Messages in this thread | | | Subject | Re: [RFC PATCH v3 12/24] x86/mm: Modify ptep_set_wrprotect and pmdp_set_wrprotect for _PAGE_DIRTY_SW | From | Dave Hansen <> | Date | Fri, 14 Sep 2018 13:46:16 -0700 |
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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.
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