> can get at most 2GB. Newer glibc's allow you to tune the definition
> of "small" via an environment variable.
eventually, perhaps libc will be smart enough to create
more arenas in mmaped space once sbrk fails. note, though,
that you *CAN* actually malloc a lot more than 1G: you just
have to avoid causing mmaps that chop your VM at TASK_UNMAPPED_BASE:
#include <unistd.h>
#include <stdlib.h>
#include <fcntl.h>
void printnumber(unsigned n) {
char number[20];
int i;
for (i=sizeof(number)-1; i>=0 && n; i--) {
number[i] = '0' + (n % 10);
n /= 10;
}
i++;
write(1,number+i, sizeof(number)-i);
}
int main() {
unsigned total = 0;
const unsigned size = 32*1024;
while (malloc(size)) {
total += size;
printnumber(total>>20);
write(1,"\n",1);
}
return 0;
}
compile -static, of course; printnumber is to avoid stdio, which seems
to use mmap for a small scratch buffer. I allocated 2942 MB on my 128M
machine(had to add a swapfile temporarily, since so many tiny mallocs
do touch nontrivial numbers of pages for arena bookkeeping.)
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This archive was generated by hypermail 2b29 : Sat Apr 07 2001 - 21:00:18 EST