On Fri, Nov 27, 2009 at 10:30 AM, Paul Mackerras <pau...@samba.org> wrote: > Li Yang writes: > >> That's my concern too. But after all mmap without O_SYNC on I/O >> devices should be deprecated. > > It should? Why? > > Shouldn't the onus rather be on those proposing an incompatible change > to the kernel ABI, such as this is, to show why the change is > absolutely essential?
In addition to the performance issue I stated earlier in this thread. There was also cache paradoxes problem too. If a memory region is shared between two cores/OS'es and Linux can't map the region with the same cacheable property as the other OS had mapped, there will be a problem. The best solution for this problem is to make the cacheablity controllable. And it seems to be generic issue which does not only exist on powerpc platforms. So it might be better dealt with the already existed O_SYNC flag which was meant to deal with this kind of thing. I agree with your comment in another email that device tree could be used, but that solution is not generic enough though. - Leo _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev