From: Dave Hansen <dave.hansen@intel.com>
To: Johannes Weiner <hannes@cmpxchg.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
"Huang, Ying" <ying.huang@intel.com>,
Yang Shi <yang.shi@linux.alibaba.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com,
Zi Yan <ziy@nvidia.com>, Michal Hocko <mhocko@suse.com>,
Shakeel Butt <shakeelb@google.com>, Roman Gushchin <guro@fb.com>
Subject: Re: [PATCH] Revert "mm/vmscan: never demote for memcg reclaim"
Date: Wed, 18 May 2022 12:51:10 -0700 [thread overview]
Message-ID: <afd96793-549d-94eb-607c-6a785788397a@intel.com> (raw)
In-Reply-To: <20220518190911.82400-1-hannes@cmpxchg.org>
On 5/18/22 12:09, Johannes Weiner wrote:
> However, with NUMA balancing now doing tier promotions, demotion is
> part of the page aging process. Global reclaim demotes the coldest
> toptier pages to secondary memory, where their life continues and from
> which they have a chance to get promoted back. Essentially, tiered
> memory systems have an LRU order that spans multiple nodes.
Thanks for the detailed explanation. Ultimately, this was just intended
as an optimization to make cgroup reclaim more efficient. But, I agree
that ordering correctness should trump efficiency.
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
next prev parent reply other threads:[~2022-05-18 19:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-18 19:09 [PATCH] Revert "mm/vmscan: never demote for memcg reclaim" Johannes Weiner
2022-05-18 19:51 ` Dave Hansen [this message]
2022-05-18 20:42 ` Yang Shi
2022-05-18 21:50 ` Roman Gushchin
2022-05-19 5:11 ` Shakeel Butt
2022-05-19 7:42 ` ying.huang
2022-05-23 18:59 ` Tim Chen
2022-05-19 8:53 ` Muchun Song
2022-05-19 9:51 ` Michal Hocko
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