From: Christoph Hellwig <hch@lst.de>
To: Jan Kara <jack@suse.cz>
Cc: John Hubbard <jhubbard@nvidia.com>,
Jason Gunthorpe <jgg@nvidia.com>,
linux-kernel@vger.kernel.org,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@lst.de>, Hugh Dickins <hughd@google.com>,
Jann Horn <jannh@google.com>,
Kirill Shutemov <kirill@shutemov.name>,
Kirill Tkhai <ktkhai@virtuozzo.com>,
Linux-MM <linux-mm@kvack.org>, Michal Hocko <mhocko@suse.com>,
Oleg Nesterov <oleg@redhat.com>, Peter Xu <peterx@redhat.com>
Subject: Re: [PATCH 1/2] mm: reorganize internal_get_user_pages_fast()
Date: Tue, 27 Oct 2020 10:55:45 +0100 [thread overview]
Message-ID: <20201027095545.GA30382@lst.de> (raw)
In-Reply-To: <20201027093301.GA16090@quack2.suse.cz>
On Tue, Oct 27, 2020 at 10:33:01AM +0100, Jan Kara wrote:
> Actually there are callers that care about partial success. See e.g.
> iov_iter_get_pages() usage in fs/direct_io.c:dio_refill_pages() or
> bio_iov_iter_get_pages(). These places handle partial success just fine and
> not allowing partial success from GUP could regress things...
But most users do indeed not care. Maybe an explicit FOLL_PARTIAL to
opt into partial handling could clean up a lot of the mess. Maybe just
for pin_user_pages for now.
next prev parent reply other threads:[~2020-10-27 9:55 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-24 0:19 [PATCH 0/2] Add a 'seqcount' between gup_fast and copy_page_range Jason Gunthorpe
2020-10-24 0:19 ` [PATCH 1/2] mm: reorganize internal_get_user_pages_fast() Jason Gunthorpe
2020-10-24 4:44 ` John Hubbard
2020-10-26 23:59 ` Jason Gunthorpe
2020-10-27 9:33 ` Jan Kara
2020-10-27 9:55 ` Christoph Hellwig [this message]
2020-10-28 6:00 ` John Hubbard
2020-10-27 13:15 ` Jason Gunthorpe
2020-10-28 6:00 ` John Hubbard
2020-10-28 6:05 ` John Hubbard
2020-10-24 0:19 ` [PATCH 2/2] mm: prevent gup_fast from racing with COW during fork Jason Gunthorpe
2020-10-24 5:19 ` John Hubbard
2020-10-24 5:31 ` John Hubbard
2020-10-26 23:49 ` Jason Gunthorpe
2020-10-27 0:14 ` Linus Torvalds
2020-10-27 11:32 ` Jason Gunthorpe
2020-10-27 0:35 ` John Hubbard
2020-10-27 7:32 ` John Hubbard
2020-11-02 3:25 ` [mm] e498078ae9: will-it-scale.per_thread_ops -1.4% regression kernel test robot
2020-10-24 5:14 ` [PATCH 0/2] Add a 'seqcount' between gup_fast and copy_page_range John Hubbard
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