RE: [Linux-ia64] SMP TLB flushes

["Rao, Goutham" <goutham.rao@intel.com>]

Hi,
ptc.g gets RID from bits 63:61 of the address used in the purge instruction.

Thanks
Goutham

-----Original Message-----
From: Manfred Spraul [mailto:manfred@colorfullife.com]
Sent: Thursday, August 31, 2000 10:57 AM
To: linux-ia64@linuxia64.org
Subject: [Linux-ia64] SMP TLB flushes


Is it correct that the SMP part of the SMP flushing code is still
missing? I'm just noisy and I don't understand yet how the ia64 cpu is
supposed to perform tlb flushes.

* ptc.g only gets the address and the size as parameters, but not a
region id. What if cpu 1 (running kswapd, arbitrary thread context)
wants to flush a page from another thread, and that thread is running on
cpu 2?

* could you add a big warning to start_lazy_tlb [kernel/exit.c] that the
function is unsafe?
Both ppc and ia64 scan the task list and assume that they can find each
mm_struct. If someone actually uses start_lazy_tlb, then that would be
incorrect.

Btw, the i386 tlb flush contained a single instruction race (read x,
write y instead of write y, read x) and this was enough for corruptions
- I overlooked one problem with concurrent tlb flushes and thread
switches.

Please cc me, I'm not subscribed to the list.

--
	Manfred

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