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

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Date:   Tue, 25 Sep 2018 17:26:59 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Tony Luck <tony.luck@...el.com>
Cc:     Justin Ernst <justin.ernst@....com>, russ.anderson@....com,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        linux-edac@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Raise maximum number of memory controllers

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@...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
> 

-- 
Regards/Gruss,
    Boris.

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