Shrinking the x86 stack

Shrinking the x86 stack

I can't comment on other architectures, but on the x86, the 8 KB (2 page)
area actually has two purposes. It contains the (fixed-size) task_struct
at the bottom end, and the kernel stack growing down from the top end.

On x86, the pseudo-variable "current" which points to the current process's
task_struct is actually an assembly macro which does (roughly)

%esp & ~8KB

The observation is that since every process has an 8 KB block, aligned
to 8 KB, to find the address of task_struct, one just needs to round down
the stack pointer to the nearest 8 KB-aligned address.

This article didn't make clear what happened to task_struct. Is it still
there? Or somewhere else?