On Thu, Jun 24, 2004 at 13:00:10 -0700, l x wrote: > Thanks for the information. It helps. > > Sounds to me like, we can completely disable > preemption (time sharing feature) of lk 2.6 and then > lk 2.6 will act like lk 2.4? > > How/where/when can we use: > > preempt_disable() > preempt_enable() > get_cpu() > put_cpu() > > on lk 2.6 to change it to a non-preemptive OS? Google > only gives me one search result for preempt_disable. Preemption is equivalent to SMP and every code in linux kernel must work on SMP too (remember that hyperthreading is SMP and that is rather common in new CPUs). So you don't want to preempt_disable/enable manualy. They are part of spinlock and irq disabling macros. Since every code, that needs disabled preemption also needs mutual exclusion on SMP, you should be using spinlocks, which do the right thing. ------------------------------------------------------------------------------- Jan 'Bulb' Hudec <bulb@ucw.cz>
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