On Wed, 31 Aug 2005, Martin J. Bligh wrote: > --Hugh Dickins <[EMAIL PROTECTED]> wrote (on Wednesday, August 31, 2005 > 14:42:38 +0100): > > > > Which is indeed a further disincentive against shared page tables. > > Or shared pagetables a disincentive to randomizing the mmap space ;-)
Fair point! > They're incompatible, but you could be left to choose one or the other > via config option. Wouldn't need config option: there's /proc/sys/kernel/randomize_va_space for the whole running system, compatibility check on the ELFs run, and the infinite stack rlimit: enough ways to suppress randomization if it doesn't suit you. > 3% on "a certain industry-standard database benchmark" (cough) is huge, > and we expect the benefit for PPC64 will be larger as we can share the > underlying hardware PTEs without TLB flushing as well. Okay - and you're implying that 3% comes from _using_ the shared page tables, rather than from avoiding the fork/exit overhead of setting them up and tearing them down. And it can't use huge TLB pages because... fragmentation? Hugh - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
