Messages in this thread | | | Date | Sun, 10 Oct 1999 16:38:32 -0400 | From | Jeff Garzik <> | Subject | Re: More on bigger kdev_t |
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Alan Cox wrote: > > > > The kernel makes quite heavy use of kdev_t. That means carrying around > > > expensive to handle multi-register objects is right out > > > > ... so that would mean we should use a pointer to the structure > > instead of directly passing the structure. > > That means a pointer dereference and a potential cache miss every time.
So what is the best solution?
If it is a pointer, you can store other device info besides major/minor in the struct, eliminating the need to scan arrays of such information indexed by major/minor.
IMHO, if kdev_t is unsigned long, you get larger major/minors on 32-bit and 64-bit platforms, while still only carrying around a "machine int".
Jeff
-- Custom driver development | Never worry about theory as long Open source programming | as the machinery does what it's | supposed to do. -- R. A. Heinlein
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