linux-kernel - Re: [PATCH v8 10/24] x86/resctrl: Allocate the cleanest CLOSID by searching closid_num_dirty

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Date: Fri, 15 Dec 2023 21:01:37 -0800
From: Reinette Chatre <reinette.chatre@...el.com>
To: James Morse <james.morse@....com>, <x86@...nel.org>,
	<linux-kernel@...r.kernel.org>
CC: Fenghua Yu <fenghua.yu@...el.com>, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, H Peter Anvin
	<hpa@...or.com>, Babu Moger <Babu.Moger@....com>,
	<shameerali.kolothum.thodi@...wei.com>, D Scott Phillips OS
	<scott@...amperecomputing.com>, <carl@...amperecomputing.com>,
	<lcherian@...vell.com>, <bobo.shaobowang@...wei.com>,
	<tan.shaopeng@...itsu.com>, <baolin.wang@...ux.alibaba.com>, Jamie Iles
	<quic_jiles@...cinc.com>, Xin Hao <xhao@...ux.alibaba.com>,
	<peternewman@...gle.com>, <dfustini@...libre.com>, <amitsinght@...vell.com>
Subject: Re: [PATCH v8 10/24] x86/resctrl: Allocate the cleanest CLOSID by
 searching closid_num_dirty_rmid

Hi James,

On 12/15/2023 9:43 AM, James Morse wrote:
> MPAM's PMG bits extend its PARTID space, meaning the same PMG value can be
> used for different control groups.
> 
> This means once a CLOSID is allocated, all its monitoring ids may still be
> dirty, and held in limbo.
> 
> Instead of allocating the first free CLOSID, on architectures where
> CONFIG_RESCTRL_RMID_DEPENDS_ON_CLOSID is enabled, search
> closid_num_dirty_rmid[] to find the cleanest CLOSID.
> 
> The CLOSID found is returned to closid_alloc() for the free list
> to be updated.
> 
> Signed-off-by: James Morse <james.morse@....com>
> Tested-by: Shaopeng Tan <tan.shaopeng@...itsu.com>
> Tested-by: Peter Newman <peternewman@...gle.com>
> Tested-by: Babu Moger <babu.moger@....com>
> Reviewed-by: Shaopeng Tan <tan.shaopeng@...itsu.com>
> Reviewed-by: Reinette Chatre <reinette.chatre@...el.com>
> Reviewed-by: Babu Moger <babu.moger@....com>
> ---
> Changes since v4:
>  * Dropped stale section from comment
> 
> Changes since v5:
>  * Renamed some variables.
> 
> Changes since v7:
>  * Made comments over closid_num_dirty_rmid() not a kdoc comment.

(This is an example of me not relying on you dropping my reviewed-by tag
to take a look at new changes.)

This change is unexpected and does not have anything to do with this patch.
Instead it just seems to undo a change that sneaked into patch #8
of this series.

Reinette