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Date:   Mon, 7 Feb 2022 11:18:04 -0500
From:   Johannes Weiner <hannes@cmpxchg.org>
To:     Huang Ying <ying.huang@intel.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Mel Gorman <mgorman@suse.de>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, Feng Tang <feng.tang@intel.com>,
        Yang Shi <shy828301@gmail.com>,
        Baolin Wang <baolin.wang@linux.alibaba.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>,
        Rik van Riel <riel@surriel.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Zi Yan <ziy@nvidia.com>, Wei Xu <weixugc@google.com>,
        osalvador <osalvador@suse.de>,
        Shakeel Butt <shakeelb@google.com>,
        zhongjiang-ali <zhongjiang-ali@linux.alibaba.com>
Subject: Re: [PATCH -V11 1/3] NUMA Balancing: add page promotion counter
Message-ID: <YgFGPMCfWb8CK5mn@cmpxchg.org>
References: <20220128082751.593478-1-ying.huang@intel.com>
 <20220128082751.593478-2-ying.huang@intel.com>
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On Fri, Jan 28, 2022 at 04:27:49PM +0800, Huang Ying wrote:
> In a system with multiple memory types, e.g. DRAM and PMEM, the CPU
> and DRAM in one socket will be put in one NUMA node as before, while
> the PMEM will be put in another NUMA node as described in the
> description of the commit c221c0b0308f ("device-dax: "Hotplug"
> persistent memory for use like normal RAM").  So, the NUMA balancing
> mechanism will identify all PMEM accesses as remote access and try to
> promote the PMEM pages to DRAM.
> 
> To distinguish the number of the inter-type promoted pages from that
> of the inter-socket migrated pages.  A new vmstat count is added.  The
> counter is per-node (count in the target node).  So this can be used
> to identify promotion imbalance among the NUMA nodes.
> 
> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
> Reviewed-by: Yang Shi <shy828301@gmail.com>
> Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Rik van Riel <riel@surriel.com>
> Cc: Mel Gorman <mgorman@techsingularity.net>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: Wei Xu <weixugc@google.com>
> Cc: osalvador <osalvador@suse.de>
> Cc: Shakeel Butt <shakeelb@google.com>
> Cc: zhongjiang-ali <zhongjiang-ali@linux.alibaba.com>
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-mm@kvack.org

Acked-by: Johannes Weiner <hannes@cmpxchg.org>