165f13c33a
The entire goal of performing the slab allocations asynchronously is to be able to detect when a vmalloc() deadlocks. In this case, and only this case, do we want to start allocating emergency objects. The trick here is to minimize false positives because the overhead of tracking emergency objects is far higher than normal slab objects. With that goal in mind the code was reworked to be less sensitive to slow allocations by increasing the wait time. Once a cache is is marked deadlocked all subsequent allocations which can not be satisfied with existing cache objects will immediately allocate new emergency objects. This behavior persists until the asynchronous allocation completes and clears the deadlocked flag. The result of these tweaks is that far fewer emergency objects get created which is important because this minimizes the cost of releasing them latter in kmem_cache_free(). 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
To copy the kernel code inside your kernel source tree for builtin compilation:
$ ./configure --enable-linux-builtin --with-linux=/usr/src/linux-...
$ ./copy-builtin /usr/src/linux-...
Full documentation for building, configuring, and using the SPL can be found at: http://zfsonlinux.org