From: Mike Marshall <hubcap@omnibond.com>
To: John Hubbard <jhubbard@nvidia.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Martin Brandenburg <martin@omnibond.com>,
devel@lists.orangefs.org,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH v2] orangefs: convert get_user_pages() --> pin_user_pages()
Date: Mon, 1 Jun 2020 07:13:53 -0400 [thread overview]
Message-ID: <CAOg9mSQYvPcjCOoTj5_zq-62pxe_XCnqxiaiNLefx10M-MSYuw@mail.gmail.com> (raw)
In-Reply-To: <89244e74-f619-e515-083a-3bf2586fa5c3@nvidia.com>
Hi John.
Thanks for the patch, and the testing, and the reference to the
lwn article.
I have also applied your patch to 5.7-rc7 and have run xfstests.
I applied your patch to the orangefs for-next tree.
-Mike
On Sat, May 30, 2020 at 3:39 AM John Hubbard <jhubbard@nvidia.com> wrote:
>
> On 2020-05-22 20:59, John Hubbard wrote:
> > This code was using get_user_pages*(), in a "Case 1" scenario
> > (Direct IO), using the categorization from [1]. That means that it's
> > time to convert the get_user_pages*() + put_page() calls to
> > pin_user_pages*() + unpin_user_pages() calls.
> >
> > There is some helpful background in [2]: basically, this is a small
> > part of fixing a long-standing disconnect between pinning pages, and
> > file systems' use of those pages.
> >
> > [1] Documentation/core-api/pin_user_pages.rst
> >
> > [2] "Explicit pinning of user-space pages":
> > https://lwn.net/Articles/807108/
> >
> > Cc: Mike Marshall <hubcap@omnibond.com>
> > Cc: Martin Brandenburg <martin@omnibond.com>
> > Cc: devel@lists.orangefs.org
> > Cc: linux-fsdevel@vger.kernel.org
> > Signed-off-by: John Hubbard <jhubbard@nvidia.com>
> > ---
> >
> > Hi,
> >
> > Note that I have only compile-tested this patch, although that does
> > also include cross-compiling for a few other arches.
>
> An update on the run-time testing: Just now, I got basic orangefs tests
> running in xfstests, with this patch applied, and it all looks normal.
>
> thanks,
> --
> John Hubbard
> NVIDIA
>
> >
> > Changes since v1 [3]: correct the commit description, so that
> > it refers to "Case 1" instead of "Case 2".
> >
> >
> > [3] https://lore.kernel.org/r/20200518060139.2828423-1-jhubbard@nvidia.com
> >
> > thanks,
> > John Hubbard
> > NVIDIA
> >
> > fs/orangefs/orangefs-bufmap.c | 9 +++------
> > 1 file changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/fs/orangefs/orangefs-bufmap.c b/fs/orangefs/orangefs-bufmap.c
> > index 2bb916d68576..538e839590ef 100644
> > --- a/fs/orangefs/orangefs-bufmap.c
> > +++ b/fs/orangefs/orangefs-bufmap.c
> > @@ -168,10 +168,7 @@ static DEFINE_SPINLOCK(orangefs_bufmap_lock);
> > static void
> > orangefs_bufmap_unmap(struct orangefs_bufmap *bufmap)
> > {
> > - int i;
> > -
> > - for (i = 0; i < bufmap->page_count; i++)
> > - put_page(bufmap->page_array[i]);
> > + unpin_user_pages(bufmap->page_array, bufmap->page_count);
> > }
> >
> > static void
> > @@ -268,7 +265,7 @@ orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
> > int offset = 0, ret, i;
> >
> > /* map the pages */
> > - ret = get_user_pages_fast((unsigned long)user_desc->ptr,
> > + ret = pin_user_pages_fast((unsigned long)user_desc->ptr,
> > bufmap->page_count, FOLL_WRITE, bufmap->page_array);
> >
> > if (ret < 0)
> > @@ -280,7 +277,7 @@ orangefs_bufmap_map(struct orangefs_bufmap *bufmap,
> >
> > for (i = 0; i < ret; i++) {
> > SetPageError(bufmap->page_array[i]);
> > - put_page(bufmap->page_array[i]);
> > + unpin_user_page(bufmap->page_array[i]);
> > }
> > return -ENOMEM;
> > }
> >
>
prev parent reply other threads:[~2020-06-01 11:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-23 3:59 [PATCH v2] orangefs: convert get_user_pages() --> pin_user_pages() John Hubbard
2020-05-30 7:39 ` John Hubbard
2020-06-01 11:13 ` Mike Marshall [this message]
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