From: John Hubbard <jhubbard@nvidia.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>,
"Darrick J . Wong" <djwong@kernel.org>,
Trond Myklebust <trond.myklebust@hammerspace.com>,
Anna Schumaker <anna@kernel.org>, Jan Kara <jack@suse.cz>,
David Hildenbrand <david@redhat.com>,
Logan Gunthorpe <logang@deltatee.com>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-xfs@vger.kernel.org, linux-nfs@vger.kernel.org,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 7/7] fuse: convert direct IO paths to use FOLL_PIN
Date: Wed, 31 Aug 2022 18:33:30 -0700 [thread overview]
Message-ID: <06d2caf4-eff1-f537-aa33-c4f0220a9f80@nvidia.com> (raw)
In-Reply-To: <CAJfpegvdTqdk9rs-yaEp1aqav4=t9qSpQri7gW8zzb+t7+_88A@mail.gmail.com>
On 8/31/22 03:37, Miklos Szeredi wrote:
Hi Miklos,
Thanks for looking at this, I'll accept all of these suggestions.
> On Wed, 31 Aug 2022 at 06:19, John Hubbard <jhubbard@nvidia.com> wrote:
>>
>> Convert the fuse filesystem to use pin_user_pages_fast() and
>> unpin_user_page(), instead of get_user_pages_fast() and put_page().
>>
>> The user of pin_user_pages_fast() depends upon:
>>
>> 1) CONFIG_BLK_USE_PIN_USER_PAGES_FOR_DIO, and
>>
>> 2) User-space-backed pages or ITER_BVEC pages.
>>
>> Signed-off-by: John Hubbard <jhubbard@nvidia.com>
>> ---
>> fs/fuse/dev.c | 11 +++++++++--
>> fs/fuse/file.c | 32 +++++++++++++++++++++-----------
>> fs/fuse/fuse_i.h | 1 +
>> 3 files changed, 31 insertions(+), 13 deletions(-)
>>
>> diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
>> index 51897427a534..5de98a7a45b1 100644
>> --- a/fs/fuse/dev.c
>> +++ b/fs/fuse/dev.c
>> @@ -675,7 +675,12 @@ static void fuse_copy_finish(struct fuse_copy_state *cs)
>> flush_dcache_page(cs->pg);
>> set_page_dirty_lock(cs->pg);
>> }
>> - put_page(cs->pg);
>> + if (!cs->pipebufs &&
>> + (user_backed_iter(cs->iter) || iov_iter_is_bvec(cs->iter)))
>> + dio_w_unpin_user_page(cs->pg);
>> +
>> + else
>> + put_page(cs->pg);
>
> Why not move the logic into a helper and pass a "bool pinned" argument?
OK, will do.
It's not yet clear from the discussion in the other thread with Jan and Al [1],
if I'll end up keeping this check:
user_backed_iter(cs->iter) || iov_iter_is_bvec(cs->iter)
...but if it stays, then the helper is a good idea.
>
>> }
>> cs->pg = NULL;
>> }
>> @@ -730,7 +735,9 @@ static int fuse_copy_fill(struct fuse_copy_state *cs)
>> }
>> } else {
>> size_t off;
>> - err = iov_iter_get_pages2(cs->iter, &page, PAGE_SIZE, 1, &off);
>> +
>> + err = dio_w_iov_iter_pin_pages(cs->iter, &page, PAGE_SIZE, 1,
>> + &off);
>> if (err < 0)
>> return err;
>> BUG_ON(!err);
>> diff --git a/fs/fuse/file.c b/fs/fuse/file.c
>> index 1a3afd469e3a..01da38928d0b 100644
>> --- a/fs/fuse/file.c
>> +++ b/fs/fuse/file.c
>> @@ -625,14 +625,19 @@ void fuse_read_args_fill(struct fuse_io_args *ia, struct file *file, loff_t pos,
>> }
>>
>> static void fuse_release_user_pages(struct fuse_args_pages *ap,
>> - bool should_dirty)
>> + bool should_dirty, bool is_user_or_bvec)
>> {
>> unsigned int i;
>>
>> - for (i = 0; i < ap->num_pages; i++) {
>> - if (should_dirty)
>> - set_page_dirty_lock(ap->pages[i]);
>> - put_page(ap->pages[i]);
>> + if (is_user_or_bvec) {
>> + dio_w_unpin_user_pages_dirty_lock(ap->pages, ap->num_pages,
>> + should_dirty);
>> + } else {
>> + for (i = 0; i < ap->num_pages; i++) {
>> + if (should_dirty)
>> + set_page_dirty_lock(ap->pages[i]);
>> + put_page(ap->pages[i]);
>> + }
>
> Same here.
