linux-kernel - Re: [RFC] fuse writable mmap design

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1195156900.22457.32.camel@lappy>
Date:	Thu, 15 Nov 2007 21:01:39 +0100
From:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
To:	Miklos Szeredi <miklos@...redi.hu>
Cc:	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	linux-fsdevel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [RFC] fuse writable mmap design


On Thu, 2007-11-15 at 20:57 +0100, Miklos Szeredi wrote:
> > The next point then, I'd expect your fuse_page_mkwrite() to push
> > writeout of your 32-odd mmap pages instead of poll.
> 
> You're talking about this:
> 
> +	wait_event(fc->writeback_waitq,
> +		   fc->numwrite < FUSE_WRITEBACK_THRESHOLD);
> 
> right?  It's one of the things I need to clean out, there's no point
> in fc->numwrite, which is essentially the same as the BDI_WRITEBACK
> counter.
> 
> OTOH, I'm thinking about adding a per-fs limit (adjustable for
> privileged mounts) of dirty+writeback.
> 
> I'm not sure how hard would it be to add support for this into
> balance_dirty_pages().  So I'm thinking of a parameter in struct
> backing_dev_info that is used to clip the calculated per-bdi threshold
> below this maximum.
> 
> How would that affect the proportions algorithm?  What would happen to
> the unused portion?  Would it adapt to the slowed writeback and
> allocate it to some other writer?

The unused part is gone, I've not yet found a way to re-distribute this
fairly.

[ It's one of my open-problems, I can do a min_ratio per bdi, but not
  yet a max_ratio ]

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/