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Message-ID: <fa6b575dfea7c2131ecfec0f5578d72ca4acfd95.camel@linux.intel.com>
Subject: Re: [PATCH v5 2/9] mm/demotion: Expose per node memory tier to sysfs
From:   Tim Chen <tim.c.chen@linux.intel.com>
To:     "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        linux-mm@kvack.org, akpm@linux-foundation.org
Cc:     Wei Xu <weixugc@google.com>, Huang Ying <ying.huang@intel.com>,
        Greg Thelen <gthelen@google.com>,
        Yang Shi <shy828301@gmail.com>,
        Davidlohr Bueso <dave@stgolabs.net>,
        Tim C Chen <tim.c.chen@intel.com>,
        Brice Goglin <brice.goglin@gmail.com>,
        Michal Hocko <mhocko@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Hesham Almatary <hesham.almatary@huawei.com>,
        Dave Hansen <dave.hansen@intel.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Alistair Popple <apopple@nvidia.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Feng Tang <feng.tang@intel.com>,
        Jagdish Gediya <jvgediya@linux.ibm.com>,
        Baolin Wang <baolin.wang@linux.alibaba.com>,
        David Rientjes <rientjes@google.com>
Date:   Tue, 07 Jun 2022 13:15:59 -0700
In-Reply-To: <20220603134237.131362-3-aneesh.kumar@linux.ibm.com>
References: <20220603134237.131362-1-aneesh.kumar@linux.ibm.com>
         <20220603134237.131362-3-aneesh.kumar@linux.ibm.com>
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On Fri, 2022-06-03 at 19:12 +0530, Aneesh Kumar K.V wrote:
> 
>  
> +static struct memory_tier *__node_get_memory_tier(int node)
> +{
> +	struct memory_tier *memtier;
> +
> +	list_for_each_entry(memtier, &memory_tiers, list) {

We could need to map node to mem_tier quite often, if we need
to account memory usage at tier level.  It will be more efficient
to have a pointer from node (pgdat) to memtier rather
than doing a search through the list.


> +		if (node_isset(node, memtier->nodelist))
> +			return memtier;
> +	}
> +	return NULL;
> +}
> +
> 

Tim