David Xu wrote: > Matthew Dillon wrote: > >> The main reason we no longer swap the kernel stack is because there >> are >> a whole lot of things we put on local thread stacks that other >> parts of the >> system may reference even while the process is blocked. e.g. token >> references, message structures, register or FP save state, and so >> forth. >> I also intend to put cache related structures, such as range locks, on >> the stack. I just didn't want to have to worry about it. >> >> Besides, it only happened when a process was actually *SWAPPED* >> out, not >> just heavily paged, and how often does *that* happen these days? Even >> on a heavily loaded system only a handful of processes, mostly getty's >> and long-idle interactive shells, might actually be swapped out. This >> makes the memory savings minimal at best. >> >> >> > I always worry about swapping out kernel stack. my lastest kernel umtx > code is broken by this. > I can not agree that per-mutex operation needs a pair of heavy malloc > and free call, if kernel > mutex performance is important, why userland mutex shouldn't be ? If I > have to use malloc, > I am afraid that I have to do more extra work than Linux does, I will > fail under real world > benchmark like super-smack etcs. > Can you provide a reference for the umtx problem? There might be a reasonable solution. ScottReceived on Fri Mar 04 2005 - 00:50:35 UTC
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