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Re: [PATCH 3/3] Add runtime check for __ASSUME_REQUEUE_PI (BZ#18463)
- From: Adhemerval Zanella <adhemerval dot zanella at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Thu, 2 Jun 2016 14:47:18 -0300
- Subject: Re: [PATCH 3/3] Add runtime check for __ASSUME_REQUEUE_PI (BZ#18463)
- Authentication-results: sourceware.org; auth=none
- References: <1463608638-7215-1-git-send-email-adhemerval dot zanella at linaro dot org> <1463608638-7215-3-git-send-email-adhemerval dot zanella at linaro dot org> <5744A658 dot 7030904 at linaro dot org>
Ping.
On 24/05/2016 16:07, Adhemerval Zanella wrote:
> I am sending a new version of this patch because now prio_inherit_missing
> is non longer static inline function, its name causes namespace pollution.
> Main change from previous version is just the new name scheme by prepending
> a double underscore.
>
> --
>
> Tested on ARM (v3.8 kernel) and x86_64.
>
> * nptl/pthreadP.h (prio_inherit_missing): Change name to
> __prio_inherit_missing.
> (USE_REQUEUE_PI): Remove define.
> (use_requeue_pi): New function.
> * nptl/pthread_cond_broadcast.c [__ASSUME_REQUEUE_PI]
> (__pthread_cond_broadcast): Remove ifdef.
> (USE_REQUEUE_PI): Change to use_requeue_pi.
> * nptl/pthread_cond_signal.c [__ASSUME_REQUEUE_PI]
> (__pthread_cond_signal): Remove ifdef.
> (USE_REQUEUE_PI): Change to use_requeue_pi.
> * nptl/pthread_cond_timedwait.c [__ASSUME_REQUEUE_PI]
> (__pthread_cond_timedwait): Remove ifdef.
> (USE_REQUEUE_PI): Change to use_requeue_pi.
> ( nptl/pthread_cond_wait.c [__ASSUME_REQUEUE_PI]
> (__pthread_cond_wait): Remove ifdef.
> (USE_REQUEUE_PI): Change to use_requeue_pi.
> * nptl/pthread_mutex_init.c (prio_inherit_missing): Remove 'static'
> qualifier and change name to __prio_inherit_missing.
> ---
> nptl/pthreadP.h | 23 ++++++++++++++---------
> nptl/pthread_cond_broadcast.c | 5 ++---
> nptl/pthread_cond_signal.c | 5 ++---
> nptl/pthread_cond_timedwait.c | 11 ++++-------
> nptl/pthread_cond_wait.c | 13 +++++--------
> nptl/pthread_mutex_init.c | 7 ++++---
> 7 files changed, 50 insertions(+), 33 deletions(-)
>
> diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
> index d479a3e..e53f649 100644
> --- a/nptl/pthreadP.h
> +++ b/nptl/pthreadP.h
> @@ -585,17 +585,22 @@ extern void __wait_lookup_done (void) attribute_hidden;
> # define PTHREAD_STATIC_FN_REQUIRE(name) __asm (".globl " #name);
> #endif
>
> +extern bool prio_inherit_missing (void);
> +
> /* Test if the mutex is suitable for the FUTEX_WAIT_REQUEUE_PI operation. */
> -#if (defined lll_futex_wait_requeue_pi \
> - && defined __ASSUME_REQUEUE_PI)
> -# define USE_REQUEUE_PI(mut) \
> - ((mut) && (mut) != (void *) ~0l \
> - && (((mut)->__data.__kind \
> - & (PTHREAD_MUTEX_PRIO_INHERIT_NP | PTHREAD_MUTEX_ROBUST_NORMAL_NP)) \
> - == PTHREAD_MUTEX_PRIO_INHERIT_NP))
> -#else
> -# define USE_REQUEUE_PI(mut) 0
> +static inline bool
> +use_requeue_pi (pthread_mutex_t *mut)
> +{
> +#ifndef __ASSUME_REQUEUE_PI
