From: Yu Zhao <yuzhao@google.com>
To: Rik van Riel <riel@surriel.com>, Ying Huang <ying.huang@intel.com>
Cc: Dave Chinner <david@fromorbit.com>, Jens Axboe <axboe@kernel.dk>,
SeongJae Park <sj38.park@gmail.com>,
Linux-MM <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Benjamin Manes <ben.manes@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Hillf Danton <hdanton@sina.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Jonathan Corbet <corbet@lwn.net>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Matthew Wilcox <willy@infradead.org>,
Mel Gorman <mgorman@suse.de>, Miaohe Lin <linmiaohe@huawei.com>,
Michael Larabel <michael@michaellarabel.com>,
Michal Hocko <mhocko@suse.com>,
Michel Lespinasse <michel@lespinasse.org>,
Roman Gushchin <guro@fb.com>, Rong Chen <rong.a.chen@intel.com>,
SeongJae Park <sjpark@amazon.de>,
Tim Chen <tim.c.chen@linux.intel.com>,
Vlastimil Babka <vbabka@suse.cz>, Yang Shi <shy828301@gmail.com>,
Zi Yan <ziy@nvidia.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
lkp@lists.01.org,
Kernel Page Reclaim v2 <page-reclaim@google.com>,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH v2 00/16] Multigenerational LRU Framework
Date: Thu, 15 Apr 2021 01:13:13 -0600 [thread overview]
Message-ID: <CAOUHufaAz72+0HJu=XPv-6T8rUAdYo_mb5=H+yF3=LfwoufeYg@mail.gmail.com> (raw)
In-Reply-To: <20210415030002.GX3762101@tassilo.jf.intel.com>
On Wed, Apr 14, 2021 at 9:00 PM Andi Kleen <ak@linux.intel.com> wrote:
>
> > We fall back to the rmap when it's obviously not smart to do so. There
> > is still a lot of room for improvement in this function though, i.e.,
> > it should be per VMA and NUMA aware.
>
> Okay so it's more a question to tune the cross over heuristic. That
> sounds much easier than replacing everything.
>
> Of course long term it might be a problem to maintain too many
> different ways to do things, but I suppose short term it's a reasonable
> strategy.
Hi Rik, Ying,
Sorry for being persistent. I want to make sure we are on the same page:
Page table scanning doesn't replace the existing rmap walk. It is
complementary and only happens when it is likely that most of the
pages on a system under pressure have been referenced, i.e., out of
*inactive* pages, by definition of the existing implementation. Under
such a condition, scanning *active* pages one by one with the rmap is
likely to cost more than scanning them all at once via page tables.
When we evict *inactive* pages, we still use the rmap and share a
common path with the existing code.
Page table scanning falls back to the rmap walk if the page tables of
a process are apparently sparse, i.e., rss < size of the page tables.
I should have clarified this at the very beginning of the discussion.
But it has become so natural to me and I assumed we'd all see it this
way.
Your concern regarding the NUMA optimization is still valid, and it's
a high priority.
Thanks.
