From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-tip-commits@vger.kernel.org,
Ingo Molnar <mingo@kernel.org>,
x86@kernel.org
Subject: Re: [tip: locking/urgent] locking/ww_mutex: Treat ww_mutex_lock() like a trylock
Date: Wed, 17 Mar 2021 18:45:35 +0100 [thread overview]
Message-ID: <YFJAP8x917Ef0Khj@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YFI/C4VZuWjyHLNK@hirez.programming.kicks-ass.net>
On Wed, Mar 17, 2021 at 06:40:27PM +0100, Peter Zijlstra wrote:
> On Wed, Mar 17, 2021 at 05:48:48PM +0100, Peter Zijlstra wrote:
>
> > I think you'll find that if you use ww_mutex_init() it'll all work. Let
> > me go and zap this patch, and then I'll try and figure out why
> > DEFINE_WW_MUTEX() is buggered.
>
> Moo, I can't get the compiler to do as I want :/
>
> The below is so close but doesn't actually compile.. Maybe we should
> just give up on DEFINE_WW_MUTEX and simply remove it.
>
> ---
> diff --git a/include/linux/mutex.h b/include/linux/mutex.h
> index 0cd631a19727..85f50538f26a 100644
> --- a/include/linux/mutex.h
> +++ b/include/linux/mutex.h
> @@ -129,12 +129,15 @@ do { \
> # define __DEP_MAP_MUTEX_INITIALIZER(lockname)
> #endif
>
> -#define __MUTEX_INITIALIZER(lockname) \
> +#define ___MUTEX_INITIALIZER(lockname, depmap) \
> { .owner = ATOMIC_LONG_INIT(0) \
> , .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
> , .wait_list = LIST_HEAD_INIT(lockname.wait_list) \
> __DEBUG_MUTEX_INITIALIZER(lockname) \
> - __DEP_MAP_MUTEX_INITIALIZER(lockname) }
> + depmap }
> +
> +#define __MUTEX_INITIALIZER(lockname) \
> + ___MUTEX_INITIALIZER(lockname, __DEP_MAP_MUTEX_INITIALIZER(lockname))
>
> #define DEFINE_MUTEX(mutexname) \
> struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
> diff --git a/include/linux/ww_mutex.h b/include/linux/ww_mutex.h
> index 6ecf2a0220db..c62a030652b4 100644
> --- a/include/linux/ww_mutex.h
> +++ b/include/linux/ww_mutex.h
> @@ -50,9 +50,17 @@ struct ww_acquire_ctx {
>
> #ifdef CONFIG_DEBUG_LOCK_ALLOC
> # define __WW_CLASS_MUTEX_INITIALIZER(lockname, class) \
> - , .ww_class = class
> + , .ww_class = &(class)
> +
> +# define __DEP_MAP_WW_MUTEX_INITIALIZER(lockname, class) \
> + , .dep_map = { \
> + .key = &(class).mutex_key, \
> + .name = (class).mutex_name, \
,name = #class "_mutex", \
and it 'works', but shees!
> + .wait_type_inner = LD_WAIT_SLEEP, \
> + }
> #else
> # define __WW_CLASS_MUTEX_INITIALIZER(lockname, class)
> +# define __DEP_MAP_WW_MUTEX_INITIALIZER(lockname, class)
> #endif
>
> #define __WW_CLASS_INITIALIZER(ww_class, _is_wait_die) \
> @@ -62,7 +70,8 @@ struct ww_acquire_ctx {
> , .is_wait_die = _is_wait_die }
>
> #define __WW_MUTEX_INITIALIZER(lockname, class) \
> - { .base = __MUTEX_INITIALIZER(lockname.base) \
> + { .base = ___MUTEX_INITIALIZER(lockname.base, \
> + __DEP_MAP_WW_MUTEX_INITIALIZER(lockname.base, class)) \
> __WW_CLASS_MUTEX_INITIALIZER(lockname, class) }
>
> #define DEFINE_WD_CLASS(classname) \
> diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> index 0ab94e1f1276..e8305233eb0b 100644
> --- a/kernel/locking/locktorture.c
> +++ b/kernel/locking/locktorture.c
> @@ -358,9 +358,9 @@ static struct lock_torture_ops mutex_lock_ops = {
>
> #include <linux/ww_mutex.h>
> static DEFINE_WD_CLASS(torture_ww_class);
> -static DEFINE_WW_MUTEX(torture_ww_mutex_0, &torture_ww_class);
> -static DEFINE_WW_MUTEX(torture_ww_mutex_1, &torture_ww_class);
> -static DEFINE_WW_MUTEX(torture_ww_mutex_2, &torture_ww_class);
> +static DEFINE_WW_MUTEX(torture_ww_mutex_0, torture_ww_class);
> +static DEFINE_WW_MUTEX(torture_ww_mutex_1, torture_ww_class);
> +static DEFINE_WW_MUTEX(torture_ww_mutex_2, torture_ww_class);
>
> static int torture_ww_mutex_lock(void)
> __acquires(torture_ww_mutex_0)
next prev parent reply other threads:[~2021-03-17 17:46 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 15:31 [PATCH 0/4] locking/ww_mutex: Fix locktorture ww_mutex test problems Waiman Long
2021-03-16 15:31 ` [PATCH 1/4] locking/ww_mutex: Simplify use_ww_ctx & ww_ctx handling Waiman Long
2021-03-16 18:55 ` Davidlohr Bueso
2021-03-17 12:38 ` [tip: locking/urgent] " tip-bot2 for Waiman Long
2021-03-17 12:59 ` Peter Zijlstra
2021-03-17 13:43 ` Waiman Long
2021-03-17 13:55 ` Peter Zijlstra
2021-03-17 14:10 ` Waiman Long
2021-03-17 14:17 ` Peter Zijlstra
2021-03-17 14:33 ` Waiman Long
2021-03-16 15:31 ` [PATCH 2/4] locking/ww_mutex: Fix acquire/release imbalance in ww_acquire_init()/ww_acquire_fini() Waiman Long
2021-03-17 12:38 ` [tip: locking/urgent] " tip-bot2 for Waiman Long
2021-03-16 15:31 ` [PATCH 3/4] locking/ww_mutex: Treat ww_mutex_lock() like a trylock Waiman Long
2021-03-17 3:01 ` Davidlohr Bueso
2021-03-17 12:38 ` [tip: locking/urgent] " tip-bot2 for Waiman Long
2021-03-17 13:12 ` Peter Zijlstra
2021-03-17 13:31 ` Peter Zijlstra
2021-03-17 14:03 ` Waiman Long
2021-03-17 15:35 ` Waiman Long
2021-03-17 16:48 ` Peter Zijlstra
2021-03-17 17:40 ` Peter Zijlstra
2021-03-17 17:45 ` Peter Zijlstra [this message]
2021-03-17 18:32 ` Waiman Long
2021-03-17 19:58 ` Peter Zijlstra
2021-03-17 20:20 ` Waiman Long
2021-03-17 18:14 ` Waiman Long
2021-03-18 2:24 ` [PATCH 3/4] " Boqun Feng
2021-03-18 2:54 ` Waiman Long
2021-03-18 6:36 ` Boqun Feng
2021-03-16 15:31 ` [PATCH 4/4] locking/locktorture: Fix incorrect use of ww_acquire_ctx in ww_mutex test Waiman Long
2021-03-17 5:16 ` Davidlohr Bueso
2021-03-17 13:21 ` Waiman Long
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YFJAP8x917Ef0Khj@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-tip-commits@vger.kernel.org \
--cc=longman@redhat.com \
--cc=mingo@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).