linux-kernel - Re: [PATCH v3 30/47] arm_mpam: resctrl: Pre-allocate free running monitors

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Message-ID: <a25b6768-2423-48d8-aabf-fc902199ffbc@arm.com>
Date: Mon, 19 Jan 2026 20:27:48 +0000
From: Ben Horgan <ben.horgan@....com>
To: Gavin Shan <gshan@...hat.com>
Cc: amitsinght@...vell.com, baisheng.gao@...soc.com,
 baolin.wang@...ux.alibaba.com, carl@...amperecomputing.com,
 dave.martin@....com, david@...nel.org, dfustini@...libre.com,
 fenghuay@...dia.com, james.morse@....com, jonathan.cameron@...wei.com,
 kobak@...dia.com, lcherian@...vell.com,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
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 quic_jiles@...cinc.com, reinette.chatre@...el.com, rohit.mathew@....com,
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 joey.gouly@....com, suzuki.poulose@....com, kvmarm@...ts.linux.dev
Subject: Re: [PATCH v3 30/47] arm_mpam: resctrl: Pre-allocate free running
 monitors

Hi Gavin,

On 1/19/26 11:57, Gavin Shan wrote:
> Hi Ben,
> 
> On 1/13/26 12:58 AM, Ben Horgan wrote:
>> From: James Morse <james.morse@....com>
>>
>> When there are enough monitors, the resctrl mbm local and total files can
>> be exposed. These need all the monitors that resctrl may use to be
>> allocated up front.
>>
>> Add helpers to do this.
>>
>> If a different candidate class is discovered, the old array should be
>> free'd and the allocated monitors returned to the driver.
>>
>> Signed-off-by: James Morse <james.morse@....com>
>> Signed-off-by: Ben Horgan <ben.horgan@....com>

>> +
>> +static int *__alloc_mbwu_array(struct mpam_class *class, u16
>> num_mbwu_mon)
>> +{
>> +    int err;
>> +    size_t array_size = num_mbwu_mon * sizeof(int);
>> +    int *array __free(kfree) = kmalloc(array_size, GFP_KERNEL);
>> +
> 
> A warning reported by checkpatch.pl as below.
> 
> WARNING: Missing a blank line after declarations
> #84: FILE: drivers/resctrl/mpam_resctrl.c:607:
> +    size_t array_size = num_mbwu_mon * sizeof(int);
> +    int *array __free(kfree) = kmalloc(array_size, GFP_KERNEL);
> 

Similarly to the other blank line checkpatch.pl warning I expect this is
to do with how it handles the __free() annotation. I'm not intending to
change this code unless there is some style guideline that I've missed
or other reason to do so.

Thanks,

Ben