[lkml]   [2018]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC PATCH v3 12/24] x86/mm: Modify ptep_set_wrprotect and pmdp_set_wrprotect for _PAGE_DIRTY_SW
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.

 \ /
  Last update: 2018-09-14 22:47    [W:0.081 / U:15.404 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site