From: Dean Roe <roe@sgi.com>
Date: Thu, 27 Oct 2005 20:41:04 +0000 (-0500)
Subject: [IA64] - Avoid slow TLB purges on SGI Altix systems
X-Git-Tag: v2.6.15-rc1~731^2~16^2^2~3^2
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c1902aae322952f8726469a6657df7b9d5c794fe;p=pandora-kernel.git

[IA64] - Avoid slow TLB purges on SGI Altix systems

flush_tlb_all() can be a scaling issue on large SGI Altix systems
since it uses the global call_lock and always executes on all cpus.
When a process enters flush_tlb_range() to purge TLBs for another
process, it is possible to avoid flush_tlb_all() and instead allow
sn2_global_tlb_purge() to purge TLBs only where necessary.

This patch modifies flush_tlb_range() so that this case can be handled
by platform TLB purge functions and updates ia64_global_tlb_purge()
accordingly.  sn2_global_tlb_purge() now calculates the region register
value from the mm argument introduced with this patch.

Signed-off-by: Dean Roe <roe@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
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