| Commit message (Expand) | Author | Age | Files | Lines |
|---|
| * | cheap special-case optimization for normal mutexes•••cycle-level benchmark on atom cpu showed typical pthread_mutex_lock
call dropping from ~120 cycles to ~90 cycles with this change. benefit
may vary with compiler options and version, but this optimization is
very cheap to make and should always help some.
| Rich Felker | 2011-03-30 | 1 | -0/+4 |
| * | revert mutex "optimization" that turned out to be worse | Rich Felker | 2011-03-29 | 1 | -1/+1 |
| * | major improvements to cancellation handling•••- there is no longer any risk of spoofing cancellation requests, since
the cancel flag is set in pthread_cancel rather than in the signal
handler.
- cancellation signal is no longer unblocked when running the
cancellation handlers. instead, pthread_create will cause any new
threads created from a cancellation handler to unblock their own
cancellation signal.
- various tweaks in preparation for POSIX timer support.
| Rich Felker | 2011-03-29 | 2 | -6/+13 |
| * | revert some more spin optimizations that turned out to be pessimizations | Rich Felker | 2011-03-28 | 2 | -3/+2 |
| * | fix broken spinlock due to miscompilation•••actually this trick also seems to have made the uncontended case slower.
| Rich Felker | 2011-03-28 | 1 | -1/+1 |
| * | match glibc/lsb cancellation abi on i386•••glibc made the ridiculous choice to use pass-by-register calling
convention for these functions, which is impossible to duplicate
directly on non-gcc compilers. instead, we use ugly asm to wrap and
convert the calling convention. presumably this works with every
compiler anyone could potentially want to use.
| Rich Felker | 2011-03-25 | 6 | -0/+36 |
| * | prepare pthread_spin_unlock for archs that need memory barriers | Rich Felker | 2011-03-24 | 1 | -1/+2 |
| * | optimize contended case for pthread_spin_trylock | Rich Felker | 2011-03-24 | 1 | -1/+2 |
| * | optimize spinlock spin | Rich Felker | 2011-03-24 | 1 | -1/+1 |
| * | overhaul cancellation to fix resource leaks and dangerous behavior with signals•••this commit addresses two issues:
1. a race condition, whereby a cancellation request occurring after a
syscall returned from kernelspace but before the subsequent
CANCELPT_END would cause cancellable resource-allocating syscalls
(like open) to leak resources.
2. signal handlers invoked while the thread was blocked at a
cancellation point behaved as if asynchronous cancellation mode wer in
effect, resulting in potentially dangerous state corruption if a
cancellation request occurs.
the glibc/nptl implementation of threads shares both of these issues.
with this commit, both are fixed. however, cancellation points
encountered in a signal handler will not be acted upon if the signal
was received while the thread was already at a cancellation point.
they will of course be acted upon after the signal handler returns, so
in real-world usage where signal handlers quickly return, it should
not be a problem. it's possible to solve this problem too by having
sigaction() wrap all signal handlers with a function that uses a
pthread_cleanup handler to catch cancellation, patch up the saved
context, and return into the cancellable function that will catch and
act upon the cancellation. however that would be a lot of complexity
for minimal if any benefit...
| Rich Felker | 2011-03-24 | 3 | -10/+21 |
| * | global cleanup to use the new syscall interface | Rich Felker | 2011-03-20 | 4 | -6/+5 |
| * | if returning errno value directly from a syscall, we need to negate it. | Rich Felker | 2011-03-19 | 2 | -2/+2 |
| * | syscall overhaul part two - unify public and internal syscall interface•••with this patch, the syscallN() functions are no longer needed; a
variadic syscall() macro allows syscalls with anywhere from 0 to 6
arguments to be made with a single macro name. also, manually casting
each non-integer argument with (long) is no longer necessary; the
casts are hidden in the macros.
