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Re: [PATCH 1/4] Add single-thread.h header

Ping (x2).  This is mostly a refactor patch, no semantic changes
are expected.

On 09/04/2019 09:11, Adhemerval Zanella wrote:
> Ping.
> 
> On 22/02/2019 16:27, Adhemerval Zanella wrote:
>> This patch move the single-thread syscall optimization defintions from
>> syscall-cancel.h to new header file single-thread.h and also move the
>> cancellation definitions from pthreadP.h to syscall-cancel.h.
>>
>> The idea is just simplify the inclusion of both syscall-cancel.h and
>> single-thread.h (without the requirement of including all pthreadP.h
>> defintions).
>>
>> No semantic changes expected, checked on a build for all major ABIs.
>>
>> 	* nptl/pthreadP.h (CANCEL_ASYNC, CANCEL_RESET, LIBC_CANCEL_ASYNC,
>> 	LIBC_CANCEL_RESET, __libc_enable_asynccancel,
>> 	__libc_disable_asynccancel, __librt_enable_asynccancel,
>> 	__libc_disable_asynccancel, __librt_enable_asynccancel,
>> 	__librt_disable_asynccancel): Move to ...
>> 	* sysdeps/unix/sysv/linux/sysdep-cancel.h: ... here.
>> 	(SINGLE_THREAD_P, RTLD_SINGLE_THREAD_P): Move to ...
>> 	* sysdeps/unix/sysv/linux/single-thread.h: ... here.
>> 	* sysdeps/generic/single-thread.h: New file.
>> 	* sysdeps/unix/sysdep.h: Include single-thread.h.
>> 	* sysdeps/unix/sysv/linux/futex-internal.h: Include sysdep-cancel.h.
>> 	* sysdeps/unix/sysv/linux/lowlevellock-futex.h: Likewise.
>> ---
>>  nptl/pthreadP.h                              | 37 ---------
>>  sysdeps/generic/single-thread.h              | 24 ++++++
>>  sysdeps/unix/sysdep.h                        |  2 +-
>>  sysdeps/unix/sysv/linux/futex-internal.h     |  2 +-
>>  sysdeps/unix/sysv/linux/lowlevellock-futex.h |  2 +-
>>  sysdeps/unix/sysv/linux/single-thread.h      | 64 ++++++++++++++++
>>  sysdeps/unix/sysv/linux/sysdep-cancel.h      | 81 ++++++++++----------
>>  7 files changed, 133 insertions(+), 79 deletions(-)
>>  create mode 100644 sysdeps/generic/single-thread.h
>>  create mode 100644 sysdeps/unix/sysv/linux/single-thread.h
>>
>> diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h
>> index 626bd4b096..0beacd1266 100644
>> --- a/nptl/pthreadP.h
>> +++ b/nptl/pthreadP.h
>> @@ -311,34 +311,6 @@ __do_cancel (void)
>>  }
>>  
>>  
>> -/* Set cancellation mode to asynchronous.  */
>> -#define CANCEL_ASYNC() \
>> -  __pthread_enable_asynccancel ()
>> -/* Reset to previous cancellation mode.  */
>> -#define CANCEL_RESET(oldtype) \
>> -  __pthread_disable_asynccancel (oldtype)
>> -
>> -#if IS_IN (libc)
>> -/* Same as CANCEL_ASYNC, but for use in libc.so.  */
>> -# define LIBC_CANCEL_ASYNC() \
>> -  __libc_enable_asynccancel ()
>> -/* Same as CANCEL_RESET, but for use in libc.so.  */
>> -# define LIBC_CANCEL_RESET(oldtype) \
>> -  __libc_disable_asynccancel (oldtype)
>> -#elif IS_IN (libpthread)
>> -# define LIBC_CANCEL_ASYNC() CANCEL_ASYNC ()
>> -# define LIBC_CANCEL_RESET(val) CANCEL_RESET (val)
>> -#elif IS_IN (librt)
>> -# define LIBC_CANCEL_ASYNC() \
>> -  __librt_enable_asynccancel ()
>> -# define LIBC_CANCEL_RESET(val) \
>> -  __librt_disable_asynccancel (val)
>> -#else
>> -# define LIBC_CANCEL_ASYNC()	0 /* Just a dummy value.  */
