linux-ti33x-psp 3.2: update to 3.2.25

Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>
Signed-off-by: Denys Dmytriyenko <denys@ti.com>

1 files changed, 137 insertions, 0 deletions

diff --git a/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.25/0018-sched-nohz-Fix-rq-cpu_load-calculations.patch b/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.25/0018-sched-nohz-Fix-rq-cpu_load-calculations.patch
new file mode 100644
index 00000000..6548d426
--- /dev/null
+++ b/recipes-kernel/linux/linux-ti33x-psp-3.2/3.2.25/0018-sched-nohz-Fix-rq-cpu_load-calculations.patch
@@ -0,0 +1,137 @@
+From af56d9e56ec0729f6aa8c3a51b9bddbdcd8dfcf0 Mon Sep 17 00:00:00 2001
+From: Peter Zijlstra <a.p.zijlstra@chello.nl>
+Date: Fri, 11 May 2012 17:31:26 +0200
+Subject: [PATCH 18/73] sched/nohz: Fix rq->cpu_load[] calculations
+
+commit 556061b00c9f2fd6a5524b6bde823ef12f299ecf upstream.
+
+While investigating why the load-balancer did funny I found that the
+rq->cpu_load[] tables were completely screwy.. a bit more digging
+revealed that the updates that got through were missing ticks followed
+by a catchup of 2 ticks.
+
+The catchup assumes the cpu was idle during that time (since only nohz
+can cause missed ticks and the machine is idle etc..) this means that
+esp. the higher indices were significantly lower than they ought to
+be.
+
+The reason for this is that its not correct to compare against jiffies
+on every jiffy on any other cpu than the cpu that updates jiffies.
+
+This patch cludges around it by only doing the catch-up stuff from
+nohz_idle_balance() and doing the regular stuff unconditionally from
+the tick.
+
+Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
+Cc: pjt@google.com
+Cc: Venkatesh Pallipadi <venki@google.com>
+Link: http://lkml.kernel.org/n/tip-tp4kj18xdd5aj4vvj0qg55s2@git.kernel.org
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+[bwh: Backported to 3.2: adjust filenames and context; keep functions static]
+Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
+---
+ kernel/sched.c      |   53 ++++++++++++++++++++++++++++++++++++++------------
+ kernel/sched_fair.c |    2 +-
+ 2 files changed, 41 insertions(+), 14 deletions(-)
+
+diff --git a/kernel/sched.c b/kernel/sched.c
+index 52ac69b..a409d81 100644
+--- a/kernel/sched.c
++++ b/kernel/sched.c
+@@ -1887,7 +1887,7 @@ static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
+ 
+ static void update_sysctl(void);
+ static int get_update_sysctl_factor(void);
+-static void update_cpu_load(struct rq *this_rq);
++static void update_idle_cpu_load(struct rq *this_rq);
+ 
+ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
+ {
+@@ -3855,22 +3855,13 @@ decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
+  * scheduler tick (TICK_NSEC). With tickless idle this will not be called
+  * every tick. We fix it up based on jiffies.
+  */
+-static void update_cpu_load(struct rq *this_rq)
++static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
++                             unsigned long pending_updates)
+ {
+-       unsigned long this_load = this_rq->load.weight;
+-       unsigned long curr_jiffies = jiffies;
+-       unsigned long pending_updates;
+        int i, scale;
+ 
+        this_rq->nr_load_updates++;
+ 
+-       /* Avoid repeated calls on same jiffy, when moving in and out of idle */
+-       if (curr_jiffies == this_rq->last_load_update_tick)
+-               return;
+-
+-       pending_updates = curr_jiffies - this_rq->last_load_update_tick;
+-       this_rq->last_load_update_tick = curr_jiffies;
+-
+        /* Update our load: */
+        this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */
+        for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
+@@ -3895,9 +3886,45 @@ static void update_cpu_load(struct rq *this_rq)
+        sched_avg_update(this_rq);
+ }
+ 
++/*
++ * Called from nohz_idle_balance() to update the load ratings before doing the
++ * idle balance.
++ */
++static void update_idle_cpu_load(struct rq *this_rq)
++{
++       unsigned long curr_jiffies = jiffies;
++       unsigned long load = this_rq->load.weight;
++       unsigned long pending_updates;
++
++       /*
++        * Bloody broken means of dealing with nohz, but better than nothing..
++        * jiffies is updated by one cpu, another cpu can drift wrt the jiffy
++        * update and see 0 difference the one time and 2 the next, even though
++        * we ticked at roughtly the same rate.
++        *
++        * Hence we only use this from nohz_idle_balance() and skip this
++        * nonsense when called from the scheduler_tick() since that's
++        * guaranteed a stable rate.
++        */
++       if (load || curr_jiffies == this_rq->last_load_update_tick)
++               return;
++
++       pending_updates = curr_jiffies - this_rq->last_load_update_tick;
++       this_rq->last_load_update_tick = curr_jiffies;
++
++       __update_cpu_load(this_rq, load, pending_updates);
++}
++
++/*
++ * Called from scheduler_tick()
++ */
+ static void update_cpu_load_active(struct rq *this_rq)
+ {
+-       update_cpu_load(this_rq);
++       /*
++        * See the mess in update_idle_cpu_load().
++        */
++       this_rq->last_load_update_tick = jiffies;
++       __update_cpu_load(this_rq, this_rq->load.weight, 1);
+ 
+        calc_load_account_active(this_rq);
+ }
+diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
+index 8a39fa3..66e4576 100644
+--- a/kernel/sched_fair.c
++++ b/kernel/sched_fair.c
+@@ -4735,7 +4735,7 @@ static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle)
+ 
+                raw_spin_lock_irq(&this_rq->lock);
+                update_rq_clock(this_rq);
+-               update_cpu_load(this_rq);
++               update_idle_cpu_load(this_rq);
+                raw_spin_unlock_irq(&this_rq->lock);
+ 
+                rebalance_domains(balance_cpu, CPU_IDLE);
+-- 
+1.7.7.6
+