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From:   Oded Gabbay <oded.gabbay@gmail.com>
Date:   Thu, 10 Mar 2022 13:13:49 +0200
Message-ID: <CAFCwf10NyRmcsDVH+j5B=FDfjquqmDUjYb=Hzn2OUCxOAFE+-w@mail.gmail.com>
Subject: Re: [PATCH v1 00/15] mm: COW fixes part 2: reliable GUP pins of
 anonymous pages
To:     David Hildenbrand <david@redhat.com>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Hugh Dickins <hughd@google.com>,
        David Rientjes <rientjes@google.com>,
        Shakeel Butt <shakeelb@google.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Yang Shi <shy828301@gmail.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Matthew Wilcox <willy@infradead.org>,
        Vlastimil Babka <vbabka@suse.cz>, Jann Horn <jannh@google.com>,
        Michal Hocko <mhocko@kernel.org>,
        Nadav Amit <namit@vmware.com>, Rik van Riel <riel@surriel.com>,
        Roman Gushchin <guro@fb.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Peter Xu <peterx@redhat.com>,
        Donald Dutile <ddutile@redhat.com>,
        Christoph Hellwig <hch@lst.de>,
        Oleg Nesterov <oleg@redhat.com>, Jan Kara <jack@suse.cz>,
        Liang Zhang <zhangliang5@huawei.com>,
        Pedro Gomes <pedrodemargomes@gmail.com>,
        Linux-MM <linux-mm@kvack.org>,
        Khalid Aziz <khalid.aziz@oracle.com>
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On Wed, Mar 9, 2022 at 10:00 AM David Hildenbrand <david@redhat.com> wrote:
>
> On 08.03.22 22:22, Linus Torvalds wrote:
> > On Tue, Mar 8, 2022 at 6:14 AM David Hildenbrand <david@redhat.com> wrote:
> >>
> >> This series fixes memory corruptions when a GUP pin (FOLL_PIN) was taken
> >> on an anonymous page and COW logic fails to detect exclusivity of the page
> >> to then replacing the anonymous page by a copy in the page table [...]
> >
> > From a cursory scan of the patches, this looks sane.
>
> Thanks for skimming over the patches that quickly!
>
> >
> > I'm not sure what the next step should be, but I really would like the
> > people who do a lot of pinning stuff to give it a good shake-down.
> > Including both looking at the patches, but very much actually running
> > it on whatever test-cases etc you people have.
> >
> > Please?

I can take this patch-set and test it in our data-center with all the
DL workloads we are running
on Gaudi.

David,
Any chance you can prepare me a branch with your patch-set based on 5.17-rc7 ?
I prefer to take a stable kernel and not 5.18-rc1 as this is going to
run on hundreds of machines.

Thanks,
Oded

>
> My proposal would be to pull it into -next early after we have
> v5.18-rc1. I expect some minor clashes with folio changes that should go
> in in the next merge window, so I'll have to rebase+resend either way,
> and I'm planning on thoroughly testing at least on s390x as well.
>
> We'd then have plenty of time to further review+test while in -next
> until the v5.19 merge window opens up.
>
> By that time I should also have my selftests cleaned up and ready, and
> part 3 ready to improve the situation for FOLL_GET|FOLL_WRITE until we
> have the full FOLL_GET->FOLL_PIN conversion from John (I'll most
> probably sent out an early RFC of part 3 soonish). So we *might* be able
> to have everything fixed in v5.19.
>
> Last but not least, tools/cgroup/memcg_slabinfo.py as mentioned in patch
> #10 still needs care due to the PG_slab reuse, but I consider that a
> secondary concern (yet, it should be fixed and help from the Authors
> would be appreciated ;) ).
>
> --
> Thanks,
>
> David / dhildenb
>