next prev parent reply other threads:[~2021-04-15 7:13 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 6:56 [PATCH v2 00/16] Multigenerational LRU Framework Yu Zhao
2021-04-13 6:56 ` [PATCH v2 01/16] include/linux/memcontrol.h: do not warn in page_memcg_rcu() if !CONFIG_MEMCG Yu Zhao
2021-04-13 6:56 ` [PATCH v2 02/16] include/linux/nodemask.h: define next_memory_node() if !CONFIG_NUMA Yu Zhao
2021-04-13 6:56 ` [PATCH v2 03/16] include/linux/huge_mm.h: define is_huge_zero_pmd() if !CONFIG_TRANSPARENT_HUGEPAGE Yu Zhao
2021-04-13 6:56 ` [PATCH v2 04/16] include/linux/cgroup.h: export cgroup_mutex Yu Zhao
2021-04-13 6:56 ` [PATCH v2 05/16] mm/swap.c: export activate_page() Yu Zhao
2021-04-13 6:56 ` [PATCH v2 06/16] mm, x86: support the access bit on non-leaf PMD entries Yu Zhao
2021-04-13 6:56 ` [PATCH v2 07/16] mm/vmscan.c: refactor shrink_node() Yu Zhao
2021-04-13 6:56 ` [PATCH v2 08/16] mm: multigenerational lru: groundwork Yu Zhao
2021-04-13 6:56 ` [PATCH v2 09/16] mm: multigenerational lru: activation Yu Zhao
2021-04-13 6:56 ` [PATCH v2 10/16] mm: multigenerational lru: mm_struct list Yu Zhao
2021-04-14 14:36 ` Matthew Wilcox
2021-04-13 6:56 ` [PATCH v2 11/16] mm: multigenerational lru: aging Yu Zhao
2021-04-13 6:56 ` [PATCH v2 12/16] mm: multigenerational lru: eviction Yu Zhao
2021-04-13 6:56 ` [PATCH v2 13/16] mm: multigenerational lru: page reclaim Yu Zhao
2021-04-13 6:56 ` [PATCH v2 14/16] mm: multigenerational lru: user interface Yu Zhao
2021-04-13 6:56 ` [PATCH v2 15/16] mm: multigenerational lru: Kconfig Yu Zhao
2021-04-13 6:56 ` [PATCH v2 16/16] mm: multigenerational lru: documentation Yu Zhao
2021-04-13 7:51 ` [PATCH v2 00/16] Multigenerational LRU Framework SeongJae Park
2021-04-13 16:13 ` Jens Axboe
2021-04-13 16:42 ` SeongJae Park
2021-04-13 23:14 ` Dave Chinner
2021-04-14 2:29 ` Rik van Riel
[not found] ` <CAOUHufafMcaG8sOS=1YMy2P_6p0R1FzP16bCwpUau7g1-PybBQ@mail.gmail.com>
2021-04-14 6:15 ` Huang, Ying
2021-04-14 7:58 ` Yu Zhao
2021-04-14 8:27 ` Huang, Ying
2021-04-14 13:51 ` Rik van Riel
2021-04-14 15:56 ` Andi Kleen
2021-04-14 15:58 ` [page-reclaim] " Shakeel Butt
2021-04-14 18:45 ` Yu Zhao
2021-04-14 15:51 ` Andi Kleen
2021-04-14 15:58 ` Rik van Riel
2021-04-14 19:14 ` Yu Zhao
2021-04-14 19:41 ` Rik van Riel
2021-04-14 20:08 ` Yu Zhao
2021-04-14 19:04 ` Yu Zhao
2021-04-15 3:00 ` Andi Kleen
2021-04-15 7:13 ` Yu Zhao [this message]
2021-04-15 8:19 ` Huang, Ying
2021-04-15 9:57 ` Michel Lespinasse
2021-04-24 2:33 ` Yu Zhao
2021-04-24 3:30 ` Andi Kleen
2021-04-24 4:16 ` Yu Zhao
2021-04-14 3:40 ` Yu Zhao
2021-04-14 4:50 ` Dave Chinner
2021-04-14 7:16 ` Yu Zhao
2021-04-14 10:00 ` Yu Zhao
2021-04-15 1:36 ` Dave Chinner
2021-04-24 21:21 ` Yu Zhao
2021-04-14 14:43 ` Jens Axboe
2021-04-14 19:42 ` Yu Zhao
2021-04-15 1:21 ` Dave Chinner
2021-04-14 17:43 ` Johannes Weiner
2021-04-27 10:35 ` Yu Zhao
2021-04-29 23:46 ` Konstantin Kharlamov
2021-04-30 6:37 ` Konstantin Kharlamov
2021-04-30 19:31 ` Yu Zhao
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