 
    // Skip the page with metadata 
    return ptr + HUGE_PAGE_SIZE; 
}
 
void free_huge_pages(void *ptr) 
{ 
    if (ptr == NULL) 
        return; 
    
    // Jump back to the page with metadata 
    void *real_ptr = (char *)ptr - HUGE_PAGE_SIZE; 
 
    // Read the original allocation size 
    size_t real_size = *((size_t *)real_ptr); 
    assert(real_size % HUGE_PAGE_SIZE == 0); 
    
    if (real_size != 0) 
        // The memory was allocated via mmap() 
        // and must be deallocated via munmap() 
        munmap(real_ptr, real_size); 
    else 
        // The memory was allocated via malloc() 
        // and must be deallocated via free() 
        free(real_ptr); 
}
 
int main()
{
	char *string = malloc_huge_pages(1024);	
	if(string == NULL) {
		printf("error: malloc_huge_pages error.\n");
	}
 
	strcpy(string, "Hello World!");
	printf("string: %s\n", string);
 
	free_huge_pages(string);
 
	return 0;
}