This is off-topic, but maybe one canonical answer will stop others.
	The solid line (around the top and right edges) is a C file,
labelled on the bottom left.  The dashed lines means a function,
labelled on the bottom left.  Light green functions are file-local
(static).  Red functions are exported to modules.  Dark green
functions are called through a pointer.  Other functions are blue.
	Within each function, the circles are loops, the branches are
conditional statements (if, switch, ?:).  The loops approximately
circle the code they loop around.
	So, we can see that do_munmap looks like a loop around a whole
heap of little branchy code.  Indeed, looking at the code in mm/mmap.c,
half the function is a loop.
Hope that helps,
Rusty.
-- Premature optmztion is rt of all evl. --DK - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/