Re: [RFC PATCH 08/11] sched: Remove SD_WAKE_AFFINE flag and replace it with SD_BALANCE_WAKE

From: Mike Galbraith
Date: Thu Jun 23 2016 - 10:06:15 EST


On Thu, 2016-06-23 at 14:04 +0100, Matt Fleming wrote:

> I'm curious - doesn't this break userspace ABI? These flags are
> exported via procfs, so I would have assumed removing or changing the
> value of any of these constants would be forbidden.

Nope, if those change, you get to fix up your toys. Hopping in the way
way back machine...

@ -460,10 +460,11 @@ enum idle_type
#define SD_LOAD_BALANCE 1 /* Do load balancing on this domain. */
#define SD_BALANCE_NEWIDLE 2 /* Balance when about to become idle */
#define SD_BALANCE_EXEC 4 /* Balance on exec */
-#define SD_WAKE_IDLE 8 /* Wake to idle CPU on task wakeup */
-#define SD_WAKE_AFFINE 16 /* Wake task to waking CPU */
-#define SD_WAKE_BALANCE 32 /* Perform balancing at task wakeup */
-#define SD_SHARE_CPUPOWER 64 /* Domain members share cpu power */
+#define SD_BALANCE_FORK 8 /* Balance on fork, clone */
+#define SD_WAKE_IDLE 16 /* Wake to idle CPU on task wakeup */
+#define SD_WAKE_AFFINE 32 /* Wake task to waking CPU */
+#define SD_WAKE_BALANCE 64 /* Perform balancing at task wakeup */
+#define SD_SHARE_CPUPOWER 128 /* Domain members share cpu power */