On Sun, 2015-03-15 at 16:26 +0100, Oleg Nesterov wrote: > On 03/15, Davidlohr Bueso wrote: > > > > On Sun, 2015-03-15 at 15:21 +0100, Oleg Nesterov wrote: > > > I didn't even read this version, but honestly I don't like it anyway. > > > > > > I leave the review to Cyrill and Konstantin though, If they like these > > > changes I won't argue. > > > > > > But I simply can't understand why are you doing this. > > > > > > > > > > > > Yes, this code needs cleanups, I agree. Does this series makes it better? > > > To me it doesn't, and the diffstat below shows that it blows the code. > > > > Looking at some of the caller paths now, I have to disagree. > > And I believe you are wrong. But let me repeat, I leave this to Cyrill > and Konstantin. Cleanups are always subjective. > > > > In fact, to me it complicates this code. For example. Personally I think > > > that MMF_EXE_FILE_CHANGED should die. And currently we can just remove it. > > > > How could you remove this? > > Just remove this flag and the test_and_set_bit(MMF_EXE_FILE_CHANGED) check. > Again, this is subjective, but to me it looks ugly. Why do we allow to > change ->exe_file but only once? Ok I think I am finally seeing where you are going. And I like it *a lot* because it allows us to basically replace mmap_sem with rcu (MMF_EXE_FILE_CHANGED being the only user that requires a lock!!), but am afraid it might not be possible. I mean currently we have no rule wrt to users that don't deal with prctl. Forbidding multiple exe_file changes to be generic would certainly change address space semantics, probably for the better (tighter around security), but changed nonetheless so users would have a right to complain, no? So if we can get away with removing MMF_EXE_FILE_CHANGED I'm all for it. Andrew? Thanks, Davidlohr -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>