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From: David Hildenbrand <david@redhat.com>
To: "Wang, Wei W" <wei.w.wang@intel.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"virtualization@lists.linux-foundation.org" 
	<virtualization@lists.linux-foundation.org>
Cc: "tysand@google.com" <tysand@google.com>,
	"mst@redhat.com" <mst@redhat.com>,
	"alexander.h.duyck@linux.intel.com" 
	<alexander.h.duyck@linux.intel.com>,
	"rientjes@google.com" <rientjes@google.com>,
	"mhocko@kernel.org" <mhocko@kernel.org>,
	"namit@vmware.com" <namit@vmware.com>,
	"penguin-kernel@I-love.SAKURA.ne.jp" 
	<penguin-kernel@I-love.SAKURA.ne.jp>
Subject: Re: [PATCH RFC] virtio_balloon: conservative balloon page shrinking
Date: Thu, 6 Feb 2020 10:32:20 +0100	[thread overview]
Message-ID: <80f975c9-5f18-a613-6412-292dafd34dfe@redhat.com> (raw)
In-Reply-To: <286AC319A985734F985F78AFA26841F73E4238BA@shsmsx102.ccr.corp.intel.com>

On 06.02.20 10:28, Wang, Wei W wrote:
> On Thursday, February 6, 2020 5:10 PM, David Hildenbrand wrote:
>> so dropping caches (echo 3 > /proc/sys/vm/drop_caches) will no longer
>> deflate the balloon when conservative_shrinker=true?
>>
> 
> Should be. Need Tyler's help to test it.
> 

If the page cache is empty, a drop_slab() will deflate the whole balloon
if I am not wrong.

Especially, a echo 3 > /proc/sys/vm/drop_caches

will first drop the page cache and then drop_slab()

While I like the general idea, it looks more like a hack to me, to try
to teach the shrinker something it was not built for/does not support yet.

-- 
Thanks,

David / dhildenb


  reply	other threads:[~2020-02-06  9:32 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-06  8:01 Wei Wang
2020-02-06  9:04 ` Michael S. Tsirkin
2020-02-06  9:27   ` Wang, Wei W
2020-02-06  9:31     ` Michael S. Tsirkin
2020-02-06  9:43       ` Wang, Wei W
2020-02-06 11:26         ` Michael S. Tsirkin
2020-02-06  9:09 ` David Hildenbrand
2020-02-06  9:28   ` Wang, Wei W
2020-02-06  9:32     ` David Hildenbrand [this message]
2020-02-06  9:44       ` Wang, Wei W
2020-02-06  9:49         ` David Hildenbrand
2020-02-08 12:32 ` Tetsuo Handa
2020-02-10  3:13   ` Wang, Wei W
2020-02-10  3:57     ` Tetsuo Handa
2020-02-10  7:27       ` Wang, Wei W
2020-02-11 14:18         ` Tetsuo Handa

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