>> -# define LIBC_CANCEL_RESET(val)	((void)(val)) /* Nothing, but evaluate it.  */
>> -#endif
>> -
>> -
>>  /* Internal prototypes.  */
>>  
>>  /* Thread list handling.  */
>> @@ -545,15 +517,6 @@ extern int __pthread_cond_wait_2_0 (pthread_cond_2_0_t *cond,
>>  extern int __pthread_getaffinity_np (pthread_t th, size_t cpusetsize,
>>  				     cpu_set_t *cpuset);
>>  
>> -/* The two functions are in libc.so and not exported.  */
>> -extern int __libc_enable_asynccancel (void) attribute_hidden;
>> -extern void __libc_disable_asynccancel (int oldtype) attribute_hidden;
>> -
>> -
>> -/* The two functions are in librt.so and not exported.  */
>> -extern int __librt_enable_asynccancel (void) attribute_hidden;
>> -extern void __librt_disable_asynccancel (int oldtype) attribute_hidden;
>> -
>>  #if IS_IN (libpthread)
>>  /* Special versions which use non-exported functions.  */
>>  extern void __pthread_cleanup_push (struct _pthread_cleanup_buffer *buffer,
>> diff --git a/sysdeps/generic/single-thread.h b/sysdeps/generic/single-thread.h
>> new file mode 100644
>> index 0000000000..0a1520ec49
>> --- /dev/null
>> +++ b/sysdeps/generic/single-thread.h
>> @@ -0,0 +1,24 @@
>> +/* Single thread optimization, generic version.
>> +   Copyright (C) 2019 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
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#ifndef _SINGLE_THREAD_H
>> +#define _SINGLE_THREAD_H
>> +
>> +#define SINGLE_THREAD_P (0)
>> +
>> +#endif /* _SINGLE_THREAD_H  */
>> diff --git a/sysdeps/unix/sysdep.h b/sysdeps/unix/sysdep.h
>> index 7cb6c89825..6e503d7688 100644
>> --- a/sysdeps/unix/sysdep.h
>> +++ b/sysdeps/unix/sysdep.h
>> @@ -16,7 +16,7 @@
>>     <http://www.gnu.org/licenses/>.  */
>>  
>>  #include <sysdeps/generic/sysdep.h>
>> -
>> +#include <single-thread.h>
>>  #include <sys/syscall.h>
>>  #define	HAVE_SYSCALLS
>>  
>> diff --git a/sysdeps/unix/sysv/linux/futex-internal.h b/sysdeps/unix/sysv/linux/futex-internal.h
>> index 55f0fab77c..501f993853 100644
>> --- a/sysdeps/unix/sysv/linux/futex-internal.h
>> +++ b/sysdeps/unix/sysv/linux/futex-internal.h
>> @@ -22,7 +22,7 @@
>>  #include <sysdeps/nptl/futex-internal.h>
>>  #include <errno.h>
>>  #include <lowlevellock-futex.h>
>> -#include <nptl/pthreadP.h>
>> +#include <sysdep-cancel.h>
>>  
>>  /* See sysdeps/nptl/futex-internal.h for documentation; this file only
>>     contains Linux-specific comments.
>> diff --git a/sysdeps/unix/sysv/linux/lowlevellock-futex.h b/sysdeps/unix/sysv/linux/lowlevellock-futex.h
>> index 6f060b1739..030a14b8dc 100644
>> --- a/sysdeps/unix/sysv/linux/lowlevellock-futex.h
>> +++ b/sysdeps/unix/sysv/linux/lowlevellock-futex.h
>> @@ -21,7 +21,7 @@
>>  
>>  #ifndef __ASSEMBLER__
>>  #include <sysdep.h>
>> -#include <tls.h>
>> +#include <sysdep-cancel.h>
>>  #include <kernel-features.h>
>>  #endif
>>  
>> diff --git a/sysdeps/unix/sysv/linux/single-thread.h b/sysdeps/unix/sysv/linux/single-thread.h
>> new file mode 100644
>> index 0000000000..8248c5d8b8
>> --- /dev/null
>> +++ b/sysdeps/unix/sysv/linux/single-thread.h
>> @@ -0,0 +1,64 @@
>> +/* Single thread optimization, Linux version.
