LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Nick Piggin <npiggin@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Linux Filesystems <linux-fsdevel@vger.kernel.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [rfc][patch 0/3] a faster buffered write deadlock fix?
Date: Fri, 9 Feb 2007 11:32:58 +0100	[thread overview]
Message-ID: <20070209103258.GC14398@wotan.suse.de> (raw)
In-Reply-To: <20070209020954.4951256e.akpm@linux-foundation.org>

On Fri, Feb 09, 2007 at 02:09:54AM -0800, Andrew Morton wrote:
> On Fri, 9 Feb 2007 10:54:05 +0100 Nick Piggin <npiggin@suse.de> wrote:
> 
> > 
> > That's still got a deadlock,
> 
> It does?

Yes, PG_lock vs mm->mmap_sem.

> >  and also it doesn't work if we want to lock
> > the page when performing a minor fault (which I want to fix fault vs
> > invalidate),
> 
> It's hard to discuss this without a description of what you want to fix
> there, and a description of how you plan to fix it.

http://marc.theaimsgroup.com/?l=linux-mm&m=116865911432667&w=2

> > and also assumes nobody's ->nopage locks the page or
> > requires any resources that are held by prepare_write (something not
> > immediately clear to me with the cluster filesystems, at least).
> 
> The nopage handler is filemap_nopage().  Are there any exceptions to that?

OCFS2 and GFS2.

> > But that all becomes legacy path, so do we really care? Supposing fs
> > maintainers like perform_write, then after the main ones have implementations
> > we could switch over to the slow-but-correct prepare_write legacy path.
> > Or we could leave it, or we could use Linus's slightly-less-buggy scheme...
> > by that point I expect I'd be sick of arguing about it ;)
> 
> It's worth "arguing" about.  This is write().  What matters more??

That's the legacy path that uses prepare/commit (ie. supposing that all
major filesystems did get converted to perform_write).

Of course I would still want my correct-but-slow version in that case,
but I just wouldn't care to argue if you still wanted to keep it fast.


  reply	other threads:[~2007-02-09 10:33 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-08 13:07 Nick Piggin
2007-02-08 13:07 ` [patch 1/3] fs: add an iovec iterator Nick Piggin
2007-02-08 19:49   ` Christoph Hellwig
2007-02-09  1:46     ` Nick Piggin
2007-02-09  2:03       ` Nate Diller
2007-02-09  3:31         ` Nick Piggin
2007-02-09 17:28           ` Zach Brown
2007-03-09 10:40         ` Christoph Hellwig
2007-02-08 23:04   ` Mark Fasheh
2007-02-08 13:07 ` [patch 2/3] fs: introduce perform_write aop Nick Piggin
2007-03-09 10:39   ` Christoph Hellwig
2007-03-09 12:52     ` Nick Piggin
2007-03-09 22:01       ` Anton Altaparmakov
2007-03-09 23:33     ` Mark Fasheh
2007-03-10  9:25       ` Christoph Hellwig
2007-03-12  2:13         ` Mark Fasheh
2007-03-14 13:30         ` Nick Piggin
2007-03-14 15:17           ` Christoph Hellwig
2007-02-08 13:07 ` [patch 3/3] ext2: use " Nick Piggin
2007-02-08 14:47   ` Dmitriy Monakhov
2007-02-09 19:14   ` Andrew Morton
2007-02-09 19:45     ` Andrew Morton
2007-02-10  1:34       ` Nick Piggin
2007-02-10  1:50         ` Andrew Morton
2007-02-09  0:38 ` [rfc][patch 0/3] a faster buffered write deadlock fix? Mark Fasheh
2007-02-09  2:04   ` Nick Piggin
2007-02-09  8:41 ` Andrew Morton
2007-02-09  9:54   ` Nick Piggin
2007-02-09 10:09     ` Andrew Morton
2007-02-09 10:32       ` Nick Piggin [this message]
2007-02-09 10:52         ` Andrew Morton
2007-02-09 11:31           ` Nick Piggin
2007-02-09 11:46             ` Andrew Morton
2007-02-09 12:11               ` Nick Piggin

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=20070209103258.GC14398@wotan.suse.de \
    --to=npiggin@suse.de \
    --cc=akpm@linux-foundation.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=torvalds@linux-foundation.org \
    --subject='Re: [rfc][patch 0/3] a faster buffered write deadlock fix?' \
    /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).