Date: Fri, 15 Jun 2007 10:13:32 +0300 From: "Ivo Vachkov" <ivo.vachkov@gmail.com> To: "cadastrosonline cadastrosonline" <cadastrosonline@yahoo.com.br> Cc: fbsd arch <freebsd-arch@freebsd.org> Subject: Re: VM Message-ID: <f85d6aa70706150013g56781a02n1d2674080e87395d@mail.gmail.com> In-Reply-To: <497837.24344.qm@web57302.mail.re1.yahoo.com> References: <497837.24344.qm@web57302.mail.re1.yahoo.com>
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On 6/14/07, cadastrosonline cadastrosonline <cadastrosonline@yahoo.com.br> wrote: > "FreeBSD's memory allocation code implements page coloring optimizations,= which means > that the memory allocation code will attempt to locate free pages that ar= e contiguous > from the point of view of the cache. For example, if page 16 of physical = memory is > assigned to page 0 of a process's virtual memory and the cache can hold 4= pages, the page > coloring code will not assign page 20 of physical memory to page 1 of a p= rocess's virtual > memory." > > From fbsd books, I don't understand why it links page 16 of physical memo= ry to page 0 then talks about page 20 of physcal memory to page 1, ok it wi= ll say it will sign to page 21 because of the page coloring, but thats not = what i didnt get. > > If the cache holds 4 pages, why wouldn't the physical page 20 sign to pag= e 4 or 8 instead? Why 1? lol :> i see its signing the VM as 0,1,2,3,4 and t= he physical as 4,8,16,20...could anyone explain that? > > I think, if virtual memory page 0 maps on physical memory page 16, then virtual memory page 1 would map to physical memory page 17 and that's the main idea. Instead, if you map vm page 1 to phys page 20 this will require cache invalidation on access. > > > _________________________________________________________________________= ___________ > Novo Yahoo! Cad=EA? - Experimente uma nova busca. > http://yahoo.com.br/oqueeuganhocomisso > _______________________________________________ > freebsd-arch@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arch > To unsubscribe, send any mail to "freebsd-arch-unsubscribe@freebsd.org" > --=20 "UNIX is basically a simple operating system, but you have to be a genius to understand the simplicity." Dennis Ritchie
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