From: Mike Kravetz <mike.kravetz@oracle.com>
To: James Houghton <jthoughton@google.com>
Cc: Junxiao Chang <junxiao.chang@intel.com>,
akpm@linux-foundation.org, kirill.shutemov@linux.intel.com,
mhocko@suse.com, jmarchan@redhat.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, muchun.song@linux.dev
Subject: Re: [PATCH] mm: fix hugetlb page unmap count balance issue
Date: Fri, 12 May 2023 16:29:47 -0700 [thread overview]
Message-ID: <20230512232947.GA3927@monkey> (raw)
In-Reply-To: <CADrL8HV25JyeaT=peaR7NWhUiaBz8LzpyFosYZ3_0ACt+twU6w@mail.gmail.com>
On 05/12/23 14:26, James Houghton wrote:
> On Fri, May 12, 2023 at 12:20 AM Junxiao Chang <junxiao.chang@intel.com> wrote:
>
> This alone doesn't fix mapcounting for PTE-mapped HugeTLB pages. You
> need something like [1]. I can resend it if that's what we should be
> doing, but this mapcounting scheme doesn't work when the page structs
> have been freed.
>
> It seems like it was a mistake to include support for hugetlb memfds in udmabuf.
IIUC, it was added with commit 16c243e99d33 udmabuf: Add support for mapping
hugepages (v4). Looks like it was never sent to linux-mm? That is unfortunate
as hugetlb vmemmap freeing went in at about the same time. And, as you have
noted udmabuf will not work if hugetlb vmemmap freeing is enabled.
Sigh!
Trying to think of a way forward.
--
Mike Kravetz
>
> [1]: https://lore.kernel.org/linux-mm/20230306230004.1387007-2-jthoughton@google.com/
>
> - James
next prev parent reply other threads:[~2023-05-12 23:30 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-12 7:20 Junxiao Chang
2023-05-12 21:03 ` Andrew Morton
2023-05-15 0:08 ` Chang, Junxiao
2023-05-12 21:26 ` James Houghton
2023-05-12 23:29 ` Mike Kravetz [this message]
2023-05-15 0:44 ` Chang, Junxiao
2023-05-15 17:04 ` Mike Kravetz
2023-05-16 22:34 ` Mike Kravetz
2023-06-07 19:03 ` Andrew Morton
2023-06-07 20:53 ` Mike Kravetz
2023-06-07 21:00 ` Andrew Morton
2023-06-07 21:16 ` Mike Kravetz
2023-06-08 7:59 ` Greg Kroah-Hartman
2023-06-07 19:27 ` David Hildenbrand
2023-06-19 12:27 ` Gerd Hoffmann
2023-06-20 6:23 ` Kasireddy, Vivek
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