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authorUlrich Drepper <drepper@redhat.com>2002-11-26 22:50:54 +0000
committerUlrich Drepper <drepper@redhat.com>2002-11-26 22:50:54 +0000
commit76a50749f7af5935ba3739e815aa6a16ae4440d1 (patch)
treec16eac47f220f03fea74d80ef0a4e774809e94b7 /nptl/DESIGN-sem.txt
parent6938e63f714b15c377d8cbf8e97b6f15b0e1b692 (diff)
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Initial revision cvs/initial
2002-11-26  Ulrich Drepper  <drepper@redhat.com>
	* allocatestack.c (queue_stack): Don't remove stack from list here.
	Do it in the caller.  Correct condition to prematurely terminate
	loop to free stacks.
	(__deallocate_stack): Remove stack from list here.
2002-11-26  Ulrich Drepper  <drepper@redhat.com>
	* Makefile (tests): Add tst-stack1.
	* tst-stack1.c: New file.
	* allocatestack.c (allocate_stack): Initialize the TCB on a user
	provided stack.
	* pthread_attr_getstack.c: Return bottom of the thread area.
2002-11-25  Ulrich Drepper  <drepper@redhat.com>
	* Makefile (libpthread-routines): Add pt-allocrtsig and
	pthread_kill_other_threads.
	* pt-allocrtsig.c: New file.
	* pthread_kill_other_threads.c: New file.
	* sysdeps/unix/sysv/linux/allocrtsig.c: Add additional aliases for
	all three functions.
	* sysdeps/unix/sysv/linux/Makefile (sysdep_routines): Remove
	allocrtsig.
	* sysdeps/unix/sysv/linux/Versions (libc:GLIBC_PRIVATE): Export
	__libc_current_sigrtmin_private, __libc_current_sigrtmax_private,
	and __libc_allocate_rtsig_private.
	* Versions (libpthread): Export pthread_kill_other_threads_np,
	__libc_current_sigrtmin, and __libc_current_sigrtmax.
2002-11-24  Ulrich Drepper  <drepper@redhat.com>

	* allocatestack.c (allocate_stack): stackaddr in attribute points to
	the end of the stack.  Adjust computations.
	When mprotect call fails dequeue stack and free it.
	* pthread_attr_setstack.c: Store top of the stack in stackaddr
	attribute.
	* pthread_getattr_np.c: Likewise.

	* descr.h (IS_DETACHED): Add some more parenthesis to prevent
	surprises.

2002-11-23  Ulrich Drepper  <drepper@redhat.com>

	* sysdeps/pthread/pthread.h (pthread_self): __THROW must come before
	attribute definitions.  Patch by Luca Barbieri <ldb@ldb.ods.org>.

2002-11-22  Ulrich Drepper  <drepper@redhat.com>

	* pthread_getspecific.c: Optimize access to first 2nd-level array.
	* pthread_setspecific.c: Likewise.

2002-11-21  Ulrich Drepper  <drepper@redhat.com>

	* sysdeps/unix/sysv/linux/i386/createthread.c: Remove CLONE_ flags
	definitions.  Get them from the official place.
	* sysdeps/unix/sysv/linux/i386/fork.c: Likewise.

	* sysdeps/unix/sysv/linux/i386/createthread.c: Update CLONE_* flags.
	Use new CLONE_ flags in clone() calls.

	* sysdeps/unix/sysv/linux/fork.c: Use ARCH_FORK to actually fork.
	* sysdeps/unix/sysv/linux/i386/fork.c: New file.

	* Versions: Add pthread_* functions for libc.
	* forward.c: New file.

	* sysdeps/pthread/Makefile (libpthread-sysdeps_routines): Add
	errno-loc.
	* herrno.c: New file.
	* res.c: New file.

	* Makefile (libpthread-routines): Remove sem_post, sem_wait,
	sem_trywait, and sem_timedwait.  Add herrno and res.
	* sem_init.c: Don't initialize lock and waiters members.
	* sem_open.c: Likewise.
	* sem_post.c: Removed.
	* sem_wait.c: Removed.
	* sem_trywait.c: Removed.
	* sem_timedwait.c: Removed.
	* sysdeps/unix/sysv/linux/i386/i486/lowlevelsem.S: Complete rewrite.
	Includes full implementations of sem_post, sem_wait, sem_trywait,
	and sem_timedwait.
	* sysdeps/unix/sysv/linux/i386/lowlevelsem.h (lll_sem_post): Adjust
	for new implementation.
	* sysdeps/unix/sysv/linux/internaltypes.h (struct sem): Remove lock
	and waiters fields.

