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From: Chen Yu <yu.c.chen@intel.com>
To: Reinette Chatre <reinette.chatre@intel.com>
Cc: <tony.luck@intel.com>, <ben.horgan@arm.com>,
	<james.morse@arm.com>, <Dave.Martin@arm.com>,
	<babu.moger@amd.com>, <bp@alien8.de>, <tglx@linutronix.de>,
	<dave.hansen@linux.intel.com>, <x86@kernel.org>, <hpa@zytor.com>,
	<fustini@kernel.org>, <fenghuay@nvidia.com>,
	<peternewman@google.com>, <linux-kernel@vger.kernel.org>,
	<patches@lists.linux.dev>, <chen.yu@linux.dev>
Subject: Re: [PATCH 2/5] x86,fs/resctrl: Remove "arch_needs_linear"
Date: Fri, 4 Sep 2026 11:14:29 +0800	[thread overview]
Message-ID: <apo3lSWAQRRK2W_r@fengwei-dev> (raw)
In-Reply-To: <62904217290f2cd3225d8608c19e284d6dde3aec.1788452481.git.reinette.chatre@intel.com>

Hi Reinette,

On Thu, Sep 03, 2026 at 09:57:04AM -0700, Reinette Chatre wrote:

[ ... ]

>  static __init bool __get_mem_config_intel(struct rdt_resource *r)
>  {
>  	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> @@ -213,16 +192,13 @@ static __init bool __get_mem_config_intel(struct rdt_resource *r)
>  	hw_res->num_closid = edx.split.cos_max + 1;
>  	max_delay = eax.split.max_delay + 1;
>  	r->membw.max_bw = MAX_MBA_BW;
> -	r->membw.arch_needs_linear = true;
> -	if (ecx & MBA_IS_LINEAR) {
> -		r->membw.delay_linear = true;
> -		r->membw.min_bw = MAX_MBA_BW - max_delay;
> -		r->membw.bw_gran = MAX_MBA_BW - max_delay;
> -	} else {
> -		if (!rdt_get_mb_table(r))
> -			return false;
> -		r->membw.arch_needs_linear = false;
> -	}
> +
> +	if (!(ecx & MBA_IS_LINEAR))

Maybe also print the following from rdt_get_mb_table()?
	pr_info("MBA b/w map not implemented for cpu:%d, model:%d",
		boot_cpu_data.x86, boot_cpu_data.x86_model);

In the previous patch, a "Non Linear delay-bw map" warning is triggered
during the actual write operation. Similarly, displaying such a message
during bootup in this patch might also be helpful.

Thanks,
Chenyu

  reply	other threads:[~2026-09-04  3:28 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-03 16:57 [PATCH 0/5] x86,fs/resctrl: Cleanups in preparation for multiple Reinette Chatre
2026-09-03 16:57 ` [PATCH 1/5] fs/resctrl: Drop support for different bandwidth delay mappings Reinette Chatre
2026-09-04  3:33   ` Chen Yu
2026-09-04 15:50     ` Reinette Chatre
2026-09-07  2:08       ` Chen, Yu C
2026-09-03 16:57 ` [PATCH 2/5] x86,fs/resctrl: Remove "arch_needs_linear" Reinette Chatre
2026-09-04  3:14   ` Chen Yu [this message]
2026-09-04 15:50     ` Reinette Chatre
2026-09-07  2:10       ` Chen, Yu C
2026-09-08 16:18         ` Reinette Chatre
2026-09-03 16:57 ` [PATCH 3/5] x86,fs/resctrl: Make MSR_IA32_L{2,3}_QOS_CFG scope architecture specific Reinette Chatre
2026-09-03 16:57 ` [PATCH 4/5] fs/resctrl: Drop unnecessary is_mba_linear() helper Reinette Chatre
2026-09-04  4:38   ` Chen Yu
2026-09-04 15:51     ` Reinette Chatre
2026-09-07  9:15   ` Ben Horgan
2026-09-03 16:57 ` [PATCH 5/5] fs/resctrl: Drop unnecessary parameter from resctrl_io_alloc_parse_line() Reinette Chatre
2026-09-07  9:21   ` Ben Horgan
2026-09-08 16:28     ` Reinette Chatre
2026-09-03 17:02 ` [PATCH 0/5] x86,fs/resctrl: Cleanups in preparation for multiple Reinette Chatre

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