Re: [PATCH] Raise maximum number of memory controllers

From: Borislav Petkov
Date: Tue Sep 25 2018 - 11:27:00 EST


On Tue, Sep 25, 2018 at 09:34:49AM -0500, Justin Ernst wrote:
> 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).

Tony,

can we read that out from the hardware instead of having this silly
static number?

Leaving in the rest.

> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
> Cc: linux-edac@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Acked-by: Russ Anderson <russ.anderson@xxxxxxx>
> Signed-off-by: Justin Ernst <justin.ernst@xxxxxxx>
> ---
> 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
>

--
Regards/Gruss,
Boris.

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