From: "David Hildenbrand (Arm)" <david@kernel.org>
To: Gregory Price <gourry@gourry.net>, "Michael S. Tsirkin" <mst@redhat.com>
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
Subject: Re: [PATCH RFC v2 00/18] mm/virtio: skip redundant zeroing of host-zeroed reported pages
Date: Tue, 21 Apr 2026 12:04:49 +0200 [thread overview]
Message-ID: <0bb2d565-4b3e-4b0b-8e81-57898d8a2a21@kernel.org> (raw)
In-Reply-To: <aebjG-qMLr0joG61@gourry-fedora-PF4VCD3F>
On 4/21/26 04:38, Gregory Price wrote:
> On Mon, Apr 20, 2026 at 07:33:38PM -0400, Michael S. Tsirkin wrote:
>> On Mon, Apr 20, 2026 at 08:20:57PM +0200, David Hildenbrand (Arm) wrote:
>>
>>>
>>> Which would *already* be the case of you use folio_alloc(GFP_ZERO)
>>> instead of magical vma_alloc_folio() + folio_zero_user().
>>>
>>> I don't really see how vma_alloc_folio_hints() -- that also consumes the
>>> address -- is any better in that regard?
>>
>> By itself, it is not. But the issue is propagating the address from
>> there all over mm. If we miss even one place - we get a subtle cache
>> corruption on non x86.
>>
>
> Why does it need to propogate?
>
> Can we leave folio_zero_user() callers the same, but add a PG_zeroed
> check in folio_zero_user() that skips the zeroing (but not the cache
> flush) and clear the PG_zeroed bit?
folio_zero_user() is just an abomination, really.
--
Cheers,
David
next prev parent reply other threads:[~2026-04-21 10:04 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-20 12:51 Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 01/18] mm: page_alloc: propagate PageReported flag across buddy splits Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 02/18] mm: add pghint_t type and vma_alloc_folio_hints API Michael S. Tsirkin
2026-04-21 0:58 ` Huang, Ying
2026-04-20 12:50 ` [PATCH RFC v2 03/18] mm: add PG_zeroed page flag for known-zero pages Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 04/18] mm: page_alloc: track PG_zeroed across buddy merges Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 05/18] mm: page_alloc: preserve PG_zeroed in try_to_claim_block Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 06/18] mm: page_alloc: thread pghint_t through get_page_from_freelist Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 07/18] mm: post_alloc_hook: use PG_zeroed to skip zeroing, return pghint_t Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 08/18] mm: hugetlb: thread pghint_t through buddy allocation chain Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 09/18] mm: hugetlb: use PG_zeroed for pool pages, skip redundant zeroing Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 10/18] mm: page_reporting: support host-zeroed reported pages Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 11/18] mm: skip zeroing in vma_alloc_zeroed_movable_folio for pre-zeroed pages Michael S. Tsirkin
2026-04-21 10:58 ` David Hildenbrand (Arm)
2026-04-21 11:12 ` David Hildenbrand (Arm)
2026-04-21 11:25 ` David Hildenbrand (Arm)
2026-04-20 12:50 ` [PATCH RFC v2 12/18] mm: skip zeroing in alloc_anon_folio " Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 13/18] mm: skip zeroing in vma_alloc_anon_folio_pmd " Michael S. Tsirkin
2026-04-20 12:50 ` [PATCH RFC v2 14/18] mm: memfd: skip zeroing for pre-zeroed hugetlb pages Michael S. Tsirkin
2026-04-20 12:51 ` [PATCH RFC v2 15/18] virtio_balloon: add host_zeroes_pages module parameter Michael S. Tsirkin
2026-04-20 12:51 ` [PATCH RFC v2 16/18] mm: page_reporting: add flush parameter with page budget Michael S. Tsirkin
2026-04-20 12:51 ` [PATCH RFC v2 17/18] mm: add free_frozen_pages_hint and put_page_hint APIs Michael S. Tsirkin
2026-04-21 10:56 ` David Hildenbrand (Arm)
2026-04-20 12:51 ` [PATCH RFC v2 18/18] virtio_balloon: mark deflated pages as pre-zeroed Michael S. Tsirkin
2026-04-20 18:09 ` [syzbot ci] Re: mm/virtio: skip redundant zeroing of host-zeroed reported pages syzbot ci
2026-04-20 18:20 ` [PATCH RFC v2 00/18] " David Hildenbrand (Arm)
2026-04-20 23:33 ` Michael S. Tsirkin
2026-04-21 2:38 ` Gregory Price
2026-04-21 10:04 ` David Hildenbrand (Arm) [this message]
2026-04-21 10:50 ` David Hildenbrand (Arm)
2026-04-21 2:21 ` Gregory Price
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