On Tue, Mar 05, 2002 at 02:19:37PM +0530, Anurekh Saxena wrote:
> hi,
> could you tell me the role of "last" in the switch_to macro.
> schedule() sends 'prev' as this parameter to so it could be used by
> schedule_tail().
> I would like to know how 'prev' (i.e 'last' in switch_to) is different from
> 'current', and how last is used in switch_to.
You're looking at
#define switch_to(prev,next,last) ...
from 2.4.
The last parameter in switch_to() is redundant and has been removed
in 2.5. It obfuscates switch_to() in 2.4. Looking at the (sole) call
of switch_to() in the 2.4 (or any other) kernel, we have:
...
/*
* This just switches the register state and the
* stack.
*/
switch_to(prev, next, prev);
__schedule_tail(prev);
same_process:
...
This has been cleaned up in 2.5.
Cheers,
Bill
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