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From: Miklos Szeredi <miklos@szeredi.hu>
To: a.p.zijlstra@chello.nl
Cc: jdike@addtoit.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: per-bdi-throttling: synchronous writepage doesn't work correctly
Date: Thu, 01 Nov 2007 18:00:47 +0100	[thread overview]
Message-ID: <E1IndPT-00047e-00@dorka.pomaz.szeredi.hu> (raw)
In-Reply-To: <1193935886.27652.313.camel@twins> (message from Peter Zijlstra on Thu, 01 Nov 2007 17:51:26 +0100)

> > Hi,
> > 
> > It looks like bdi_thresh will always be zero if filesystem does
> > synchronous writepage, resulting in very poor write performance.
> > 
> > Hostfs (UML) is one such example, but there might be others.
> > 
> > The only solution I can think of is to add a set_page_writeback();
> > end_page_writeback() pair (or some reduced variant, that only does
> > the proportions magic).  But that means auditing quite a few
> > filesystems...
> 
> Ouch...
> 
> I take it there is no other function that is shared between all these
> writeout paths which we could stick a bdi_writeout_inc(bdi) in?

No, and you can't detect it from the callers either I think.

Miklos

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  reply	other threads:[~2007-11-01 17:00 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-11-01 16:49 Miklos Szeredi
2007-11-01 16:51 ` Peter Zijlstra
2007-11-01 17:00   ` Miklos Szeredi [this message]
2007-11-01 17:09     ` Peter Zijlstra
2007-11-01 17:16       ` Peter Zijlstra
2007-11-01 18:35         ` Peter Zijlstra
2007-11-01 19:19           ` Miklos Szeredi
2007-11-01 19:55             ` Peter Zijlstra
2007-11-01 17:28       ` Miklos Szeredi
2007-11-01 17:39         ` Peter Zijlstra

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