From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Peter Zijlstra <peterz@infradead.org>
Cc: kbuild test robot <lkp@intel.com>,
kbuild-all@01.org, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, Dmitry Vyukov <dvyukov@google.com>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH] locking/lockdep: Dump state of percpu_rwsem upon hung up.
Date: Tue, 10 Jul 2018 19:48:31 +0900 [thread overview]
Message-ID: <bdecb526-9f61-bdb9-85f1-a6243b5fac7a@i-love.sakura.ne.jp> (raw)
In-Reply-To: <20180710093046.GE2476@hirez.programming.kicks-ass.net>
On 2018/07/10 18:30, Peter Zijlstra wrote:
>> diff --git a/include/linux/rwsem-spinlock.h b/include/linux/rwsem-spinlock.h
>> index e475683..1164965 100644
>> --- a/include/linux/rwsem-spinlock.h
>> +++ b/include/linux/rwsem-spinlock.h
>> @@ -22,7 +22,7 @@
>> * - if wait_list is not empty, then there are processes waiting for the semaphore
>> */
>> struct rw_semaphore {
>> - __s32 count;
>> + atomic_long_t count;
>
> Uhhh... how does this even build? rwsem-spinlock.c doesn't use
> atomic_long primitives to change count.
Sorry, I forgot to build test rwsem-spinlock.c side.
>
> And the atomic_long count usage is completely private to rwsem-xadd.c,
> nothing outside of that should use that field, ever.
>
The reason I made above patch is to make
"[PATCH] locking/lockdep: Dump state of percpu_rwsem upon hung up." patch
possible to build on x86_64. Although "nothing outside of that should use
that field", I want to check "struct rw_semaphore"->count for isolating
the problem.
Should I update
"[PATCH] locking/lockdep: Dump state of percpu_rwsem upon hung up." side
to use "#ifndef CONFIG_RWSEM_GENERIC_SPINLOCK" ?
next prev parent reply other threads:[~2018-07-10 10:48 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-07 6:31 [PATCH] locking/lockdep: Dump state of percpu_rwsem upon hung up Tetsuo Handa
2018-07-07 11:31 ` kbuild test robot
2018-07-07 14:09 ` Tetsuo Handa
2018-07-10 6:10 ` Tetsuo Handa
2018-07-10 9:20 ` Will Deacon
2018-07-10 9:30 ` Peter Zijlstra
2018-07-10 10:48 ` Tetsuo Handa [this message]
2018-07-10 11:28 ` Peter Zijlstra
2018-07-10 9:41 ` [PATCH] locking/rwsem: Convert the other sem->count to 'atomic_long_t' kbuild test robot
2018-07-10 9:41 ` kbuild test robot
2018-07-10 11:47 ` [PATCH v2] locking/lockdep: Dump state of percpu_rwsem upon hung up Tetsuo Handa
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