It's more about code complexity than performance. down_interruptible() means that you must handle failures - double check that you free all temporary allocations, decrease all reference counts (make the reference counts atomic_t), etc.You have already written the code, so I'd leave it as it is and I'll
blame the book. They probably started from an older version of
fs/pipe.c, which contained _interruptible calls. There are gone now,
this allowed some cleanup.
Well, it's just one line so I would not care, and I'm also open for
suggestions. Does down_interruptible() cost so much more in CPU cycles than
down()?