Hi Helge, > I tried your patch on top of a 2.6.33.2 kernel (SMP, 32bit, PA8500 (PCX-W) CPU). > I still do see all the page faults as before. They even seem to trigger > faster than with a few of Dave's patches. > > I usually run this command > i=0; while true; do i=$(($i+1)); echo Run $i; ./minifail_dave; done; > in a few screen sessions in parallel. The reason running multiple screens in parallel exposes further problems is the implementation of ptep_set_wrprotect is broken. It simply sets the write protect bit in the pte and doesn't purge the existing translation. So, the parent continues to merrily write to the write protected page until the TLB entry is purged and reloaded. More processes make it more likely the entry will be replaced and trigger a COW break. This is why my versions of the minifail test which monitor the stack region used by the thread don't cause a COW break immediately after the fork. When compiled at -O0, the loop index is constantly being stored to the stack. Dave -- J. David Anglin dave.anglin@xxxxxxxxxxxxxx National Research Council of Canada (613) 990-0752 (FAX: 952-6602) -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
