[tip:sched/core] sched/deadline: Fix rt runtime corruption when dl fails its global constraints

From: tip-bot for Wanpeng Li
Date: Fri Mar 27 2015 - 07:44:50 EST


Commit-ID: a1963b81deec54c113e770b0020e5f1c3188a087
Gitweb: http://git.kernel.org/tip/a1963b81deec54c113e770b0020e5f1c3188a087
Author: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
AuthorDate: Tue, 17 Mar 2015 19:15:31 +0800
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 27 Mar 2015 09:36:15 +0100

sched/deadline: Fix rt runtime corruption when dl fails its global constraints

One version of sched_rt_global_constaints() (the !rt-cgroup one)
changes state, therefore if we fail the later sched_dl_global_constraints()
call the state is left in an inconsistent state.

Fix this by changing the order of the calls.

Signed-off-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxxxxxx>
[ Improved the changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Juri Lelli <juri.lelli@xxxxxxx>
Link: http://lkml.kernel.org/r/1426590931-4639-2-git-send-email-wanpeng.li@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/core.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 043e2a1..4b3b688 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7804,7 +7804,7 @@ static int sched_rt_global_constraints(void)
}
#endif /* CONFIG_RT_GROUP_SCHED */

-static int sched_dl_global_constraints(void)
+static int sched_dl_global_validate(void)
{
u64 runtime = global_rt_runtime();
u64 period = global_rt_period();
@@ -7905,11 +7905,11 @@ int sched_rt_handler(struct ctl_table *table, int write,
if (ret)
goto undo;

- ret = sched_rt_global_constraints();
+ ret = sched_dl_global_validate();
if (ret)
goto undo;

- ret = sched_dl_global_constraints();
+ ret = sched_rt_global_constraints();
if (ret)
goto undo;

--
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