	* tst-sem3.c: Improve error message.
	* tst-signal3.c: Likewise.

	* init.c (__pthread_initialize_minimal): Use set_tid_address syscall
	to tell the kernel about the termination futex and to initialize tid
	member.  Don't initialize main_thread.
	* descr.h (struct pthread): Remove main_thread member.
	* cancelllation.c (__do_cancel): Remove code handling main thread.
	The main thread is not special anymore.

	* allocatestack.c (__reclaim_stacks): Mark stacks as unused.  Add
	size of the stacks to stack_cache_actsize.

	* pt-readv.c: Add missing "defined".
	* pt-sigwait.c: Likewise.
	* pt-writev.c: Likewise.

2002-11-09  Ulrich Drepper  <drepper@redhat.com>

	* Versions: Export __connect from libpthread.
	Patch by Luca Barbieri <ldb@ldb.ods.org>.

	* Makefile (libpthread-routines): Add pt-raise.
	* sysdeps/unix/sysv/linux/raise.c: New file.
	* sysdeps/unix/sysv/linux/pt-raise.c: New file.
	* sysdeps/generic/pt-raise.c: New file.

	* pthread_cond_init.c: Initialize all data elements of the condvar
	structure.  Patch by Luca Barbieri <ldb@ldb.ods.org>.

	* pthread_attr_init.c: Actually implement 2.0 compatibility version.
	* pthread_create.c: Likewise.

	* Makefile (tests): Add tst-key1, tst-key2, tst-key3.
	* tst-key1.c: New file.
	* tst-key2.c: New file.
	* tst-key3.c: New file.

	* Versions: Export pthread_detach for version GLIBC_2.0.
	Reported by Saurabh Desai <sdesai@austin.ibm.com>.

2002-11-08  Ulrich Drepper  <drepper@redhat.com>

	* pthread_key_create.c: Terminate search after an unused key was found.
	Patch by Luca Barbieri <ldb@ldb.ods.org>.

	* sysdeps/unix/sysv/linux/i386/pthread_once.S: Return zero.
	Patch by Luca Barbieri <ldb@ldb.ods.org>.

2002-10-10  Ulrich Drepper  <drepper@redhat.com>

	* sysdeps/unix/sysv/linux/i386/i486/lowlevelsem.S: Use slow generic
	dynamic lookup for errno in PIC.

	* allocatestack.c (get_cached_stack): Rearrange code slightly to
	release the stack lock as soon as possible.
	Call _dl_allocate_tls_init for TCB from the cache to re-initialize
	the static TLS block.
	(allocate_stack): Call _dl_allocate_tls_init for user-provided stack.

	* cancellation.c: Renamed from cancelation.c.
	* Makefile: Adjust accordingly.
	* pthreadP.h (CANCELLATION_P): Renamed from CANCELATION_P.
	* cleanup_defer.c: Use CANCELLATION_P.
	* pthread_testcancel.c: Likewise.
	* descr.h: Fix spelling in comments.
	* init.c: Likewise.
	* pthread_getattr_np.c: Likewise.
	* pthread_getschedparam.c: Likewise.
	* pthread_setschedparam.c: Likewise.
	* Versions: Likewise.

	* pt-pselect.c: New file.
	* Makefile (libpthread-routines): Add pt-pselect.
	* Versions: Add pselect.

	* tst-cancel4.c: New file.
	* Makefile (tests): Add tst-cancel4.

2002-10-09  Ulrich Drepper  <drepper@redhat.com>

	* pthread_mutex_lock.c: Always record lock ownership.
	* pthread_mutex_timedlock.c: Likewise.
	* pthread_mutex_trylock.c: Likewise.

	* pt-readv.c: New file.
	* pt-writev.c: New file.
	* pt-creat.c: New file.
	* pt-msgrcv.c: New file.
	* pt-msgsnd.c: New file.
	* pt-poll.c: New file.
	* pt-select.c: New file.
	* pt-sigpause.c: New file.
	* pt-sigsuspend.c: New file.
	* pt-sigwait.c: New file.
	* pt-sigwaitinfo.c: New file.
	* pt-waitid.c: New file.
	* Makefile (libpthread-routines): Add pt-readv, pt-writev, pt-creat,
	pt-msgrcv, pt-msgsnd, pt-poll, pt-select, pt-sigpause, pt-sigsuspend,
	pt-sigwait, pt-sigwaitinfo, and pt-waitid.
	* Versions: Add all the new functions.

