> DEFINE(IA64_UPID_SHIFT, 5);
>
> Grepping for IA64_UPID_SHIFT leads us to some assembly
> code implementing fsys_getpid (why is that in assembly?!):
The fast system call path has a whole host of serious restrictions on what it can
touch. See Documentation/ia64/fsys.txt. Why is getpid() a fast system call? I think
there was some application (or perhaps benchmark) that used it a lot.
> add r8=IA64_PID_LEVEL_OFFSET,r17
> ;;
> ld4 r8=[r8] // r8 = pid->level
> add r17=IA64_PID_UPID_OFFSET,r17 // r17 = &pid->numbers[0]
> ;;
> shl r8=r8,IA64_UPID_SHIFT
> ;;
> add r17=r17,r8 // r17 = &pid->numbers[pid->level]
> ;;
> ld4 r8=[r17] // r8 = pid->numbers[pid->level].nr
> ;;
> mov r17=0
>
> Luckily it looks like this is only referencing the first members of struct upid,
> and you are removing the last member, so I suspect you will be fine changing the IA64
> to this:
>
> BUILD_BUG_ON(sizeof(struct upid) != 16);
> DEFINE(IA64_UPID_SHIFT, 4);
>
> Tony, does that look ok to you?
I think so. Respin and Cc: me on both patches in the series and I'll take it for a spin
on h/w to make sure.
-Tony
��.n��������+%������w��{.n�����{��&�����ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
|