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Subject: Re: [PATCH]: uClinux (MMU-less) patches against 2.5.28
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Ungerer <gerg@snapgear.com>, linux-kernel@vger.kernel.org,
       David McCullough <davidm@snapgear.com>
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On Fri, 2002-07-26 at 15:03, David Woodhouse wrote:
> Good point -- so if a writer encounters a locked page when it's trying to 
> unmap them all, it needs to still allow other pages to be mapped in while 
> it waits for the original page to become unlocked. That avoids the deadlock 
> -- but leaves us with the potential for livelock, with the writer being 
> starved by too many other things locking down the pages in question.
> 
> I suspect the number of pages getting locked will be sufficiently small 
> that the deadlock does not occur. 

Well for a starter lets try user writing a block to flash which needs an
erase from a block which happens to be not yet paged in and so still on
the flash you are writing to.