From: "Michael S. Tsirkin" <mst@redhat.com>
To: "David Hildenbrand (Arm)" <david@kernel.org>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@kernel.org>,
Brendan Jackman <jackmanb@google.com>,
Michal Hocko <mhocko@suse.com>,
Suren Baghdasaryan <surenb@google.com>,
Jason Wang <jasowang@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-mm@kvack.org, virtualization@lists.linux.dev,
Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Mike Rapoport <rppt@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>, Zi Yan <ziy@nvidia.com>
Subject: Re: [PATCH RFC 2/9] mm: page_reporting: skip redundant zeroing of host-zeroed reported pages
Date: Tue, 14 Apr 2026 11:36:25 -0400 [thread overview]
Message-ID: <20260414113505-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <8900872f-39e1-44ab-8440-e91ce3f0523a@kernel.org>
On Tue, Apr 14, 2026 at 05:32:16PM +0200, David Hildenbrand (Arm) wrote:
> On 4/14/26 12:22, Michael S. Tsirkin wrote:
> > On Tue, Apr 14, 2026 at 11:18:02AM +0200, David Hildenbrand (Arm) wrote:
> >> On 4/13/26 22:35, Michael S. Tsirkin wrote:
> >>>
> >>>
> >>> So here's an only alternative I see: a page flag for when page is in
> >>> buddy and a new "prezero" bool that we have to propagate everywhere
> >>> else. This is a patch on top. More elegant? Please tell me if you prefer that.
> >>> If yes I will squash it into the appropriate patches.
> >>
> >> I'd be interesting to know how this would look without the GFP flag,
> >> when we don't have to leak any of this out of the buddy.
> >>
> >> --
> >> Cheers,
> >>
> >> David
> >
> > But the zeroing takes place outside of the buddy now, it's more
> > "reporting" than "leaking".
>
> Exposing some buddy internals using questionable GFP flags, however you
> want to call that hack ;)
>
> >
> > You mean, moving the zeroing into buddy?
>
> Yes. Such that it doesn't really matter how we maintain this information
> internally. A page flag is probably still nicer for that purpose.
OK, sure. Let me just finish testing, and I will post.
--
MST
next prev parent reply other threads:[~2026-04-14 15:36 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-12 22:50 [PATCH RFC 0/9] mm/virtio: skip redundant zeroing of host-zeroed reported pages Michael S. Tsirkin
2026-04-12 22:50 ` [PATCH RFC 1/9] mm: page_alloc: propagate PageReported flag across buddy splits Michael S. Tsirkin
2026-04-13 19:11 ` David Hildenbrand (Arm)
2026-04-13 20:32 ` Michael S. Tsirkin
2026-04-14 9:08 ` David Hildenbrand (Arm)
2026-04-12 22:50 ` [PATCH RFC 2/9] mm: page_reporting: skip redundant zeroing of host-zeroed reported pages Michael S. Tsirkin
2026-04-13 8:00 ` David Hildenbrand (Arm)
2026-04-13 8:10 ` Michael S. Tsirkin
2026-04-13 8:15 ` David Hildenbrand (Arm)
2026-04-13 8:29 ` Michael S. Tsirkin
2026-04-13 20:35 ` Michael S. Tsirkin
2026-04-14 9:18 ` David Hildenbrand (Arm)
2026-04-14 10:22 ` Michael S. Tsirkin
2026-04-14 15:32 ` David Hildenbrand (Arm)
2026-04-14 15:36 ` Michael S. Tsirkin [this message]
2026-04-12 22:50 ` [PATCH RFC 3/9] mm: add __GFP_PREZEROED flag and folio_test_clear_prezeroed() Michael S. Tsirkin
2026-04-13 9:05 ` David Hildenbrand (Arm)
2026-04-13 20:37 ` Michael S. Tsirkin
2026-04-14 9:04 ` David Hildenbrand (Arm)
2026-04-14 10:29 ` Michael S. Tsirkin
2026-04-14 15:46 ` David Hildenbrand (Arm)
2026-04-16 8:45 ` Michael S. Tsirkin
2026-04-13 21:37 ` Michael S. Tsirkin
2026-04-13 22:06 ` Michael S. Tsirkin
2026-04-13 23:43 ` Michael S. Tsirkin
2026-04-14 9:06 ` David Hildenbrand (Arm)
2026-04-12 22:50 ` [PATCH RFC 4/9] mm: skip zeroing in vma_alloc_zeroed_movable_folio for pre-zeroed pages Michael S. Tsirkin
2026-04-12 22:50 ` [PATCH RFC 5/9] mm: skip zeroing in alloc_anon_folio " Michael S. Tsirkin
2026-04-12 22:50 ` [PATCH RFC 6/9] mm: skip zeroing in vma_alloc_anon_folio_pmd " Michael S. Tsirkin
2026-04-12 22:51 ` [PATCH RFC 7/9] mm: hugetlb: skip zeroing of pre-zeroed hugetlb pages Michael S. Tsirkin
2026-04-12 22:51 ` [PATCH RFC 8/9] mm: page_reporting: add flush parameter to trigger immediate reporting Michael S. Tsirkin
2026-04-12 22:51 ` [PATCH RFC 9/9] virtio_balloon: a hack to enable host-zeroed page optimization Michael S. Tsirkin
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