>> +   Copyright (C) 2019 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
>> +   <http://www.gnu.org/licenses/>.  */
>> +
>> +#ifndef _SINGLE_THREAD_H
>> +#define _SINGLE_THREAD_H
>> +
>> +/* The default way to check if the process is single thread is by using the
>> +   pthread_t 'multiple_threads' field.  However for some architectures it
>> +   is faster to either use an extra field on TCB or global varibles
>> +   (the TCB field is also used on x86 for some single-thread atomic
>> +   optimizations).
>> +
>> +   The ABI might define SINGLE_THREAD_BY_GLOBAL to enable the single
>> +   thread check to use global variables instead of the pthread_t
>> +   field.  */
>> +
>> +#ifdef SINGLE_THREAD_BY_GLOBAL
>> +# if IS_IN (libc)
>> +extern int __libc_multiple_threads;
>> +#  define SINGLE_THREAD_P \
>> +  __glibc_likely (__libc_multiple_threads == 0)
>> +# elif IS_IN (libpthread)
>> +extern int __pthread_multiple_threads;
>> +#  define SINGLE_THREAD_P \
>> +  __glibc_likely (__pthread_multiple_threads == 0)
>> +# elif IS_IN (librt)
>> +#   define SINGLE_THREAD_P					\
>> +  __glibc_likely (THREAD_GETMEM (THREAD_SELF,			\
>> +				 header.multiple_threads) == 0)
>> +# else
>> +/* For rtld, et cetera.  */
>> +#  define SINGLE_THREAD_P (1)
>> +# endif
>> +#else /* SINGLE_THREAD_BY_GLOBAL  */
>> +# if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)
>> +#   define SINGLE_THREAD_P					\
>> +  __glibc_likely (THREAD_GETMEM (THREAD_SELF,			\
>> +				 header.multiple_threads) == 0)
>> +# else
>> +/* For rtld, et cetera.  */
>> +#  define SINGLE_THREAD_P (1)
>> +# endif
>> +#endif /* SINGLE_THREAD_BY_GLOBAL  */
>> +
>> +#define RTLD_SINGLE_THREAD_P \
>> +  __glibc_likely (THREAD_GETMEM (THREAD_SELF, \
>> +				 header.multiple_threads) == 0)
>> +
>> +#endif /* _SINGLE_THREAD_H  */
>> diff --git a/sysdeps/unix/sysv/linux/sysdep-cancel.h b/sysdeps/unix/sysv/linux/sysdep-cancel.h
>> index 896549c7f7..a831b30106 100644
>> --- a/sysdeps/unix/sysv/linux/sysdep-cancel.h
>> +++ b/sysdeps/unix/sysv/linux/sysdep-cancel.h
>> @@ -17,48 +17,51 @@
>>     License along with the GNU C Library; if not, see
>>     <http://www.gnu.org/licenses/>.  */
>>  
>> +#ifndef _SYSDEP_CANCEL_H
>> +#define _SYSDEP_CANCEL_H
>> +
>>  #include <sysdep.h>
>>  #include <tls.h>
>> -#include <nptl/pthreadP.h>
>> +#include <errno.h>
>> +
>> +/* The two functions are in libc.so and not exported.  */
>> +extern int __libc_enable_asynccancel (void) attribute_hidden;
>> +extern void __libc_disable_asynccancel (int oldtype) attribute_hidden;
>> +
>> +/* The two functions are in librt.so and not exported.  */
>> +extern int __librt_enable_asynccancel (void) attribute_hidden;
>> +extern void __librt_disable_asynccancel (int oldtype) attribute_hidden;
>> +
>> +/* The two functions are in libpthread.so and not exported.  */
>> +extern int __pthread_enable_asynccancel (void) attribute_hidden;
>> +extern void __pthread_disable_asynccancel (int oldtype) attribute_hidden;
>>  
>> -/* The default way to check if the process is single thread is by using the
>> -   pthread_t 'multiple_threads' field.  However for some architectures it
>> -   is faster to either use an extra field on TCB or global varibles
>> -   (the TCB field is also used on x86 for some single-thread atomic
>> -   optimizations).
