On 09/14/2018 01:39 PM, Yu-cheng Yu wrote:
> With the updated ptep_set_wrprotect() below, I did MADV_WILLNEED to a shadow
> stack of 8 MB, then 10,000 fork()'s, but could not prove it is more or less
> efficient than the other. So can we say this is probably fine in terms of
> efficiency?
Well, the first fork() will do all the hard work. I don't think
subsequent fork()s will be affected.
Did you do something to ensure this code was being run?
I would guess that a loop like this:
for (i = 0; i < 10000; i++) {
mprotect(addr, len, PROT_READ);
mprotect(addr, len, PROT_READ|PROT_WRITE);
}
might show it better.