> + if (__prio_inherit_missing ())
> + return false;
> #endif
> + return (mut) &&
> + (mut) != (void *) ~0l &&
> + (((mut)->__data.__kind
> + & (PTHREAD_MUTEX_PRIO_INHERIT_NP | PTHREAD_MUTEX_ROBUST_NORMAL_NP)) ==
> + PTHREAD_MUTEX_PRIO_INHERIT_NP);
> +}
>
> /* Returns 0 if POL is a valid scheduling policy. */
> static inline int
> diff --git a/nptl/pthread_cond_broadcast.c b/nptl/pthread_cond_broadcast.c
> index 552fd42..ef81bcd 100644
> --- a/nptl/pthread_cond_broadcast.c
> +++ b/nptl/pthread_cond_broadcast.c
> @@ -60,9 +60,8 @@ __pthread_cond_broadcast (pthread_cond_t *cond)
> || PTHREAD_MUTEX_PSHARED (mut) & PTHREAD_MUTEX_PSHARED_BIT)
> goto wake_all;
>
> -#if (defined lll_futex_cmp_requeue_pi \
> - && defined __ASSUME_REQUEUE_PI)
> - if (USE_REQUEUE_PI (mut))
> +#ifdef lll_futex_cmp_requeue_pi
> + if (use_requeue_pi (mut))
> {
> if (lll_futex_cmp_requeue_pi (&cond->__data.__futex, 1, INT_MAX,
> &mut->__data.__lock, futex_val,
> diff --git a/nptl/pthread_cond_signal.c b/nptl/pthread_cond_signal.c
> index b3a6d3d..9c8f883 100644
> --- a/nptl/pthread_cond_signal.c
> +++ b/nptl/pthread_cond_signal.c
> @@ -46,11 +46,10 @@ __pthread_cond_signal (pthread_cond_t *cond)
> ++cond->__data.__wakeup_seq;
> ++cond->__data.__futex;
>
> -#if (defined lll_futex_cmp_requeue_pi \
> - && defined __ASSUME_REQUEUE_PI)
> +#ifdef lll_futex_cmp_requeue_pi
> pthread_mutex_t *mut = cond->__data.__mutex;
>
> - if (USE_REQUEUE_PI (mut)
> + if (use_requeue_pi (mut)
> /* This can only really fail with a ENOSYS, since nobody can modify
> futex while we have the cond_lock. */
> && lll_futex_cmp_requeue_pi (&cond->__data.__futex, 1, 0,
> diff --git a/nptl/pthread_cond_timedwait.c b/nptl/pthread_cond_timedwait.c
> index 711a51d..61a651c 100644
> --- a/nptl/pthread_cond_timedwait.c
> +++ b/nptl/pthread_cond_timedwait.c
> @@ -63,8 +63,7 @@ __pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
> int pshared = (cond->__data.__mutex == (void *) ~0l)
> ? LLL_SHARED : LLL_PRIVATE;
>
> -#if (defined lll_futex_timed_wait_requeue_pi \
> - && defined __ASSUME_REQUEUE_PI)
> +#ifdef lll_futex_timed_wait_requeue_pi
> int pi_flag = 0;
> #endif
>
> @@ -161,8 +160,7 @@ __pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
>
> /* REQUEUE_PI was implemented after FUTEX_CLOCK_REALTIME, so it is sufficient
> to check just the former. */
> -#if (defined lll_futex_timed_wait_requeue_pi \
> - && defined __ASSUME_REQUEUE_PI)
> +#ifdef lll_futex_timed_wait_requeue_pi
> /* If pi_flag remained 1 then it means that we had the lock and the mutex
> but a spurious waker raced ahead of us. Give back the mutex before
> going into wait again. */
> @@ -171,7 +169,7 @@ __pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
> __pthread_mutex_cond_lock_adjust (mutex);
> __pthread_mutex_unlock_usercnt (mutex, 0);
> }
> - pi_flag = USE_REQUEUE_PI (mutex);
> + pi_flag = use_requeue_pi (mutex);
>
> if (pi_flag)
> {
> @@ -250,8 +248,7 @@ __pthread_cond_timedwait (pthread_cond_t *cond, pthread_mutex_t *mutex,
