From debddd95ec0bb8ac1bbe719b5e4588e453c7b2fc Mon Sep 17 00:00:00 2001
From: LEROY Christophe <christophe.leroy@c-s.fr>
Date: Mon, 19 Jan 2015 16:44:42 +0100
Subject: [PATCH] powerpc/8xx: reduce pressure on TLB due to context switches

For nohash powerpc, when we run out of contexts, contexts are freed by stealing
used contexts in-turn. When a victim has been selected, the associated TLB
entries are freed using _tlbil_pid(). Unfortunatly, on the PPC 8xx, _tlbil_pid()
does a tlbia, hence flushes ALL TLB entries and not only the one linked to the
stolen context. Therefore, as implented today, at each task switch requiring a
new context, all entries are flushed.

This patch modifies the implementation so that when running out of contexts, all
contexts get freed at once, hence dividing the number of calls to tlbia by 16.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <scottwood@freescale.com>
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