Re: [PATCH v6 0/9] Multigenerational LRU Framework

From: Yu Zhao <yuzhao@google.com>
To: Donald Carr <d@chaos-reins.com>
Cc: Andi Kleen <ak@linux.intel.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Hillf Danton <hdanton@sina.com>, Jens Axboe <axboe@kernel.dk>,
	Jesse Barnes <jsbarnes@google.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Jonathan Corbet <corbet@lwn.net>,
	Matthew Wilcox <willy@infradead.org>,
	Mel Gorman <mgorman@suse.de>,
	Michael Larabel <Michael@michaellarabel.com>,
	Michal Hocko <mhocko@kernel.org>, Rik van Riel <riel@surriel.com>,
	Vlastimil Babka <vbabka@suse.cz>, Will Deacon <will@kernel.org>,
	Ying Huang <ying.huang@intel.com>,
	linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	page-reclaim@google.com, x86@kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v6 0/9] Multigenerational LRU Framework
Date: Tue, 18 Jan 2022 02:21:21 -0700	[thread overview]
Message-ID: <YeaGkZ50n7/mDuJX@google.com> (raw)
In-Reply-To: <Yd1Css8+jsspeZHh@google.com>

On Tue, Jan 11, 2022 at 01:41:22AM -0700, Yu Zhao wrote:
> On Tue, Jan 04, 2022 at 01:30:00PM -0700, Yu Zhao wrote:
> > On Tue, Jan 04, 2022 at 01:22:19PM -0700, Yu Zhao wrote:
> > > TLDR
> > > ====
> > > The current page reclaim is too expensive in terms of CPU usage and it
> > > often makes poor choices about what to evict. This patchset offers an
> > > alternative solution that is performant, versatile and
> > > straightforward.
> > 
> > <snipped>
> > 
> > > Summery
> > > =======
> > > The facts are:
> > > 1. The independent lab results and the real-world applications
> > >    indicate substantial improvements; there are no known regressions.
> > > 2. Thrashing prevention, working set estimation and proactive reclaim
> > >    work out of the box; there are no equivalent solutions.
> > > 3. There is a lot of new code; nobody has demonstrated smaller changes
> > >    with similar effects.
> > > 
> > > Our options, accordingly, are:
> > > 1. Given the amount of evidence, the reported improvements will likely
> > >    materialize for a wide range of workloads.
> > > 2. Gauging the interest from the past discussions [14][15][16], the
> > >    new features will likely be put to use for both personal computers
> > >    and data centers.
> > > 3. Based on Google's track record, the new code will likely be well
> > >    maintained in the long term. It'd be more difficult if not
> > >    impossible to achieve similar effects on top of the existing
> > >    design.
> > 
> > Hi Andrew, Linus,
> > 
> > Can you please take a look at this patchset and let me know if it's
> > 5.17 material?
> > 
> > My goal is to get it merged asap so that users can reap the benefits
> > and I can push the sequels. Please examine the data provided -- I
> > think the unprecedented coverage and the magnitude of the improvements
> > warrant a green light.

My gratitude to Donald who has been helping test MGLRU since v2:

    Donald Carr (d@chaos-reins.com)

    Founder of Chaos Reins (http://chaos-reins.com), an SF based
    consultancy company specializing in designing/creating embedded
    Linux appliances.

Can you please provide your Tested-by tags? This will ensure the credit
for your contributions.

Thanks!