Messages in this thread | | | Date | Tue, 28 Apr 2015 15:35:26 +0000 (UTC) | From | Mathieu Desnoyers <> | Subject | Using pmem from a driver exposing a memory mapping (mmap) to userspace |
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Hi!
I'm currently adaping lttng-modules to use DAX and pmem. It will allow LTTng buffers to be recovered after a kernel crash. I've moved pretty much all struct page pointers to page frame numbers, as I remember being told that pmem does not have struct page.
Now I'm looking into adapting my mmap and page fault handler implementation (based on struct page) to a page-frame number based implementation when the ring buffer is backed by persistent memory, which will probably not require any page fault handler at all when based by pmem+dax memory.
My current work is in this branch: https://github.com/compudj/lttng-modules-dev/tree/persistent-memory-buffers (see last commits)
LTTng-modules supports both mmap() and splice(), but I plan to only provide mmap() support for persistent memory, since splice() really requires struct page.
Are there existing driver mmap implementations doing similar things, or do you have recommendations on how to implement this ?
Thanks,
Mathieu
-- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com
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