linux-kernel - Re: [RFC 1/5] meminfo: add a per node counter for balloon drivers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAA1CXcBsnbj1toxZNbks+NxrR_R_xuUb76X4ANin551Fi0WROA@mail.gmail.com>
Date: Thu, 13 Mar 2025 11:35:49 -0600
From: Nico Pache <npache@...hat.com>
To: David Hildenbrand <david@...hat.com>
Cc: linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org, 
	virtualization@...ts.linux.dev, xen-devel@...ts.xenproject.org, 
	linux-fsdevel@...r.kernel.org, linux-mm@...ck.org, cgroups@...r.kernel.org, 
	kys@...rosoft.com, haiyangz@...rosoft.com, wei.liu@...nel.org, 
	decui@...rosoft.com, jerrin.shaji-george@...adcom.com, 
	bcm-kernel-feedback-list@...adcom.com, arnd@...db.de, 
	gregkh@...uxfoundation.org, mst@...hat.com, jasowang@...hat.com, 
	xuanzhuo@...ux.alibaba.com, eperezma@...hat.com, jgross@...e.com, 
	sstabellini@...nel.org, oleksandr_tyshchenko@...m.com, 
	akpm@...ux-foundation.org, hannes@...xchg.org, mhocko@...nel.org, 
	roman.gushchin@...ux.dev, shakeel.butt@...ux.dev, muchun.song@...ux.dev, 
	nphamcs@...il.com, yosry.ahmed@...ux.dev, kanchana.p.sridhar@...el.com, 
	alexander.atanasov@...tuozzo.com
Subject: Re: [RFC 1/5] meminfo: add a per node counter for balloon drivers

On Thu, Mar 13, 2025 at 2:22 AM David Hildenbrand <david@...hat.com> wrote:
>
> On 13.03.25 00:04, Nico Pache wrote:
> > On Wed, Mar 12, 2025 at 4:19 PM David Hildenbrand <david@...hat.com> wrote:
> >>
> >> On 12.03.25 01:06, Nico Pache wrote:
> >>> Add NR_BALLOON_PAGES counter to track memory used by balloon drivers and
> >>> expose it through /proc/meminfo and other memory reporting interfaces.
> >>
> >> In balloon_page_enqueue_one(), we perform a
> >>
> >> __count_vm_event(BALLOON_INFLATE)
> >>
> >> and in balloon_page_list_dequeue
> >>
> >> __count_vm_event(BALLOON_DEFLATE);
> >>
> >>
> >> Should we maybe simply do the per-node accounting similarly there?
> >
> > I think the issue is that some balloon drivers use the
> > balloon_compaction interface while others use their own.
> >
> > This would require unifying all the drivers under a single api which
> > may be tricky if they all have different behavior
>
> Why would that be required? Simply implement it in the balloon
> compaction logic, and in addition separately in the ones that don't
> implement it.

Ah ok that makes sense!

>
> That's the same as how we handle PageOffline today.
>
> In summary, we have
>
> virtio-balloon: balloon compaction
> hv-balloon: no balloon compaction
> xen-balloon: no balloon compaction
> vmx-balloon: balloon compaction
> pseries-cmm: balloon compaction

I'm having a hard time verifying this... it looks like only
vmx-balloon uses the balloon_compaction balloon_page_list_enqueue
function that calls balloon_page_enqueue_one.

>
> So you'd handle 3 balloon drivers in one go.
>
> (this series didn't touch pseries-cmm)
Ah I didn't realize that was a balloon driver. Ill add that one to the todo.
>
> --
> Cheers,
>
> David / dhildenb
>