Subject: Re: CVS commit: syssrc/sys/arch/arm/arm32
To: Chuck Silvers <chuq@chuq.com>
From: Richard Earnshaw <rearnsha@arm.com>
List: port-arm32
Date: 07/10/2001 10:01:17
chuq@chuq.com said:
> (2) when we're reading the page from memory to write it to backing
> store.
> this use also involves careful ordering of operations in
> pmap_clear_modify(), so that any writes to the page via other
> mappings which could end up in different cache lines will also
> result in the page being marked modified again, so that we'll
> be forced to write the page to backing store again at some point
> in the future.
Hmm, I'm not sure if this is relevant, but the arm32 pmap_protect()
implementation does not flush the cache when a page is marked read-only.
I discovered this to my cost when trying to optimize pmap_copy_page to
minimize cache flushes.
R.