From: Michal Hocko <mhocko@kernel.org>
To: Wei Wang <wei.w.wang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
virtio-dev@lists.oasis-open.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
virtualization <virtualization@lists.linux-foundation.org>,
KVM list <kvm@vger.kernel.org>, linux-mm <linux-mm@kvack.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Paolo Bonzini <pbonzini@redhat.com>,
liliang.opensource@gmail.com, yang.zhang.wz@gmail.com,
quan.xu0@gmail.com, nilal@redhat.com,
Rik van Riel <riel@redhat.com>,
peterx@redhat.com
Subject: Re: [PATCH v35 1/5] mm: support to get hints of free page blocks
Date: Thu, 12 Jul 2018 10:13:17 +0200 [thread overview]
Message-ID: <20180712081317.GD32648@dhcp22.suse.cz> (raw)
In-Reply-To: <5B46C258.40601@intel.com>
On Thu 12-07-18 10:52:08, Wei Wang wrote:
> On 07/12/2018 10:30 AM, Linus Torvalds wrote:
> > On Wed, Jul 11, 2018 at 7:17 PM Wei Wang <wei.w.wang@intel.com> wrote:
> > > Would it be better to remove __GFP_THISNODE? We actually want to get all
> > > the guest free pages (from all the nodes).
> > Maybe. Or maybe it would be better to have the memory balloon logic be
> > per-node? Maybe you don't want to remove too much memory from one
> > node? I think it's one of those "play with it" things.
> >
> > I don't think that's the big issue, actually. I think the real issue
> > is how to react quickly and gracefully to "oops, I'm trying to give
> > memory away, but now the guest wants it back" while you're in the
> > middle of trying to create that 2TB list of pages.
>
> OK. virtio-balloon has already registered an oom notifier
> (virtballoon_oom_notify). I plan to add some control there. If oom happens,
> - stop the page allocation;
> - immediately give back the allocated pages to mm.
Please don't. Oom notifier is an absolutely hideous interface which
should go away sooner or later (I would much rather like the former) so
do not build a new logic on top of it. I would appreciate if you
actually remove the notifier much more.
You can give memory back from the standard shrinker interface. If we are
reaching low reclaim priorities then we are struggling to reclaim memory
and then you can start returning pages back.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2018-07-12 8:13 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-10 9:31 [PATCH v35 0/5] Virtio-balloon: support free page reporting Wei Wang
2018-07-10 9:31 ` [PATCH v35 1/5] mm: support to get hints of free page blocks Wei Wang
2018-07-10 10:16 ` Wang, Wei W
2018-07-10 17:33 ` Linus Torvalds
2018-07-11 1:28 ` Wei Wang
2018-07-11 1:44 ` Linus Torvalds
2018-07-11 9:21 ` Michal Hocko
2018-07-11 10:52 ` Wei Wang
2018-07-11 11:09 ` Michal Hocko
2018-07-11 13:55 ` Wang, Wei W
2018-07-11 14:38 ` Michal Hocko
2018-07-11 19:36 ` Michael S. Tsirkin
2018-07-11 16:23 ` Linus Torvalds
2018-07-12 2:21 ` Wei Wang
2018-07-12 2:30 ` Linus Torvalds
2018-07-12 2:52 ` Wei Wang
2018-07-12 8:13 ` Michal Hocko [this message]
2018-07-12 11:34 ` Wei Wang
2018-07-12 11:49 ` Michal Hocko
2018-07-13 0:33 ` Wei Wang
2018-07-12 13:12 ` Michal Hocko
2018-07-11 4:00 ` Michael S. Tsirkin
2018-07-11 4:04 ` Michael S. Tsirkin
2018-07-10 9:31 ` [PATCH v35 2/5] virtio-balloon: remove BUG() in init_vqs Wei Wang
2018-07-10 9:31 ` [PATCH v35 3/5] virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT Wei Wang
2018-07-10 9:31 ` [PATCH v35 4/5] mm/page_poison: expose page_poisoning_enabled to kernel modules Wei Wang
2018-07-10 9:31 ` [PATCH v35 5/5] virtio-balloon: VIRTIO_BALLOON_F_PAGE_POISON Wei Wang
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