Linux-Fsdevel Archive on lore.kernel.org
help / color / mirror / Atom feed
From: John Hubbard <jhubbard@nvidia.com>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Christoph Hellwig <hch@infradead.org>,
	Ilya Dryomov <idryomov@gmail.com>, Jens Axboe <axboe@kernel.dk>,
	Jeff Layton <jlayton@kernel.org>, <linux-xfs@vger.kernel.org>,
	<linux-fsdevel@vger.kernel.org>, <linux-block@vger.kernel.org>,
	<ceph-devel@vger.kernel.org>, <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/5] bio: Direct IO: convert to pin_user_pages_fast()
Date: Mon, 24 Aug 2020 19:07:02 -0700	[thread overview]
Message-ID: <3072d5a0-43c7-3396-c57f-6af83621b71c@nvidia.com> (raw)
In-Reply-To: <20200825015428.GU1236603@ZenIV.linux.org.uk>

On 8/24/20 6:54 PM, Al Viro wrote:
> On Fri, Aug 21, 2020 at 09:20:54PM -0700, John Hubbard wrote:
> 
>> Direct IO behavior:
>>
>>      ITER_IOVEC:
>>          pin_user_pages_fast();
>>          break;
>>
>>      ITER_KVEC:    // already elevated page refcount, leave alone
>>      ITER_BVEC:    // already elevated page refcount, leave alone
>>      ITER_PIPE:    // just, no :)
> 
> Why?  What's wrong with splice to O_DIRECT file?
> 

Oh! I'll take a look. Is this the fs/splice.c stuff?  I ruled this out early
mainly based on Christoph's comment in [1] ("ITER_PIPE is rejected іn the
direct I/O path"), but if it's supportable then I'll hook it up.

(As you can see, I'm still very much coming up to speed on the various things
that invoke iov_iter_get_pages*().)

[1] https://lore.kernel.org/kvm/20190724061750.GA19397@infradead.org/

thanks,
-- 
John Hubbard
NVIDIA

  parent reply	other threads:[~2020-08-25  2:07 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-22  4:20 John Hubbard
2020-08-22  4:20 ` [PATCH 1/5] iov_iter: introduce iov_iter_pin_user_pages*() routines John Hubbard
2020-08-22  4:20 ` [PATCH 2/5] mm/gup: introduce pin_user_page() John Hubbard
2020-08-22  4:20 ` [PATCH 3/5] bio: convert get_user_pages_fast() --> pin_user_pages_fast() John Hubbard
2020-08-22  4:20 ` [PATCH 4/5] bio: introduce BIO_FOLL_PIN flag John Hubbard
2020-08-23  6:25   ` Christoph Hellwig
2020-08-23  6:57     ` John Hubbard
2020-08-24  7:36       ` John Hubbard
2020-08-24  9:20     ` Jens Axboe
2020-08-24 14:42       ` Christoph Hellwig
2020-08-22  4:20 ` [PATCH 5/5] fs/ceph: use pipe_get_pages_alloc() for pipe John Hubbard
2020-08-24 10:53   ` Jeff Layton
2020-08-24 17:54     ` John Hubbard
2020-08-24 18:47       ` Jeff Layton
2020-08-24 18:54         ` Matthew Wilcox
2020-08-24 19:02           ` John Hubbard
2020-08-25  1:20           ` [PATCH v2] " John Hubbard
2020-08-25 16:22             ` Jeff Layton
2020-08-25  1:54 ` [PATCH 0/5] bio: Direct IO: convert to pin_user_pages_fast() Al Viro
2020-08-25  2:07   ` Al Viro
2020-08-25  2:13     ` John Hubbard
2020-08-25  2:07   ` John Hubbard [this message]
2020-08-25  2:22     ` Al Viro
2020-08-25  2:27       ` John Hubbard

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=3072d5a0-43c7-3396-c57f-6af83621b71c@nvidia.com \
    --to=jhubbard@nvidia.com \
    --cc=akpm@linux-foundation.org \
    --cc=axboe@kernel.dk \
    --cc=ceph-devel@vger.kernel.org \
    --cc=hch@infradead.org \
    --cc=idryomov@gmail.com \
    --cc=jlayton@kernel.org \
    --cc=linux-block@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-xfs@vger.kernel.org \
    --cc=viro@zeniv.linux.org.uk \
    --subject='Re: [PATCH 0/5] bio: Direct IO: convert to pin_user_pages_fast()' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).