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sched: Introduce preempt_count accessor functions

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Replace the single preempt_count() 'function' that's an lvalue with
two proper functions:

 preempt_count() - returns the preempt_count value as rvalue
 preempt_count_set() - Allows setting the preempt-count value

Also provide preempt_count_ptr() as a convenience wrapper to implement
all modifying operations.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-orxrbycjozopqfhb4dxdkdvb@git.kernel.org
[ Fixed build failure. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra
2013-09-25 14:07:32 +02:00
committed by Ingo Molnar
parent ea81174789
commit 4a2b4b2227
7 changed files with 30 additions and 18 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/sched/core.c
+2 -2
View File
@@ -2219,7 +2219,7 @@ void __kprobes add_preempt_count(int val)
if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
return;
#endif
preempt_count() += val;
add_preempt_count_notrace(val);
#ifdef CONFIG_DEBUG_PREEMPT
/*
* Spinlock count overflowing soon?
@@ -2250,7 +2250,7 @@ void __kprobes sub_preempt_count(int val)
if (preempt_count() == val)
trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
preempt_count() -= val;
sub_preempt_count_notrace(val);
}
EXPORT_SYMBOL(sub_preempt_count);
kernel/softirq.c
+2 -2
View File
@@ -106,7 +106,7 @@ static void __local_bh_disable(unsigned long ip, unsigned int cnt)
* We must manually increment preempt_count here and manually
* call the trace_preempt_off later.
*/
preempt_count() += cnt;
add_preempt_count_notrace(cnt);
/*
* Were softirqs turned off above:
*/
@@ -256,7 +256,7 @@ restart:
" exited with %08x?\n", vec_nr,
softirq_to_name[vec_nr], h->action,
prev_count, preempt_count());
preempt_count() = prev_count;
preempt_count_set(prev_count);
}
rcu_bh_qs(cpu);
kernel/timer.c
+4 -4
View File
@@ -1092,7 +1092,7 @@ static int cascade(struct tvec_base *base, struct tvec *tv, int index)
static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
unsigned long data)
{
int preempt_count = preempt_count();
int count = preempt_count();
#ifdef CONFIG_LOCKDEP
/*
@@ -1119,16 +1119,16 @@ static void call_timer_fn(struct timer_list *timer, void (*fn)(unsigned long),
lock_map_release(&lockdep_map);
if (preempt_count != preempt_count()) {
if (count != preempt_count()) {
WARN_ONCE(1, "timer: %pF preempt leak: %08x -> %08x\n",
fn, preempt_count, preempt_count());
fn, count, preempt_count());
/*
* Restore the preempt count. That gives us a decent
* chance to survive and extract information. If the
* callback kept a lock held, bad luck, but not worse
* than the BUG() we had.
*/
preempt_count() = preempt_count;
preempt_count_set(count);
}
}