Messages in this thread |  | | From | Goswin von Brederlow <> | Subject | Re: [fuse-devel] [PATCH] FUSE/CUSE: implement direct mmap support | Date | Wed, 10 Feb 2010 09:24:13 +0100 |
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Tejun Heo <tj@kernel.org> writes:
> Implement FUSE direct mmap support. The server can redirect client > mmap requests to any SHMLBA aligned offset in the custom address space > attached to the fuse channel. The address space is managed by the > server using mmap/munmap(2). The SHMLBA alignment requirement is > necessary to avoid cache aliasing issues on archs with virtually > indexed caches as FUSE direct mmaps are basically shared memory > between clients and the server. > > The direct mmap address space is backed by pinned kernel pages which > are allocated on the first fault either from a client or the server. > If used carelessly, this can easily waste and drain memory. > Currently, a server must have CAP_SYS_ADMIN to manage dmmap regions by > mmapping and munmapping the channel fd.
Does that mean that for example in unionfs-fuse when a user wants to mmap a file I can just mmap the actual underlying file from the real filesystem and any read/write access would then shortcut fuse and go directly to the real file?
MfG Goswin
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