Hi! to begin my quest in kernel hacking, i decided it would be wise to first read some of the existing source, to get a feel for how things operate (famous last words :^). the oom_kill.c in kernel/ is nice to read, as are some others. however, sched.c doesn't seem so nice =) in many of the functions, there are goto's with no apparent reason, especially in schedule() itself (look at move_rr_last/back and in_interrupt). is there a reason for this? i have yet to look at the gcc -save-temps output to see if its some kind of optimization or some form of code obscurity. I would imagine gcc would replace a goto with a jmp (on x86 at least) in almost all cases, unless its smarter than that. some parts are clearly a loop of some sort, but others, as mentioned above, exist with only one calling goto present, and their return is either a return from schedule() or a goto back to right after the goto. would replacing some of the goto insanity with plain linear code improve performance any (negligible most likly, but a little at least)? some functions are inlines, with a few goto out's inside.. this may have to do with aligning code when it's inlined (no jump to get to the end of the inlined function chunk). schedule() isnt inline though. the source im reading/using is 2.4.14, im not sure if it changes that much, so it may be different already. thanks =) chris -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ IRC Channel: irc.openprojects.net / #kernelnewbies Web Page: http://www.kernelnewbies.org/
