On 09/05/2017 08:12 PM, Rob Landley wrote: > On 09/05/2017 08:24 AM, Alan Cox wrote: >>>> honoring the suid bit if people feel that way. I just wanna unblock >>>> vfork() while still running this code. >> >> Would it make more sense to have a way to promote your vfork into a >> fork when you hit these cases (I appreciate that fork on NOMMU has a much >> higher performance cost as you start having to softmmu copy or swap >> pages). > > It's not the performance cost, it's rewriting all the pointers. > > Without address translation, copying the existing mappings to a new > range requires finding and adjusting every pointer to the old data, > which you can do for the executable mappings in PIE* binaries, but > tracking down all the pointers on the stack, heap, and in your global > variables? Flaming pain. > > Making fork() work on nommu is basically the same problem as making > garbage collection work in C on mmu. Thus those of us who defend vfork() > from the people who don't understand why it exists periodically > suggesting we remove it. So is exec(NULL, argv, envp) a reasonable thing to want? Rob -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
