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| author | John Kacur <jkacur@redhat.com> | 2011-09-19 11:09:27 +0200 |
|---|---|---|
| committer | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2016-02-13 00:36:09 +0100 |
| commit | ef6ac8404f8c8d1e19fca892a79004e936da3411 (patch) | |
| tree | 2d01bae5a63cef50e65583a204e8af5eefe558e5 | |
| parent | 3be37437a03fc3140fb1178f4b47ea400e77f2f1 (diff) | |
| download | rt-linux-ef6ac8404f8c8d1e19fca892a79004e936da3411.tar.gz | |
rwlocks: Fix section mismatch
This fixes the following build error for the preempt-rt kernel.
make kernel/fork.o
CC kernel/fork.o
kernel/fork.c:90: error: section of tasklist_lock conflicts with previous declaration
make[2]: *** [kernel/fork.o] Error 1
make[1]: *** [kernel/fork.o] Error 2
The rt kernel cache aligns the RWLOCK in DEFINE_RWLOCK by default.
The non-rt kernels explicitly cache align only the tasklist_lock in
kernel/fork.c
That can create a build conflict. This fixes the build problem by making the
non-rt kernels cache align RWLOCKs by default. The side effect is that
the other RWLOCKs are also cache aligned for non-rt.
This is a short term solution for rt only.
The longer term solution would be to push the cache aligned DEFINE_RWLOCK
to mainline. If there are objections, then we could create a
DEFINE_RWLOCK_CACHE_ALIGNED or something of that nature.
Signed-off-by: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/alpine.LFD.2.00.1109191104010.23118@localhost6.localdomain6
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | include/linux/rwlock_types.h | 3 | ||||
| -rw-r--r-- | kernel/fork.c | 2 |
2 files changed, 3 insertions, 2 deletions
diff --git a/include/linux/rwlock_types.h b/include/linux/rwlock_types.h index 5317cd95729275..d0da966ad7a0a9 100644 --- a/include/linux/rwlock_types.h +++ b/include/linux/rwlock_types.h @@ -47,6 +47,7 @@ typedef struct { RW_DEP_MAP_INIT(lockname) } #endif -#define DEFINE_RWLOCK(x) rwlock_t x = __RW_LOCK_UNLOCKED(x) +#define DEFINE_RWLOCK(name) \ + rwlock_t name __cacheline_aligned_in_smp = __RW_LOCK_UNLOCKED(name) #endif /* __LINUX_RWLOCK_TYPES_H */ diff --git a/kernel/fork.c b/kernel/fork.c index 6ad981b2186680..46c1e8342ad8bd 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -108,7 +108,7 @@ int max_threads; /* tunable limit on nr_threads */ DEFINE_PER_CPU(unsigned long, process_counts) = 0; -__cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ +DEFINE_RWLOCK(tasklist_lock); /* outer */ #ifdef CONFIG_PROVE_RCU int lockdep_tasklist_lock_is_held(void) |