On Thu, Aug 08, 2013 at 12:43:26AM -0700, Kent Overstreet wrote: > I seem to recall from looking at the logs that you just removed them > because all the old users could be and were converted to something > saner, for what they were doing (using them as completions, I want to > say?)
We explicitly converted them away so that we could kill it. This was a joint project with Thomas. > Bcache isn't using the rw sem as a completion though, it really is a > read/write lock that protects a specific data structure, and where > we're taking a read lock for the duration of write IOs - and since bios > are asynchronous, that's why we need the non_owner() bit. Part of this commit was to make the rw_semaphore behaviour similar to plain mutex, that is making sure there is exactly one owner and not different processes locking/unlocking it. This is useful for PI (that's why the rt folks care), lock debugging and kinds of other use cases. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
