mirror of https://gitee.com/openkylin/linux.git
85 lines
1.8 KiB
C
85 lines
1.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Example of using hugepage memory in a user application using the mmap
|
|
* system call with MAP_HUGETLB flag. Before running this program make
|
|
* sure the administrator has allocated enough default sized huge pages
|
|
* to cover the 256 MB allocation.
|
|
*
|
|
* For ia64 architecture, Linux kernel reserves Region number 4 for hugepages.
|
|
* That means the addresses starting with 0x800000... will need to be
|
|
* specified. Specifying a fixed address is not required on ppc64, i386
|
|
* or x86_64.
|
|
*/
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include <unistd.h>
|
|
#include <sys/mman.h>
|
|
#include <fcntl.h>
|
|
|
|
#define LENGTH (256UL*1024*1024)
|
|
#define PROTECTION (PROT_READ | PROT_WRITE)
|
|
|
|
#ifndef MAP_HUGETLB
|
|
#define MAP_HUGETLB 0x40000 /* arch specific */
|
|
#endif
|
|
|
|
/* Only ia64 requires this */
|
|
#ifdef __ia64__
|
|
#define ADDR (void *)(0x8000000000000000UL)
|
|
#define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB | MAP_FIXED)
|
|
#else
|
|
#define ADDR (void *)(0x0UL)
|
|
#define FLAGS (MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB)
|
|
#endif
|
|
|
|
static void check_bytes(char *addr)
|
|
{
|
|
printf("First hex is %x\n", *((unsigned int *)addr));
|
|
}
|
|
|
|
static void write_bytes(char *addr)
|
|
{
|
|
unsigned long i;
|
|
|
|
for (i = 0; i < LENGTH; i++)
|
|
*(addr + i) = (char)i;
|
|
}
|
|
|
|
static int read_bytes(char *addr)
|
|
{
|
|
unsigned long i;
|
|
|
|
check_bytes(addr);
|
|
for (i = 0; i < LENGTH; i++)
|
|
if (*(addr + i) != (char)i) {
|
|
printf("Mismatch at %lu\n", i);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int main(void)
|
|
{
|
|
void *addr;
|
|
int ret;
|
|
|
|
addr = mmap(ADDR, LENGTH, PROTECTION, FLAGS, -1, 0);
|
|
if (addr == MAP_FAILED) {
|
|
perror("mmap");
|
|
exit(1);
|
|
}
|
|
|
|
printf("Returned address is %p\n", addr);
|
|
check_bytes(addr);
|
|
write_bytes(addr);
|
|
ret = read_bytes(addr);
|
|
|
|
/* munmap() length of MAP_HUGETLB memory must be hugepage aligned */
|
|
if (munmap(addr, LENGTH)) {
|
|
perror("munmap");
|
|
exit(1);
|
|
}
|
|
|
|
return ret;
|
|
}
|