arch/powerpc/lib/Kconfig

config CACHE_FLUSH_WATCHDOG_THRESHOLD
	int "Bytes to flush between WATCHDOG_RESET calls"
	default 0
	help
	  The flush_cache() function periodically, and by default for
	  every cache line, calls WATCHDOG_RESET(). When flushing a
	  large area, that may add a significant amount of
	  overhead. This option allows you to set a threshold for how
	  many bytes to flush between each WATCHDOG_RESET call.