Documentation/kernel-parameters.txt: update 'isolcpus' kernel option

cpuset can be used to move a process onto or off an isolated CPU.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/kernel-parameters.txt

@@ -995,13 +995,15 @@ and is between 256 and 4096 characters. It is defined in the file
 			Format:
 			<cpu number>,...,<cpu number>
 			or
-			<cpu number>-<cpu number>  (must be a positive range in ascending order)
+			<cpu number>-<cpu number>
+			(must be a positive range in ascending order)
 			or a mixture
 			<cpu number>,...,<cpu number>-<cpu number>
+
 			This option can be used to specify one or more CPUs
 			to isolate from the general SMP balancing and scheduling
-			algorithms. The only way to move a process onto or off
-			an "isolated" CPU is via the CPU affinity syscalls.
+			algorithms. You can move a process onto or off an
+			"isolated" CPU via the CPU affinity syscalls or cpuset.
 			<cpu number> begins at 0 and the maximum value is
 			"number of CPUs in system - 1".