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sched, timer: Convert usages of ACCESS_ONCE() in the scheduler to READ_ONCE()/WRITE_ONCE()

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ACCESS_ONCE doesn't work reliably on non-scalar types. This patch removes
the rest of the existing usages of ACCESS_ONCE() in the scheduler, and use
the new READ_ONCE() and WRITE_ONCE() APIs as appropriate.

Signed-off-by: Jason Low <jason.low2@hp.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Waiman Long <Waiman.Long@hp.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Aswin Chandramouleeswaran <aswin@hp.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1430251224-5764-2-git-send-email-jason.low2@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Jason Low
2015-04-28 13:00:20 -07:00
committed by Ingo Molnar
parent ce2f5fe463
commit 316c1608d1
12 changed files with 26 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
kernel/sched/fair.c
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@@ -834,7 +834,7 @@ static unsigned int task_nr_scan_windows(struct task_struct *p)
static unsigned int task_scan_min(struct task_struct *p)
{
unsigned int scan_size = ACCESS_ONCE(sysctl_numa_balancing_scan_size);
unsigned int scan_size = READ_ONCE(sysctl_numa_balancing_scan_size);
unsigned int scan, floor;
unsigned int windows = 1;
@@ -1794,7 +1794,7 @@ static void task_numa_placement(struct task_struct *p)
u64 runtime, period;
spinlock_t *group_lock = NULL;
seq = ACCESS_ONCE(p->mm->numa_scan_seq);
seq = READ_ONCE(p->mm->numa_scan_seq);
if (p->numa_scan_seq == seq)
return;
p->numa_scan_seq = seq;
@@ -1938,7 +1938,7 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
}
rcu_read_lock();
tsk = ACCESS_ONCE(cpu_rq(cpu)->curr);
tsk = READ_ONCE(cpu_rq(cpu)->curr);
if (!cpupid_match_pid(tsk, cpupid))
goto no_join;
@@ -2107,7 +2107,7 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
static void reset_ptenuma_scan(struct task_struct *p)
{
ACCESS_ONCE(p->mm->numa_scan_seq)++;
WRITE_ONCE(p->mm->numa_scan_seq, READ_ONCE(p->mm->numa_scan_seq) + 1);
p->mm->numa_scan_offset = 0;
}
@@ -4451,7 +4451,7 @@ static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
*/
static void update_idle_cpu_load(struct rq *this_rq)
{
unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
unsigned long curr_jiffies = READ_ONCE(jiffies);
unsigned long load = this_rq->cfs.runnable_load_avg;
unsigned long pending_updates;
@@ -4473,7 +4473,7 @@ static void update_idle_cpu_load(struct rq *this_rq)
void update_cpu_load_nohz(void)
{
struct rq *this_rq = this_rq();
unsigned long curr_jiffies = ACCESS_ONCE(jiffies);
unsigned long curr_jiffies = READ_ONCE(jiffies);
unsigned long pending_updates;
if (curr_jiffies == this_rq->last_load_update_tick)
@@ -4558,7 +4558,7 @@ static unsigned long capacity_orig_of(int cpu)
static unsigned long cpu_avg_load_per_task(int cpu)
{
struct rq *rq = cpu_rq(cpu);
unsigned long nr_running = ACCESS_ONCE(rq->cfs.h_nr_running);
unsigned long nr_running = READ_ONCE(rq->cfs.h_nr_running);
unsigned long load_avg = rq->cfs.runnable_load_avg;
if (nr_running)
@@ -6220,8 +6220,8 @@ static unsigned long scale_rt_capacity(int cpu)
* Since we're reading these variables without serialization make sure
* we read them once before doing sanity checks on them.
*/
age_stamp = ACCESS_ONCE(rq->age_stamp);
avg = ACCESS_ONCE(rq->rt_avg);
age_stamp = READ_ONCE(rq->age_stamp);
avg = READ_ONCE(rq->rt_avg);
delta = __rq_clock_broken(rq) - age_stamp;
if (unlikely(delta < 0))