Re: [PATCH v3 11/37] nptl: Move internal __nptl_nthreads variable into libc

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

LGTM with just a nit with a spurious change.

Reviewed-by: Adhemerval Zanella   <adhemerval.zanella@linaro.org>

On 16/03/2021 14:29, Florian Weimer via Libc-alpha wrote:
> ---
>  nptl/Makefile                       |  1 +
>  nptl/Versions                       |  1 +
>  nptl/libc_pthread_init.c            |  1 -
>  nptl/nptl-init.c                    |  1 -
>  nptl/nptl_nthreads.c                | 23 +++++++++++++++++++++++
>  nptl/pthreadP.h                     |  3 ++-
>  nptl/pthread_create.c               |  4 ----
>  nptl_db/structs.def                 |  2 +-
>  sysdeps/nptl/libc_start_call_main.h | 13 ++-----------
>  sysdeps/nptl/pthread-functions.h    |  2 --
>  10 files changed, 30 insertions(+), 21 deletions(-)
>  create mode 100644 nptl/nptl_nthreads.c
> 
> diff --git a/nptl/Makefile b/nptl/Makefile
> index c1ade91a0b..d7491632b8 100644
> --- a/nptl/Makefile
> +++ b/nptl/Makefile
> @@ -45,6 +45,7 @@ routines = \
>    libc_multiple_threads \
>    libc_pthread_init \
>    lowlevellock \
> +  nptl_nthreads \
>    old_pthread_cond_destroy \
>    old_pthread_cond_init \
>    pthread_atfork \

Ok.

> diff --git a/nptl/Versions b/nptl/Versions
> index 8f1cd3f7c4..968c4fba35 100644
> --- a/nptl/Versions
> +++ b/nptl/Versions
> @@ -107,6 +107,7 @@ libc {
>      __lll_lock_wait_private;
>      __lll_trylock_elision;
>      __lll_unlock_elision;
> +    __nptl_nthreads;
>      __pthread_attr_copy;
>      __pthread_attr_destroy;
>      __pthread_attr_init;

Ok.

> diff --git a/nptl/libc_pthread_init.c b/nptl/libc_pthread_init.c
> index 3ac54aae13..85fceff930 100644
> --- a/nptl/libc_pthread_init.c
> +++ b/nptl/libc_pthread_init.c
> @@ -27,7 +27,6 @@
>  #include <sysdep.h>
>  #include <ldsodefs.h>
>  
> -
>  #ifdef TLS_MULTIPLE_THREADS_IN_TCB
>  void
>  #else

Spurious line removal.

> diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c
> index d30e8a9bdf..a09d6ed306 100644
> --- a/nptl/nptl-init.c
> +++ b/nptl/nptl-init.c
> @@ -94,7 +94,6 @@ static const struct pthread_functions pthread_functions =
>      .ptr___pthread_key_create = __pthread_key_create,
>      .ptr___pthread_getspecific = __pthread_getspecific,
>      .ptr___pthread_setspecific = __pthread_setspecific,
> -    .ptr_nthreads = &__nptl_nthreads,
>      .ptr__nptl_deallocate_tsd = __nptl_deallocate_tsd,
>      .ptr__nptl_setxid = __nptl_setxid,
>      .ptr_set_robust = __nptl_set_robust

Ok.

> diff --git a/nptl/nptl_nthreads.c b/nptl/nptl_nthreads.c
> new file mode 100644
> index 0000000000..2245bb3c76
> --- /dev/null
> +++ b/nptl/nptl_nthreads.c
> @@ -0,0 +1,23 @@
> +/* Thread counter variable.
> +   Copyright (C) 2021 Free Software Foundation, Inc.
> +   This file is part of the GNU C Library.
> +
> +   The GNU C Library is free software; you can redistribute it and/or
> +   modify it under the terms of the GNU Lesser General Public
> +   License as published by the Free Software Foundation; either
> +   version 2.1 of the License, or (at your option) any later version.
> +
> +   The GNU C Library is distributed in the hope that it will be useful,
> +   but WITHOUT ANY WARRANTY; without even the implied warranty of
> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> +   Lesser General Public License for more details.
> +
> +   You should have received a copy of the GNU Lesser General Public
> +   License along with the GNU C Library; if not, see
> +   <https://www.gnu.org/licenses/>.  */
> +
> +#include <pthreadP.h>
> +
> +/* Number of threads running.  */
> +unsigned int __nptl_nthreads = 1;
> +libc_hidden_data_def (__nptl_nthreads)

Ok.

> diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
> index f78bf03a52..b136aeae4d 100644
> --- a/nptl/pthreadP.h
> +++ b/nptl/pthreadP.h
> @@ -220,7 +220,8 @@ extern struct pthread_key_struct __pthread_keys[PTHREAD_KEYS_MAX];
>  hidden_proto (__pthread_keys)
>  
>  /* Number of threads running.  */
> -extern unsigned int __nptl_nthreads attribute_hidden;
> +extern unsigned int __nptl_nthreads;
> +libc_hidden_proto (__nptl_nthreads)
>  
>  #ifndef __ASSUME_SET_ROBUST_LIST
>  /* Negative if we do not have the system call and we can use it.  */

Ok.

> diff --git a/nptl/pthread_create.c b/nptl/pthread_create.c
> index 6c645aff48..350bf03f5d 100644
> --- a/nptl/pthread_create.c
> +++ b/nptl/pthread_create.c
> @@ -51,10 +51,6 @@ static td_thr_events_t __nptl_threads_events __attribute_used__;
>  /* Pointer to descriptor with the last event.  */
>  static struct pthread *__nptl_last_event __attribute_used__;
>  
> -/* Number of threads running.  */
> -unsigned int __nptl_nthreads = 1;
> -
> -
>  /* Code to allocate and deallocate a stack.  */
>  #include "allocatestack.c"
>  

Ok.

> diff --git a/nptl_db/structs.def b/nptl_db/structs.def
> index 999a9fc35a..d0e1cb659a 100644
> --- a/nptl_db/structs.def
> +++ b/nptl_db/structs.def
> @@ -73,7 +73,7 @@ DB_SYMBOL (nptl_version)
>  DB_FUNCTION (__nptl_create_event)
>  DB_FUNCTION (__nptl_death_event)
>  DB_SYMBOL (__nptl_threads_events)
> -DB_VARIABLE (__nptl_nthreads)
> +DB_MAIN_VARIABLE (__nptl_nthreads)
>  DB_VARIABLE (__nptl_last_event)
>  DB_VARIABLE (__nptl_initial_report_events)
>  

Ok.

> diff --git a/sysdeps/nptl/libc_start_call_main.h b/sysdeps/nptl/libc_start_call_main.h
> index 5218e7ab1e..112cc20a7a 100644
> --- a/sysdeps/nptl/libc_start_call_main.h
> +++ b/sysdeps/nptl/libc_start_call_main.h
> @@ -17,6 +17,7 @@
>     <https://www.gnu.org/licenses/>.  */
>  
>  #include <atomic.h>
> +#include <nptl/pthreadP.h>
>  
>  _Noreturn static void
>  __libc_start_call_main (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
> @@ -69,17 +70,7 @@ __libc_start_call_main (int (*main) (int, char **, char ** MAIN_AUXVEC_DECL),
>        /* One less thread.  Decrement the counter.  If it is zero we
>           terminate the entire process.  */
>        result = 0;
> -# ifdef SHARED
> -      unsigned int *ptr = __libc_pthread_functions.ptr_nthreads;
> -#  ifdef PTR_DEMANGLE
> -      PTR_DEMANGLE (ptr);
> -#  endif
> -# else
> -      extern unsigned int __nptl_nthreads __attribute ((weak));
> -      unsigned int *const ptr = &__nptl_nthreads;
> -# endif
> -
> -      if (! atomic_decrement_and_test (ptr))
> +      if (! atomic_decrement_and_test (&__nptl_nthreads))
>          /* Not much left to do but to exit the thread, not the process.  */
>          __exit_thread ();
>      }

Ok.

> diff --git a/sysdeps/nptl/pthread-functions.h b/sysdeps/nptl/pthread-functions.h
> index 280655fe40..2fa698b1da 100644
> --- a/sysdeps/nptl/pthread-functions.h
> +++ b/sysdeps/nptl/pthread-functions.h
> @@ -55,8 +55,6 @@ struct pthread_functions
>    int (*ptr___pthread_key_create) (pthread_key_t *, void (*) (void *));
>    void *(*ptr___pthread_getspecific) (pthread_key_t);
>    int (*ptr___pthread_setspecific) (pthread_key_t, const void *);
> -#define HAVE_PTR_NTHREADS
> -  unsigned int *ptr_nthreads;
>    void (*ptr__nptl_deallocate_tsd) (void);
>    int (*ptr__nptl_setxid) (struct xid_command *);
>    void (*ptr_set_robust) (struct pthread *);
> 

Ok.