linux-kernel - Re: [PATCH v4 07/12] x86/mtrr: allocate mtrr

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Message-ID: <422b2b56-499e-da5c-b071-7c5f2cd27569@intel.com>
Date:   Mon, 20 Mar 2023 08:31:47 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Juergen Gross <jgross@...e.com>,
        "Huang, Kai" <kai.huang@...el.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>
Cc:     "tglx@...utronix.de" <tglx@...utronix.de>,
        "hpa@...or.com" <hpa@...or.com>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>
Subject: Re: [PATCH v4 07/12] x86/mtrr: allocate mtrr_value array dynamically

On 3/20/23 06:49, Juergen Gross wrote:
>>>
>>> @@ -750,6 +750,7 @@ static int __init mtrr_init_finialize(void)
>>>        * TBD: is there any system with such CPU which supports
>>>        * suspend/resume? If no, we should remove the code.
>>>        */
>>> +    mtrr_value = kcalloc(num_var_ranges, sizeof(*mtrr_value),
>>> GFP_KERNEL);
>>
>> Theoretically dynamic allocation can fail, although it should not
>> happen as this
>> happens during kernel boot and the size is small.  Maybe a WARN()?
> 
> Fine with me.

What *actually* happens if the system is running out of memory and this
is the _first_ failure?  Does a WARN_ON() here help someone debug what
is going on?