On Fri, Sep 30, 2011, Vadim Zhukov wrote: > Hello all. > > After some talks on opennet.ru I dived into the sys/uvm/ and other > places, having a few more or less tech-nical questions raised now. Can > anybody answer them?
Very nice. > 1. amap_share_protect() in sys/uvm/uvm_amap.c is totally unused, is there > any point for keeping it around? No, there's probably more than a few functions no longer used. It's hard to know when you delete the last call to a function. Diffs welcome. > 2. Am I right that W^X techniques like segment splitting on i386 are not > used in kernel? Not presently. > 2a. If yes, what's the main stopper here? A diff. > 3. What's the point in keeping sys/arch/i386/i386/pmapae.c? Are there any > plans for re-enabling PAE support? Someday, if somebody gets it to work, it'd be nice to have. Some people may want to keep running i386, but most new CPUs let you use the NX bit with PAE, so it's helpful even with small amounts of memory. > 4. Stack gap limit (STACKGAP_RANDOM) on almost all archs is 256*1024 > (some use less). Are there any pitfalls in growing it on (64-bit) archs > like amd64, changing random bit count from 15 to something more > effective? I can't think of any reason why 1GB or even more wouldn't work on amd64. You can try it and see.
