From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>,
Alexander Graf <graf@amazon.com>,
Alexander Duyck <alexander.duyck@gmail.com>,
kvm@vger.kernel.org, mst@redhat.com,
linux-kernel@vger.kernel.org, willy@infradead.org,
mhocko@kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org,
mgorman@techsingularity.net, vbabka@suse.cz, "Van De Ven,
Arjan" <arjan.van.de.ven@intel.com>,
yang.zhang.wz@gmail.com, nitesh@redhat.com, david@redhat.com,
pagupta@redhat.com, riel@surriel.com, lcapitulino@redhat.com,
wei.w.wang@intel.com, aarcange@redhat.com, pbonzini@redhat.com,
dan.j.williams@intel.com, osalvador@suse.de, "Paterson-Jones,
Roland" <rolandp@amazon.com>,
hannes@cmpxchg.org, hare@suse.com, "Boeuf,
Sebastien" <sebastien.boeuf@intel.com>
Subject: Re: [PATCH v16.1 0/9] mm / virtio: Provide support for free page reporting
Date: Thu, 23 Jan 2020 14:23:59 -0500 [thread overview]
Message-ID: <20200123192359.GB11346@char.us.oracle.com> (raw)
In-Reply-To: <21444cdc-76f9-1b06-093e-950cbeb4aa1f@intel.com>
On Thu, Jan 23, 2020 at 09:20:15AM -0800, Dave Hansen wrote:
> On 1/23/20 8:26 AM, Alexander Duyck wrote:
> >> The big piece I'm missing is the page cache. Linux will by default try
> >> to keep the free list as small as it can in favor of page cache, so most
> >> of the benefit of this patch set will be void in real world scenarios.
> > Agreed. This is a the next piece of this I plan to work on once this is
> > accepted. For now the quick and dirty approach is to essentially make use
> > of the /proc/sys/vm/drop_caches interface in the guest by either putting
> > it in a cronjob somewhere or to have it after memory intensive workloads.
>
> There was an implementation in "Clear Linux" that used this sysctl:
>
> > https://github.com/Conan-Kudo/omv-kernel-rc/blob/master/0154-sysctl-vm-Fine-grained-cache-shrinking.patch
>
> (I can't find it in the Clear repos at the moment, must not be used
> currently). But the idea was to have a little daemon in the host that
> periodically applied some artificial pressure with this sysctl. This
> sysctl is a smaller hammer than /proc/sys/vm/drop_caches and lets you
> drop small amounts of cache.
>
> The right way to do it is probably to do real, generic reclaim instead
> of drop_caches.
This sounds like Transcendent Memory (https://www.linux-kvm.org/images/d/d7/TmemNotVirt-Linuxcon2011-Final.pdf)
which has (which is in the Linux kernel) a driver to push on the swapper
and everything else to evict pages to the hypervisor.
Look at cleancache and frontswap and xen-selfballoon.c (was removed by
by 814bbf49dcd0ad642e7ceb8991e57555c5472cce)
Avi Kivity pointed out one big issue with all of this - customers have
to be nicely behaved - which they don't seem to be.
But I would recommend you look at cleancache for the page cache.
>
> This isn't conceptually *that* far away from the "proactive reclaim"
> that other folks have proposed:
>
> https://lwn.net/Articles/787611/
next prev parent reply other threads:[~2020-01-23 19:20 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 17:43 [PATCH v16.1 0/9] mm / virtio: Provide support for free page reporting Alexander Duyck
2020-01-22 17:43 ` [PATCH v16.1 1/9] mm: Adjust shuffle code to allow for future coalescing Alexander Duyck
2020-01-22 17:43 ` [PATCH v16.1 2/9] mm: Use zone and order instead of free area in free_list manipulators Alexander Duyck
2020-01-22 17:43 ` [PATCH v16.1 3/9] mm: Add function __putback_isolated_page Alexander Duyck
2020-01-22 17:43 ` [PATCH v16.1 4/9] mm: Introduce Reported pages Alexander Duyck
2020-01-22 17:43 ` [PATCH v16.1 5/9] virtio-balloon: Pull page poisoning config out of free page hinting Alexander Duyck
2020-01-22 17:43 ` [PATCH v16.1 6/9] virtio-balloon: Add support for providing free page reports to host Alexander Duyck
2020-02-11 11:03 ` David Hildenbrand
2020-02-11 11:47 ` Michael S. Tsirkin
2020-02-11 12:19 ` David Hildenbrand
2020-02-11 14:07 ` Michael S. Tsirkin
2020-02-11 14:31 ` David Hildenbrand
2020-02-11 14:48 ` Michael S. Tsirkin
2020-02-11 15:13 ` David Hildenbrand
2020-02-11 16:33 ` Alexander Duyck
2020-02-11 17:04 ` David Hildenbrand
2020-01-22 17:43 ` [PATCH v16.1 7/9] mm/page_reporting: Rotate reported pages to the tail of the list Alexander Duyck
2020-01-22 17:43 ` [PATCH v16.1 8/9] mm/page_reporting: Add budget limit on how many pages can be reported per pass Alexander Duyck
2020-01-22 17:44 ` [PATCH v16.1 9/9] mm/page_reporting: Add free page reporting documentation Alexander Duyck
2020-01-23 10:20 ` [PATCH v16.1 0/9] mm / virtio: Provide support for free page reporting Alexander Graf
2020-01-23 14:05 ` David Hildenbrand
2020-01-23 14:52 ` Alexander Graf
2020-01-24 13:25 ` David Hildenbrand
2020-01-24 16:20 ` David Hildenbrand
2020-01-23 16:26 ` Alexander Duyck
2020-01-23 16:54 ` Alexander Graf
2020-01-23 18:33 ` Alexander Duyck
2020-01-23 18:47 ` Graf (AWS), Alexander
2020-01-23 22:05 ` Alexander Duyck
2020-01-23 17:20 ` Dave Hansen
2020-01-23 19:23 ` Konrad Rzeszutek Wilk [this message]
2020-01-23 19:17 ` Johannes Weiner
2020-01-23 22:29 ` Alexander Duyck
2020-01-23 23:24 ` Dave Hansen
2020-01-24 13:23 ` Hillf Danton
2020-01-24 16:40 ` Alexander Graf
2020-01-25 2:01 ` Hillf Danton
2020-02-03 22:05 ` Alexander Duyck
2020-02-10 19:18 ` Should I repost? (was: Re: [PATCH v16.1 0/9] mm / virtio: Provide support for free page reporting) Alexander Duyck
2020-02-11 10:40 ` Mel Gorman
2020-02-11 22:57 ` Alexander Duyck
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