	* tst-exit1.c: New file.
	* Makefile (tests): Add tst-exit1.

	* sem_timedwait.c: Minor optimization for more optimal fastpath.

2002-10-08  Ulrich Drepper  <drepper@redhat.com>

	* pt-fcntl.c: Only enable asynchronous cancellation for F_SETLKW.

	* pthread_join.c: Enable asynchronous cancellation around lll_wait_tid
	call.  pthread_join is an official cancellation point.
	* pthread_timedjoin.c: Likewise.

	* pthread_cond_wait.c: Revert order in which internal lock are dropped
	and the condvar's mutex are retrieved.
	* pthread_cond_timedwait.c: Likewise.
	Reported by dice@saros.East.Sun.COM.

2002-10-07  Ulrich Drepper  <drepper@redhat.com>

	* pthreadP.h: Cut out all type definitions and move them...
	* sysdeps/unix/sysv/linux/internaltypes.h: ...here.  New file.
	* pthreadP.h: Include <internaltypes.h>.

	* sysdeps/unix/sysv/linux/i386/lowlevelsem.h (lll_sem_post): Little
	performance tweaks.

	* sem_trywait.c: Shuffle #includes around to get right order.
	* sem_timedwait.c: Likewise.
	* sem_post.c: Likewise.
	* sem_wait.c: Likewise.

	* nptl 0.3 released.

	* Makefile (tests): Add tst-signal3.
	* tst-signal3.c: New file.

2002-10-05  Ulrich Drepper  <drepper@redhat.com>

	* sysdeps/unix/sysv/linux/i386/lowlevelsem.h: Tell the compiler that
	the asms modify the sem object.
	(__lll_sem_timedwait): Now takes struct sem* as first parameter.

	* sysdeps/unix/sysv/linux/i386/bits/semaphore.h (sem_t): Don't expose
	the actual members.
	* pthreadP.h (struct sem): New type.  Actual semaphore type.
	* semaphoreP.h: Include pthreadP.h.
	* sem_getvalue.c: Adjust to sem_t change.
	* sem_init.c: Likewise.
	* sem_open.c: Likewise.
	* sem_post.c: Likewise.
	* sem_timedwait.c: Likewise.
	* sem_trywait.c: Likewise.
	* sem_wait.c: Likewise.

2002-10-04  Ulrich Drepper  <drepper@redhat.com>

	* Makefile (tests): Add tst-basic2, tst-exec1, tst-exec3, tst-exec3.
	* tst-basic2.c: New file.
	* tst-exec1.c: New file.
	* tst-exec2.c: New file.
	* tst-exec3.c: New file.

	* tst-fork1.c: Remove extra */.

	* nptl 0.2 released.  The API for IA-32 is complete.
Diffstat (limited to 'nptl/DESIGN-sem.txt')
-rw-r--r--nptl/DESIGN-sem.txt45
1 files changed, 45 insertions, 0 deletions
diff --git a/nptl/DESIGN-sem.txt b/nptl/DESIGN-sem.txt
new file mode 100644
index 0000000000..d25a1c281d
--- /dev/null
+++ b/nptl/DESIGN-sem.txt
@@ -0,0 +1,45 @@
+Semaphores pseudocode
+==============================
+
+       int sem_wait(sem_t * sem);
+       int sem_trywait(sem_t * sem);
+       int sem_post(sem_t * sem);
+       int sem_getvalue(sem_t * sem, int * sval);
+
+struct sem_t {
+
+   unsigned int count;
+         - current semaphore count, also used as a futex
+}
+
+sem_wait(sem_t *sem)
+{
+  for (;;) {
+
+    if (atomic_decrement_if_positive(sem->count))
+      break;
+
+    futex_wait(&sem->count, 0)
+  }
+}
+
+sem_post(sem_t *sem)
+{
+  n = atomic_increment(sem->count);
+  futex_wake(&sem->count, n);
+}
+
+sem_trywait(sem_t *sem)
+{
+  if (atomic_decrement_if_positive(sem->count)) {
+    return 0;
+  } else {
+    return EAGAIN;
+  }
+}
+
+sem_getvalue(sem_t *sem, int *sval)
+{
+  *sval = sem->count;
+  read_barrier();
+}