From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <199908292028.WAA00305@piglet.cpu.lu> Date: Sun, 29 Aug 1999 22:28:38 +0200 (CEST) From: Michel Lanners Reply-To: mlan@cpu.lu Subject: Re: Zero Pages / Cache Coherency To: apc@agelectronics.co.uk cc: linuxppc-dev@lists.linuxppc.org In-Reply-To: <37C65FF0.A5FBD535@agelectronics.co.uk> MIME-Version: 1.0 Content-Type: TEXT/plain; CHARSET=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: On 27 Aug, this message from Adrian Cox echoed through cyberspace: > > I'm currently trying out the pre-zeroing of pages in the idle task, and > I'm a little worried about its effect on cache-coherency. I can't prove > to > my satisfaction that none of the pages being cleared by zero_paged() is > in the cache, and I'm not sure that turning off caching in the PTE will > have any effect on cache lines already allocated in L1 or L2. Cort Dougan had a paper about memory management in Linux on the PowerPC online at NMT, but at this time the link is broken (http://www.cs.nmt.edu/~cort/papers/linuxppc-mm/). If I remeber right, he also spoke about zeroing pegaes in the idle task. Cort, are you among us? What's up with your personal pages? > Obviously, any incoherency would be extremely rare, but ensuring that > the page is invalidated from the caches before it is zeroed has the > added bonus of removing the need for a flush_page_to_ram() in my > modified anonymous memory allocator. I can't remeber whether Cort also treated this subject. Michel ------------------------------------------------------------------------- Michel Lanners | " Read Philosophy. Study Art. 23, Rue Paul Henkes | Ask Questions. Make Mistakes. L-1710 Luxembourg | email mlan@cpu.lu | http://www.cpu.lu/~mlan | Learn Always. " [[ This message was sent via the linuxppc-dev mailing list. Replies are ]] [[ not forced back to the list, so be sure to Cc linuxppc-dev if your ]] [[ reply is of general interest. Please check http://lists.linuxppc.org/ ]] [[ and http://www.linuxppc.org/ for useful information before posting. ]]