linux-kernel - [PATCH] Raise maximum number of memory controllers

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Date:   Tue, 25 Sep 2018 09:34:49 -0500
From:   Justin Ernst <justin.ernst@....com>
To:     Borislav Petkov <bp@...en8.de>
CC:     <russ.anderson@....com>, Justin Ernst <justin.ernst@....com>,
        "Mauro Carvalho Chehab" <mchehab@...nel.org>,
        <linux-edac@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH] Raise maximum number of memory controllers

We observe an oops in the skx_edac module during boot.
Examining /var/log/messages:
[ 3401.985757] EDAC MC0: Giving out device to module skx_edac controller Skylake Socket#0 IMC#0
[ 3401.985887] EDAC MC1: Giving out device to module skx_edac controller Skylake Socket#0 IMC#1
[ 3401.986014] EDAC MC2: Giving out device to module skx_edac controller Skylake Socket#1 IMC#0
...
[ 3401.987318] EDAC MC13: Giving out device to module skx_edac controller Skylake Socket#0 IMC#1
[ 3401.987435] EDAC MC14: Giving out device to module skx_edac controller Skylake Socket#1 IMC#0
[ 3401.987556] EDAC MC15: Giving out device to module skx_edac controller Skylake Socket#1 IMC#1
[ 3401.987579] Too many memory controllers: 16
[ 3402.042614] EDAC MC: Removed device 0 for skx_edac Skylake Socket#0 IMC#0

We observe there are two memory controllers per socket, with a limit of 16.
Raise the maximum number of memory controllers from 16 to 2 * MAX_NUMNODES (1024).

Cc: Borislav Petkov <bp@...en8.de>
Cc: Mauro Carvalho Chehab <mchehab@...nel.org>
Cc: linux-edac@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Acked-by: Russ Anderson <russ.anderson@....com>
Signed-off-by: Justin Ernst <justin.ernst@....com>
---
 include/linux/edac.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/edac.h b/include/linux/edac.h
index bffb97828ed6..958d69332c1d 100644
--- a/include/linux/edac.h
+++ b/include/linux/edac.h
@@ -17,6 +17,7 @@
 #include <linux/completion.h>
 #include <linux/workqueue.h>
 #include <linux/debugfs.h>
+#include <linux/numa.h>

 #define EDAC_DEVICE_NAME_LEN	31

@@ -670,6 +671,6 @@ struct mem_ctl_info {
 /*
  * Maximum number of memory controllers in the coherent fabric.
  */
-#define EDAC_MAX_MCS	16
+#define EDAC_MAX_MCS	2 * MAX_NUMNODES

 #endif
-- 
2.12.3