>> +/* Set cancellation mode to asynchronous.  */
>> +#define CANCEL_ASYNC() \
>> +  __pthread_enable_asynccancel ()
>> +/* Reset to previous cancellation mode.  */
>> +#define CANCEL_RESET(oldtype) \
>> +  __pthread_disable_asynccancel (oldtype)
>>  
>> -   The ABI might define SINGLE_THREAD_BY_GLOBAL to enable the single
>> -   thread check to use global variables instead of the pthread_t
>> -   field.  */
>> +#if IS_IN (libc)
>> +/* Same as CANCEL_ASYNC, but for use in libc.so.  */
>> +# define LIBC_CANCEL_ASYNC() \
>> +  __libc_enable_asynccancel ()
>> +/* Same as CANCEL_RESET, but for use in libc.so.  */
>> +# define LIBC_CANCEL_RESET(oldtype) \
>> +  __libc_disable_asynccancel (oldtype)
>> +#elif IS_IN (libpthread)
>> +# define LIBC_CANCEL_ASYNC() CANCEL_ASYNC ()
>> +# define LIBC_CANCEL_RESET(val) CANCEL_RESET (val)
>> +#elif IS_IN (librt)
>> +# define LIBC_CANCEL_ASYNC() \
>> +  __librt_enable_asynccancel ()
>> +# define LIBC_CANCEL_RESET(val) \
>> +  __librt_disable_asynccancel (val)
>> +#else
>> +# define LIBC_CANCEL_ASYNC()	0 /* Just a dummy value.  */
>> +# define LIBC_CANCEL_RESET(val)	((void)(val)) /* Nothing, but evaluate it.  */
>> +#endif
>>  
>> -#ifdef SINGLE_THREAD_BY_GLOBAL
>> -# if IS_IN (libc)
>> -extern int __libc_multiple_threads;
>> -#  define SINGLE_THREAD_P \
>> -  __glibc_likely (__libc_multiple_threads == 0)
>> -# elif IS_IN (libpthread)
>> -extern int __pthread_multiple_threads;
>> -#  define SINGLE_THREAD_P \
>> -  __glibc_likely (__pthread_multiple_threads == 0)
>> -# elif IS_IN (librt)
>> -#   define SINGLE_THREAD_P					\
>> -  __glibc_likely (THREAD_GETMEM (THREAD_SELF,			\
>> -				 header.multiple_threads) == 0)
>> -# else
>> -/* For rtld, et cetera.  */
>> -#  define SINGLE_THREAD_P (1)
>> -# endif
>> -#else /* SINGLE_THREAD_BY_GLOBAL  */
>> -# if IS_IN (libc) || IS_IN (libpthread) || IS_IN (librt)
>> -#   define SINGLE_THREAD_P					\
>> -  __glibc_likely (THREAD_GETMEM (THREAD_SELF,			\
>> -				 header.multiple_threads) == 0)
>> -# else
>> -/* For rtld, et cetera.  */
>> -#  define SINGLE_THREAD_P (1)
>> -# endif
>> -#endif /* SINGLE_THREAD_BY_GLOBAL  */
>>  
>> -#define RTLD_SINGLE_THREAD_P \
>> -  __glibc_likely (THREAD_GETMEM (THREAD_SELF, \
>> -				 header.multiple_threads) == 0)
>> +#endif
>>
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