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Subjectabout /proc/meminfo and mmap
Hi, all:

My PC have 128M RAM, but in /proc/meminfo, it display 122424K, not
128*1024K = 131072K, what does this mean?

My program need to a 32M buffer, so I add "append="mem=96M"" to lilo.conf,
then the PC only know 96M mem, I can use the rest 32M. Following is a
simple example:

int fd = open("/dev/mem", O_RDWR);
if (fd < 0) {
printf("failed to open /dev/mem\n");
return -1;
start = (DATA *) mmap(0, length*sizeof(DATA),PROT_READ|PROT_WRITE,
if (start == (DATA *) (-1) ) {
printf("failed to map /dev/mem\n");
return -1;

// do ...

munmap(start, length);


Is there some problem? Or does the DATA are all in real RAM? Any
suggestions are welcome.

Thanks a lot.



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