> There appear to be, in sched.h, in struct task, a few SMP related fields.
> If these are indeed only needed in SMP operation, wouldn't it be best to
> surround them with a "#ifdef __SMP__"?
>
> This would save a couple of pages(!) RAM in 2.1.x for the default NR_TASKS
> == 512.
It wouldn't, struct task_struct is allocated as part of the process'
kernel stack. What could be done is sorting things such that only SMP
machines will ever fetch elements only used for SMP into the cache.
Someone else was already thinking about that some time ago.
Ralf