some source files which depended on being able to define the old macro
SYSCALL_RETURNS_ERRNO have been modified to directly use __syscall()
instead of syscall(). references to SYSCALL_SIGSET_SIZE and SYSCALL_LL
have also been changed.
x86_64 has not been tested, and may need a follow-up commit to fix any
minor bugs/oversights.
| Rich Felker | 2011-03-19 | 7 | -15/+9 |
| * | overhaul syscall interface•••this commit shuffles around the location of syscall definitions so
that we can make a syscall() library function with both SYS_* and
__NR_* style syscall names available to user applications, provides
the syscall() library function, and optimizes the code that performs
the actual inline syscalls in the library itself.
previously on i386 when built as PIC (shared library), syscalls were
incurring bus lock (lock prefix) overhead at entry and exit, due to
the way the ebx register was being loaded (xchg instruction with a
memory operand). now the xchg takes place between two registers.
further cleanup to arch/$(ARCH)/syscall.h is planned.
| Rich Felker | 2011-03-19 | 1 | -2/+2 |
| * | implement robust mutexes•••some of this code should be cleaned up, e.g. using macros for some of
the bit flags, masks, etc. nonetheless, the code is believed to be
working and correct at this point.
| Rich Felker | 2011-03-17 | 8 | -10/+78 |
| * | avoid function call to pthread_self in mutex unlock•••if the mutex was previously locked, we can assume pthread_self was
already called at the time of locking, and thus that the thread
pointer is initialized.
| Rich Felker | 2011-03-17 | 1 | -1/+1 |
| * | unify lock and owner fields of mutex structure•••this change is necessary to free up one slot in the mutex structure so
that we can use doubly-linked lists in the implementation of robust
mutexes.
| Rich Felker | 2011-03-17 | 3 | -7/+6 |
| * | optimize contended normal mutex case; add int compare-and-swap atomic | Rich Felker | 2011-03-17 | 1 | -1/+1 |
| * | simplify logic, slightly optimize contended case for non-default mutex types | Rich Felker | 2011-03-16 | 1 | -4/+2 |
| * | correct error returns for error-checking mutexes | Rich Felker | 2011-03-16 | 2 | -2/+6 |
| * | cut out a syscall on thread creation in the case where guard size is 0 | Rich Felker | 2011-03-16 | 1 | -1/+1 |
| * | don't expose EAGAIN, etc. from timed futex wait to caller | Rich Felker | 2011-03-16 | 1 | -1/+4 |
| * | implement flockfile api, rework stdio locking | Rich Felker | 2011-03-12 | 1 | -0/+1 |
| * | implement dummy pthread_attr_[gs]etschedparam functions•••for some reason these functions are not shaded by the PS/TPS option in
POSIX, so presumably they are mandatory, even though the functionality
they offer is optional. for now, provide them in case any programs
depend on their existence, but disallow any priority except the
default.
| Rich Felker | 2011-03-11 | 2 | -0/+14 |
| * | fix pthread_attr_* implementations to match corrected prototypes | Rich Felker | 2011-03-11 | 4 | -4/+4 |
| * | fix failure behavior of sem_open when sem does not exist | Rich Felker | 2011-03-10 | 1 | -1/+5 |
| * | fix some semaphore wait semantics (race condition deadlock and error checking) | Rich Felker | 2011-03-10 | 2 | -1/+7 |
| * | fix sem_open and sem_close to obey posix semantics•••multiple opens of the same named semaphore must return the same
pointer, and only the last close can unmap it. thus the ugly global
state keeping track of mappings. the maximum number of distinct named
semaphores that can be opened is limited sufficiently small that the
linear searches take trivial time, especially compared to the syscall
overhead of these functions.
| Rich Felker | 2011-03-10 | 2 | -33/+80 |
| * | optimize pthread termination in the non-detached case•••we can avoid blocking signals by simply using a flag to mark that the
thread has exited and prevent it from getting counted in the rsyscall
signal-pingpong. this restores the original pthread create/join
throughput from before the sigprocmask call was added.
