-#ifndef MADV_REMOVE
-#define MADV_REMOVE KERNEL_MADV_REMOVE
-#endif
-
-int os_drop_memory(void *addr, int length)
-{
- int err;
-
- err = madvise(addr, length, MADV_REMOVE);
- if(err < 0)
- err = -errno;
- return err;
-}
-
-int can_drop_memory(void)
-{
- void *addr;
- int fd, ok = 0;
-
- printk("Checking host MADV_REMOVE support...");
- fd = create_mem_file(UM_KERN_PAGE_SIZE);
- if(fd < 0){
- printk("Creating test memory file failed, err = %d\n", -fd);
- goto out;
- }
-
- addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
- MAP_SHARED, fd, 0);
- if(addr == MAP_FAILED){
- printk("Mapping test memory file failed, err = %d\n", -errno);
- goto out_close;
- }
-
- if(madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0){
- printk("MADV_REMOVE failed, err = %d\n", -errno);
- goto out_unmap;
- }
-
- printk("OK\n");
- ok = 1;
-
-out_unmap:
- munmap(addr, UM_KERN_PAGE_SIZE);
-out_close:
- close(fd);
-out:
- return ok;
-}
-