public inbox for [email protected]
 help / color / mirror / Atom feed
From: Keith Busch <[email protected]>
To: Christoph Hellwig <[email protected]>
Cc: Bart Van Assche <[email protected]>,
	Keith Busch <[email protected]>,
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected], [email protected],
	[email protected]
Subject: Re: [PATCHv10 4/9] block: allow ability to limit partition write hints
Date: Wed, 30 Oct 2024 14:11:44 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

On Wed, Oct 30, 2024 at 05:46:58AM +0100, Christoph Hellwig wrote:
> On Tue, Oct 29, 2024 at 10:25:11AM -0700, Bart Van Assche wrote:
> >> +}
> >
> > bitmap_copy() is not atomic. Shouldn't the bitmap_copy() call be
> > serialized against the code that tests bits in bdev->write_hint_mask?
> 
> It needs something.  I actually pointed that out last round, but forgot
> about it again this time :)

I disagree. Whether we serialize it or not, writes in flight will either
think it can write or it won't. There's no point adding any overhead to
the IO path for this as you can't stop ending up with inflight writes
using the tag you're trying to turn off.

This is the same as the "ro" attribute. If you're changing it with
BLKROSET ioctl with writes in flight, some of those writes may get past
blkdev_write_iter's read-only check, others may not. No serialization
done there, and this pretty much the same thing.

  reply	other threads:[~2024-10-30 20:11 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-29 15:19 [PATCHv10 0/9] write hints with nvme fdp, scsi streams Keith Busch
2024-10-29 15:19 ` [PATCHv10 1/9] block: use generic u16 for write hints Keith Busch
2024-10-29 17:21   ` Bart Van Assche
2024-10-29 15:19 ` [PATCHv10 2/9] block: introduce max_write_hints queue limit Keith Busch
2024-10-29 15:19 ` [PATCHv10 3/9] statx: add write hint information Keith Busch
2024-10-29 15:19 ` [PATCHv10 4/9] block: allow ability to limit partition write hints Keith Busch
2024-10-29 15:23   ` Christoph Hellwig
2024-10-29 17:25   ` Bart Van Assche
2024-10-30  4:46     ` Christoph Hellwig
2024-10-30 20:11       ` Keith Busch [this message]
2024-10-30 20:26         ` Bart Van Assche
2024-10-30 20:37           ` Keith Busch
2024-10-30 21:15             ` Bart Van Assche
2024-10-29 15:19 ` [PATCHv10 5/9] block, fs: add write hint to kiocb Keith Busch
2024-10-29 15:19 ` [PATCHv10 6/9] io_uring: enable per-io hinting capability Keith Busch
2024-10-29 15:19 ` [PATCHv10 7/9] block: export placement hint feature Keith Busch
2024-10-29 15:19 ` [PATCHv10 8/9] nvme: enable FDP support Keith Busch
2024-10-30  0:24   ` Chaitanya Kulkarni
2024-10-29 15:19 ` [PATCHv10 9/9] scsi: set permanent stream count in block limits Keith Busch
2024-10-29 15:26   ` Christoph Hellwig
2024-10-29 15:34     ` Keith Busch
2024-10-29 15:37       ` Christoph Hellwig
2024-10-29 15:38         ` Keith Busch
2024-10-29 15:53           ` Christoph Hellwig
2024-10-29 16:22             ` Keith Busch
2024-10-30  4:55               ` Christoph Hellwig
2024-10-30 15:41                 ` Keith Busch
2024-10-30 15:45                   ` Christoph Hellwig
2024-10-30 15:48                     ` Keith Busch
2024-10-30 15:50                       ` Christoph Hellwig
2024-10-30 16:42                         ` Keith Busch
2024-10-30 16:57                           ` Christoph Hellwig
2024-10-30 17:05                             ` Keith Busch
2024-10-30 17:15                               ` Christoph Hellwig
2024-10-30 17:23                             ` Keith Busch
2024-10-30 22:32                             ` Keith Busch
2024-10-30 16:59                 ` Bart Van Assche
2024-10-30 17:14                   ` Christoph Hellwig
2024-10-30 17:44                     ` Bart Van Assche
2024-10-29 17:18     ` Bart Van Assche
2024-10-30  5:42       ` Christoph Hellwig
2024-10-29 15:24 ` [PATCHv10 0/9] write hints with nvme fdp, scsi streams Christoph Hellwig

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 \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /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
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox