From: Hugh Dickins <hughd@google.com>
To: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "David Hildenbrand" <david@redhat.com>,
"Hugh Dickins" <hughd@google.com>,
"Patryk Kowalczyk" <patryk@kowalczyk.ws>,
da.gomez@samsung.com, baohua@kernel.org,
wangkefeng.wang@huawei.com, ioworker0@gmail.com,
willy@infradead.org, ryan.roberts@arm.com,
akpm@linux-foundation.org, eero.t.tamminen@intel.com,
"Ville Syrjälä" <ville.syrjala@linux.intel.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: regression - mm: shmem: add large folio support for tmpfs affect GPU performance.
Date: Thu, 24 Jul 2025 21:47:48 -0700 (PDT) [thread overview]
Message-ID: <dab283bf-a9cf-30be-02ed-da0d7c8ffcf0@google.com> (raw)
In-Reply-To: <da2ab844-98c9-4eb2-82ac-01d01bec30f3@linux.alibaba.com>
On Fri, 25 Jul 2025, Baolin Wang wrote:
> >
> > I hope to correct the logic of i915 driver's shmem allocation, by extending
> > the shmem write length in the i915 driver to allocate PMD- sized THPs. IIUC,
> > some sample fix code is as follows (untested). Patryk, could you help test
> > it to see if this resolves your issue? Thanks.
This patch cannot be the right fix. It may be a very sensible workaround
for some in-kernel drivers (I've not looked or tried); but unless I
misunderstand, it does nothing to restore userspace behaviour on a
huge=always tmpfs.
Please reread my comment earlier in the thread, in particular,
Passing a new SIGBUS xfstest does not excuse a regression: strict PAGE_SIZE
SIGBUS behaviour is fine for the newly-featured mTHPs or large folios,
but not for the long-established huge=always.
Thanks,
Hugh
next prev parent reply other threads:[~2025-07-25 4:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CAJCW39JCDX6_S2Ojt1HMmX-h_qAKm2eBRzxX5kOHNJz60Zu=vw@mail.gmail.com>
[not found] ` <d5c6ac93-1af0-4093-afea-94a29a387903@redhat.com>
[not found] ` <63b69425-2fd1-2c77-06d6-e7ea25c92f34@google.com>
[not found] ` <3f204974-26c8-4d5f-b7ae-4052cbfdf4ac@redhat.com>
[not found] ` <a8ac7ec3-4cb3-4dd8-8d02-ede6905f322e@linux.alibaba.com>
2025-07-25 2:38 ` Baolin Wang
2025-07-25 4:47 ` Hugh Dickins [this message]
2025-07-25 6:05 ` Baolin Wang
2025-07-25 8:36 ` Patryk Kowalczyk
2025-07-25 9:17 ` Baolin Wang
2025-07-28 5:35 ` Hugh Dickins
2025-07-28 6:29 ` Baolin Wang
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