> __pthread_cleanup_pop (&buffer, 0);
>
> /* Get the mutex before returning. */
> -#if (defined lll_futex_timed_wait_requeue_pi \
> - && defined __ASSUME_REQUEUE_PI)
> +#ifdef lll_futex_timed_wait_requeue_pi
> if (pi_flag)
> {
> __pthread_mutex_cond_lock_adjust (mutex);
> diff --git a/nptl/pthread_cond_wait.c b/nptl/pthread_cond_wait.c
> index 3f62acc..f79bf67 100644
> --- a/nptl/pthread_cond_wait.c
> +++ b/nptl/pthread_cond_wait.c
> @@ -86,7 +86,7 @@ __condvar_cleanup (void *arg)
>
> /* Get the mutex before returning unless asynchronous cancellation
> is in effect. We don't try to get the mutex if we already own it. */
> - if (!(USE_REQUEUE_PI (cbuffer->mutex))
> + if (!(use_requeue_pi (cbuffer->mutex))
> || ((cbuffer->mutex->__data.__lock & FUTEX_TID_MASK)
> != THREAD_GETMEM (THREAD_SELF, tid)))
> {
> @@ -106,8 +106,7 @@ __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex)
> int pshared = (cond->__data.__mutex == (void *) ~0l)
> ? LLL_SHARED : LLL_PRIVATE;
>
> -#if (defined lll_futex_wait_requeue_pi \
> - && defined __ASSUME_REQUEUE_PI)
> +#ifdef lll_futex_wait_requeue_pi
> int pi_flag = 0;
> #endif
>
> @@ -160,8 +159,7 @@ __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex)
> /* Enable asynchronous cancellation. Required by the standard. */
> cbuffer.oldtype = __pthread_enable_asynccancel ();
>
> -#if (defined lll_futex_wait_requeue_pi \
> - && defined __ASSUME_REQUEUE_PI)
> +#ifdef lll_futex_wait_requeue_pi
> /* If pi_flag remained 1 then it means that we had the lock and the mutex
> but a spurious waker raced ahead of us. Give back the mutex before
> going into wait again. */
> @@ -170,7 +168,7 @@ __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex)
> __pthread_mutex_cond_lock_adjust (mutex);
> __pthread_mutex_unlock_usercnt (mutex, 0);
> }
> - pi_flag = USE_REQUEUE_PI (mutex);
> + pi_flag = use_requeue_pi (mutex);
>
> if (pi_flag)
> {
> @@ -221,8 +219,7 @@ __pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex)
> __pthread_cleanup_pop (&buffer, 0);
>
> /* Get the mutex before returning. Not needed for PI. */
> -#if (defined lll_futex_wait_requeue_pi \
> - && defined __ASSUME_REQUEUE_PI)
> +#ifdef lll_futex_wait_requeue_pi
> if (pi_flag)
> {
> __pthread_mutex_cond_lock_adjust (mutex);
> diff --git a/nptl/pthread_mutex_init.c b/nptl/pthread_mutex_init.c
> index 6aef890..c37f623 100644
> --- a/nptl/pthread_mutex_init.c
> +++ b/nptl/pthread_mutex_init.c
> @@ -33,8 +33,9 @@ static const struct pthread_mutexattr default_mutexattr =
> };
>
>
> -static bool
> -prio_inherit_missing (void)
> +bool
> +attribute_hidden
> +__prio_inherit_missing (void)
> {
> #ifdef __NR_futex
> static int tpi_supported;
> @@ -72,7 +73,7 @@ __pthread_mutex_init (pthread_mutex_t *mutex,
> break;
>
> case PTHREAD_PRIO_INHERIT << PTHREAD_MUTEXATTR_PROTOCOL_SHIFT:
> - if (__glibc_unlikely (prio_inherit_missing ()))
> + if (__glibc_unlikely (__prio_inherit_missing ()))
> return ENOTSUP;
> break;
>
>