Date: Wed, 13 Sep 2000 03:27:25 +0200 (CEST) From: Marius Bendiksen <mbendiks@eunet.no> To: Christopher Stein <stein@eecs.harvard.edu> Cc: freebsd-fs@FreeBSD.ORG Subject: Re: how mmap buffer writes handled? Message-ID: <Pine.BSF.4.05.10009130324160.85482-100000@login-1.eunet.no> In-Reply-To: <Pine.OSF.4.20.0009121146440.13225-100000@wally>
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> How are these data structures and statistics kept meaningful > under mmapped workloads? Most architectures that have an MMU, such as the x86, have a bit in their page tables or equivalent that will indicate whether a page has been modified since the last time that bit was cleared. This can be sampled and cleared in one go. On architectures lacking an MMU, I think the logical approach would be to use some of the protection facilities or such to force an exception to be raised when accessing the page for write, and updating the statistics based on that. Marius To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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