From: Christoph Hellwig <hch@infradead.org>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, linux-stable@vger.kernel.org,
Vivek Kasireddy <vivek.kasireddy@intel.com>,
David Hildenbrand <david@redhat.com>,
Dave Airlie <airlied@redhat.com>,
Gerd Hoffmann <kraxel@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Christoph Hellwig <hch@infradead.org>,
Jason Gunthorpe <jgg@nvidia.com>, Peter Xu <peterx@redhat.com>,
Arnd Bergmann <arnd@arndb.de>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Dongwon Kim <dongwon.kim@intel.com>,
Hugh Dickins <hughd@google.com>,
Junxiao Chang <junxiao.chang@intel.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Oscar Salvador <osalvador@suse.de>
Subject: Re: [PATCH] mm/gup: restore the ability to pin more than 2GB at a time
Date: Tue, 29 Oct 2024 21:21:40 -0700 [thread overview]
Message-ID: <ZyG0VKUpFttPF30f@infradead.org> (raw)
In-Reply-To: <20241030030116.670307-1-jhubbard@nvidia.com>
On Tue, Oct 29, 2024 at 08:01:16PM -0700, John Hubbard wrote:
> A user-visible consequence has now appeared: user space can no longer
> pin more than 2GB of memory anymore on x86_64. That's because, on a 4KB
> PAGE_SIZE system, when user space tries to (indirectly, via a device
> driver that calls pin_user_pages()) pin 2GB, this requires an allocation
> of a folio pointers array of MAX_PAGE_ORDER size, which is the limit for
> kmalloc().
Do you have a report whee someone tries to pin that much memor in a
single call? What driver is this? Because it seems like a not very
smart thing to do.
next prev parent reply other threads:[~2024-10-30 4:21 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-30 3:01 [PATCH] mm/gup: restore the ability to pin more than 2GB at a time John Hubbard
2024-10-30 3:02 ` kernel test robot
2024-10-30 3:10 ` John Hubbard
2024-10-30 4:21 ` Christoph Hellwig [this message]
2024-10-30 4:30 ` John Hubbard
2024-10-30 4:33 ` Christoph Hellwig
2024-10-30 4:39 ` John Hubbard
2024-10-30 4:42 ` Christoph Hellwig
2024-10-30 4:44 ` John Hubbard
2024-10-30 6:18 ` Alistair Popple
2024-10-30 6:50 ` John Hubbard
2024-10-30 8:34 ` David Hildenbrand
2024-10-30 9:01 ` David Hildenbrand
2024-10-30 18:34 ` John Hubbard
2024-10-31 0:02 ` Jason Gunthorpe
2024-10-31 0:17 ` John Hubbard
2024-10-31 0:25 ` Jason Gunthorpe
2024-10-31 0:47 ` John Hubbard
2024-10-30 12:04 ` Jason Gunthorpe
2024-10-30 17:25 ` John Hubbard
2024-10-30 11:59 ` Jason Gunthorpe
2024-10-30 11:03 ` Vlastimil Babka
2024-10-30 17:29 ` John Hubbard
2024-10-30 17:42 ` Vlastimil Babka
2024-10-30 17:49 ` John Hubbard
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