powerpc/mm: Add a parameter to disable 1TB segs
This patch adds the kernel command line parameter "no_tb_segs" which
forces the kernel to use 256MB rather than 1TB segments. Forcing the use
of 256MB segments makes it considerably easier to test code that depends
on an SLB miss occurring.
Suggested-by: Michael Neuling <mikey@neuling.org>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 82b42c9..738bae4 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -920,6 +920,12 @@
dhash_entries= [KNL]
Set number of hash buckets for dentry cache.
+ disable_1tb_segments [PPC]
+ Disables the use of 1TB hash page table segments. This
+ causes the kernel to fall back to 256MB segments which
+ can be useful when debugging issues that require an SLB
+ miss to occur.
+
disable= [IPV6]
See Documentation/networking/ipv6.txt.