Commit-ID:  ab522e33f91799661aad47bebb691f241a9f6bb8
Gitweb:     http://git.kernel.org/tip/ab522e33f91799661aad47bebb691f241a9f6bb8
Author:     Dietmar Eggemann <[email protected]>
AuthorDate: Mon, 22 Aug 2016 15:00:41 +0100
Committer:  Ingo Molnar <[email protected]>
CommitDate: Fri, 30 Sep 2016 10:53:19 +0200

sched/fair: Fix fixed point arithmetic width for shares and effective load

Since commit:

  2159197d6677 ("sched/core: Enable increased load resolution on 64-bit 
kernels")

we now have two different fixed point units for load:

- 'shares' in calc_cfs_shares() has 20 bit fixed point unit on 64-bit
  kernels. Therefore use scale_load() on MIN_SHARES.

- 'wl' in effective_load() has 10 bit fixed point unit. Therefore use
  scale_load_down() on tg->shares which has 20 bit fixed point unit on
  64-bit kernels.

Signed-off-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: 
http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
---
 kernel/sched/fair.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8fb4d19..786ef94 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5017,9 +5017,9 @@ static long effective_load(struct task_group *tg, int 
cpu, long wl, long wg)
                 * wl = S * s'_i; see (2)
                 */
                if (W > 0 && w < W)
-                       wl = (w * (long)tg->shares) / W;
+                       wl = (w * (long)scale_load_down(tg->shares)) / W;
                else
-                       wl = tg->shares;
+                       wl = scale_load_down(tg->shares);
 
                /*
                 * Per the above, wl is the new se->load.weight value; since

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