d503b971f4
The spl_rwsem_is_locked() compatibility function has been observed to be a hot spot. The root cause of this is that we must check the rwsem activity under the rwsem->wait_lock to avoid a race. When the lock is busy significant contention can occur. The upstream kernel fix for this race had the insight that by using spin_trylock_irqsave() this contention could be avoided. When the lock is contended it's reasonable to return that it is locked. This change updates the SPLs implemention to be like the upstream kernel. Since the kernel code has been in use for years now this a low risk change. Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
The Solaris Porting Layer (SPL) is a Linux kernel module which provides many of the Solaris kernel APIs. This shim layer makes it possible to run Solaris kernel code in the Linux kernel with relatively minimal modification. This can be particularly useful when you want to track upstream Solaris development closely and don’t want the overhead of maintaining a large patch which converts Solaris primitives to Linux primitives.
To build packages for your distribution:
$ ./configure
$ make pkg
Full documentation for building, configuring, and using the SPL can be found at: http://zfsonlinux.org