linux-kernel - Re: mmap hw behavior

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Message-Id: <20090708.103520.193697491.davem@davemloft.net>
Date:	Wed, 08 Jul 2009 10:35:20 -0700 (PDT)
From:	David Miller <davem@...emloft.net>
To:	michal.simek@...alogix.com
Cc:	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
	mingo@...e.hu, arnd@...db.de, lethal@...ux-sh.org,
	ltp-list@...ts.sourceforge.net
Subject: Re: mmap hw behavior

From: Michal Simek <michal.simek@...alogix.com>
Date: Wed, 08 Jul 2009 19:03:11 +0200

> When I call mmap for that open file with pointer to calloc place
> (first parameter, + length zero) it should be one tlb invalidation
> for calloc and new tlb which connect open file.  We check it and we
> don't have any tlb invalidation that's why I think that kernel do
> different thigs.  Or is it there any copying? Or anything different?

There is no need to tlb flush the calloc area unless that memory area
is actually touched by the user application and thus the page is
faulted in.
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