[PATCH v4 2/9] perf, x86: use context switch callback to flush LBR stack

Previous commit introduces context switch callback, its function overlaps with the flush branch stack callback. So we can use the context switch callback to flush LBR stack. This patch adds code that uses the flush branch callback to flush the LBR stack when task is being scheduled in. The

[PATCH v4 2/9] perf, x86: use context switch callback to flush LBR stack

Previous commit introduces context switch callback, its function overlaps with the flush branch stack callback. So we can use the context switch callback to flush LBR stack. This patch adds code that uses the flush branch callback to flush the LBR stack when task is being scheduled in. The