Yes. Definitely belongs in a helper function. I was thinking, "don't
go that far, because the code will eventually get deleted anyway", but
you are right. :)
>
>> }
>> }
>>
>> @@ -733,7 +738,7 @@ static void fuse_aio_complete_req(struct fuse_mount *fm, struct fuse_args *args,
>> struct fuse_io_priv *io = ia->io;
>> ssize_t pos = -1;
>>
>> - fuse_release_user_pages(&ia->ap, io->should_dirty);
>> + fuse_release_user_pages(&ia->ap, io->should_dirty, io->is_user_or_bvec);
>>
>> if (err) {
>> /* Nothing */
>> @@ -1414,10 +1419,10 @@ static int fuse_get_user_pages(struct fuse_args_pages *ap, struct iov_iter *ii,
>> while (nbytes < *nbytesp && ap->num_pages < max_pages) {
>> unsigned npages;
>> size_t start;
>> - ret = iov_iter_get_pages2(ii, &ap->pages[ap->num_pages],
>> - *nbytesp - nbytes,
>> - max_pages - ap->num_pages,
>> - &start);
>> + ret = dio_w_iov_iter_pin_pages(ii, &ap->pages[ap->num_pages],
>> + *nbytesp - nbytes,
>> + max_pages - ap->num_pages,
>> + &start);
>> if (ret < 0)
>> break;
>>
>> @@ -1483,6 +1488,10 @@ ssize_t fuse_direct_io(struct fuse_io_priv *io, struct iov_iter *iter,
>> fl_owner_t owner = current->files;
>> size_t nbytes = min(count, nmax);
>>
>> + /* For use in fuse_release_user_pages(): */
>> + io->is_user_or_bvec = user_backed_iter(iter) ||
>> + iov_iter_is_bvec(iter);
>> +
>
> How about io->is_pinned? And a iov_iter_is_pinned() helper?
Agreed, is_pinned is a better name, and the helper (if we end up needing
that logic) also sounds good.
[1] https://lore.kernel.org/r/20220831094349.boln4jjajkdtykx3@quack3
thanks,
--
John Hubbard
NVIDIA
next prev parent reply other threads:[~2022-09-01 1:34 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-31 4:18 [PATCH v2 0/7] convert most filesystems to pin_user_pages_fast() John Hubbard
2022-08-31 4:18 ` [PATCH v2 1/7] mm: change release_pages() to use unsigned long for npages John Hubbard
2022-08-31 4:18 ` [PATCH v2 2/7] mm/gup: introduce pin_user_page() John Hubbard
2022-09-06 6:37 ` Christoph Hellwig
2022-09-06 7:12 ` John Hubbard
2022-08-31 4:18 ` [PATCH v2 3/7] block: add dio_w_*() wrappers for pin, unpin user pages John Hubbard
2022-08-31 4:18 ` [PATCH v2 4/7] iov_iter: new iov_iter_pin_pages*() routines John Hubbard
2022-09-01 0:42 ` Al Viro
2022-09-01 1:48 ` John Hubbard
2022-09-06 6:47 ` Christoph Hellwig
2022-09-06 7:44 ` John Hubbard
2022-09-06 7:48 ` Christoph Hellwig
2022-09-06 7:58 ` John Hubbard
2022-09-07 8:50 ` Christoph Hellwig
2022-09-06 10:21 ` Jan Kara
2022-09-07 8:45 ` Christoph Hellwig
2022-09-14 3:51 ` Al Viro
2022-09-14 14:52 ` Jan Kara
2022-09-14 16:42 ` Al Viro
2022-09-15 8:16 ` Jan Kara
2022-09-16 1:55 ` Al Viro
2022-09-20 5:02 ` Al Viro
2022-09-22 14:36 ` Christoph Hellwig
2022-09-22 14:43 ` David Hildenbrand
2022-09-22 14:45 ` Christoph Hellwig
2022-09-22 2:22 ` Al Viro
2022-09-22 6:09 ` John Hubbard
2022-09-22 11:29 ` Jan Kara
2022-09-23 3:19 ` Al Viro
2022-09-23 4:05 ` John Hubbard
2022-09-23 8:39 ` Christoph Hellwig
2022-09-23 12:22 ` Jan Kara
2022-09-23 4:34 ` John Hubbard
2022-09-22 14:38 ` Christoph Hellwig
2022-09-23 4:22 ` Al Viro
2022-09-23 8:44 ` Christoph Hellwig
2022-09-23 16:13 ` Al Viro
2022-09-26 15:53 ` Christoph Hellwig
2022-09-26 19:55 ` Al Viro
2022-09-22 14:31 ` Christoph Hellwig
2022-09-22 14:36 ` Al Viro
2022-08-31 4:18 ` [PATCH v2 5/7] block, bio, fs: convert most filesystems to pin_user_pages_fast() John Hubbard
2022-09-06 6:48 ` Christoph Hellwig
2022-09-06 7:15 ` John Hubbard
2022-08-31 4:18 ` [PATCH v2 6/7] NFS: direct-io: convert to FOLL_PIN pages John Hubbard
2022-09-06 6:49 ` Christoph Hellwig
2022-09-06 7:16 ` John Hubbard
2022-08-31 4:18 ` [PATCH v2 7/7] fuse: convert direct IO paths to use FOLL_PIN John Hubbard
2022-08-31 10:37 ` Miklos Szeredi
2022-09-01 1:33 ` John Hubbard [this message]
2022-09-06 6:36 ` [PATCH v2 0/7] convert most filesystems to pin_user_pages_fast() Christoph Hellwig
2022-09-06 7:10 ` John Hubbard
2022-09-06 7:22 ` Christoph Hellwig
2022-09-06 7:37 ` John Hubbard
2022-09-06 7:46 ` Christoph Hellwig
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