Messages in this thread | | | Date | Sat, 12 Sep 2009 08:54:02 +0530 | Subject | one question about shared mappings between user space and kernel space. | From | Peter Chacko <> |
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Hi kernel geeks,
Please forgive me if this questions was asked already in the past !!!
I have a question about shared memory mappings between kernel and user process...(.like accessing device memory directly from user space through device mmap interface)...I presume this mechanism use remap_pfn_range() or similar....when such mappings are in place, ( whats the "U/S" flag in the underlying physical page indicating CPL of the page) for such pages ? such page descriptors are stored in normal GDT or considered as global pages ? Any special policies of TLB flush of translations to such pages ?
With a shared memory between user process and kernel using such mechanism, is it equivalent to zero-copy transfer between user space and kernel space? ( I mean any extra overhead in memory access to such pages)
I would appreciate your thoughts on this.
-- Best regards, Peter Chacko
NetDiox computing systems, Network storage & OS training and research. Bangalore, India. www.netdiox.com 080 2664 0708
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