| Rich Felker | 2011-03-10 | 1 | -4/+15 |
| * | security fix: check that cancel/rsyscall signal was sent by the process itself | Rich Felker | 2011-03-10 | 1 | -0/+3 |
| * | fix error handling for pthread_sigmask•••it must return errno, not -1, and should reject invalud values for how.
| Rich Felker | 2011-03-09 | 1 | -0/+10 |
| * | optimize pthread initialization•••the set_tid_address returns the tid (which is also the pid when called
from the initial thread) so there is no need to make a separate
syscall to get pid/tid.
| Rich Felker | 2011-03-09 | 1 | -2/+2 |
| * | simplify and optimize pthread_mutex_trylock | Rich Felker | 2011-03-08 | 1 | -17/+16 |
| * | rwlock trylock functions were wrongly returning EAGAIN instead of EBUSY | Rich Felker | 2011-03-08 | 2 | -3/+3 |
| * | fix major breakage in pthread_once (it was always deadlocking)•••the issue was a break statement that was breaking only from the
switch, not the enclosing for loop, and a failure to set the final
success state.
| Rich Felker | 2011-03-08 | 1 | -8/+7 |
| * | fix and optimize non-default-type mutex behavior•••problem 1: mutex type from the attribute was being ignored by
pthread_mutex_init, so recursive/errorchecking mutexes were never
being used at all.
problem 2: ownership of recursive mutexes was not being enforced at
unlock time.
| Rich Felker | 2011-03-08 | 3 | -25/+18 |
| * | implement pthread_mutexattr_[gs]etpshared functions | Rich Felker | 2011-03-08 | 2 | -0/+16 |
| * | disallow cpu time clocks as condattr clock values | Rich Felker | 2011-03-08 | 1 | -1/+1 |
| * | fix off-by-one error in sem_(timed)wait (using old sem value instead of new) | Rich Felker | 2011-03-07 | 1 | -1/+1 |
| * | use the selected clock from the condattr for pthread_cond_timedwait | Rich Felker | 2011-03-07 | 2 | -1/+2 |
| * | implement pthread_rwlockattr_* (essentially no-ops) | Rich Felker | 2011-03-07 | 4 | -0/+28 |
| * | implement pthread_condattr_* interfaces•••note that, while the attributes are stored, they are not used in
pthread_cond_init yet.
| Rich Felker | 2011-03-07 | 6 | -0/+45 |
| * | reject invalid attribute settings•••note that this is a pedantic conformance issue and waste of code. it
only affects broken code or code that is probing for conformance.
| Rich Felker | 2011-03-07 | 2 | -0/+2 |
| * | implement barrier attribute functions (essentially no-ops) | Rich Felker | 2011-03-07 | 4 | -0/+27 |
| * | enforce stack size min in pthread_attr_setstacksize | Rich Felker | 2011-03-04 | 1 | -1/+1 |
| * | implement POSIX semaphores | Rich Felker | 2011-03-04 | 10 | -0/+201 |
| * | optimize POSIX TSD for fast pthread_getspecific | Rich Felker | 2011-03-03 | 4 | -9/+14 |
| * | use rt_sigprocmask, not legacy sigprocmask, syscall in pthread exit code | Rich Felker | 2011-02-19 | 1 | -1/+1 |
| * | race condition fix: block all signals before decrementing thread count•••the existence of a (kernelspace) thread must never have observable
effects after the thread count is decremented. if signals are not
blocked, it could end up handling the signal for rsyscall and
contributing towards the count of threads which have changed ids,
causing a thread to be missed. this could lead to one thread retaining
unwanted privilege level.
this change may also address other subtle race conditions in
application code that uses signals.
| Rich Felker | 2011-02-19 | 3 | -22/+2 |
| * | make pthread_exit run dtors for last thread, wait to decrement thread count | Rich Felker | 2011-02-19 | 1 | -3/+3 |
