a feature that libstdc++ depends on to simulate the behavior of libc's
internal '__isthreaded' variable. One benefit of this is that _libc_once()
is now private to _once_stub.c.
Requested by: kan
with the additional property that it is safe for routines in libc to use
in both single-threaded and multi-threaded processes. Multi-threaded
processes use the pthread_once() implementation from the threading library
while single-threaded processes use a simplified "stub" version internal
to libc. The libc stub-version of pthread_once() now also uses the
simplified "stub" version as well instead of being a nop.
Reviewed by: deischen, Matthew Fleming @ Isilon
Suggested by: alc
MFC after: 1 week
Many operating systems also provide MAP_ANONYMOUS. It's not hard to
support this ourselves, we'd better add it to make it more likely for
applications to work out of the box.
Reviewed by: alc (mman.h)
well-known race condition, which elimination was the reason for the
function appearance in first place. If sigmask supplied as argument to
pselect() enables a signal, the signal might be delivered before thread
called select(2), causing lost wakeup. Reimplement pselect() in kernel,
making change of sigmask and sleep atomic.
Since signal shall be delivered to the usermode, but sigmask restored,
set TDP_OLDMASK and save old mask in td_oldsigmask. The TDP_OLDMASK
should be cleared by ast() in case signal was not gelivered during
syscall execution.
Reviewed by: davidxu
Tested by: pho
MFC after: 1 month
* retry various system calls on EINTR
* retry the rest after a short read (common if there is more than about 1K
of output)
* block SIGCHLD like system(3) does (note that this does not and cannot
work fully in threaded programs, they will need to be careful with wait
functions)
PR: 90580
MFC after: 1 month
one path. When the list is empty (contain only a NULL pointer), return
EINVAL instead of pretending to succeed, which will cause a NULL pointer
deference in a later fts_read() call.
Noticed by: Christoph Mallon (via rdivacky@)
MFC after: 2 weeks
- Tolerate applications that pass a NULL pointer for the buffer and
claim that the capacity of the buffer is nonzero.
- If an application passes in a non-NULL buffer pointer and claims the
buffer has zero capacity, we should free (well, realloc) it
anyway. It could have been obtained from malloc(0), so failing to
free it would be a small memory leak.
MFC After: 2 weeks
Reported by: naddy
PR: ports/138320
the type argument. This is known to fix some pthread_mutexattr_settype()
invocations, especially when it comes to pulseaudio.
Approved by: kib
deischen (threads)
MFC after: 3 days
- F_READAHEAD: specify the amount for sequential access. The amount is
specified in bytes and is rounded up to nearest block size.
- F_RDAHEAD: Darwin compatible version that use 128KB as the sequential
access size.
A third argument of zero disables the read-ahead behavior.
Please note that the read-ahead amount is also constrainted by sysctl
variable, vfs.read_max, which may need to be raised in order to better
utilize this feature.
Thanks Igor Sysoev for proposing the feature and submitting the original
version, and kib@ for his valuable comments.
Submitted by: Igor Sysoev <is rambler-co ru>
Reviewed by: kib@
MFC after: 1 month
a large page size that is greater than malloc(3)'s default chunk size but
less than or equal to 4 MB, then increase the chunk size to match the large
page size.
Most often, using a chunk size that is less than the large page size is not
a problem. However, consider a long-running application that allocates and
frees significant amounts of memory. In particular, it frees enough memory
at times that some of that memory is munmap()ed. Up until the first
munmap(), a 1MB chunk size is just fine; it's not a problem for the virtual
memory system. Two adjacent 1MB chunks that are aligned on a 2MB boundary
will be promoted automatically to a superpage even though they were
allocated at different times. The trouble begins with the munmap(),
releasing a 1MB chunk will trigger the demotion of the containing superpage,
leaving behind a half-used 2MB reservation. Now comes the real problem.
Unfortunately, when the application needs to allocate more memory, and it
recycles the previously munmap()ed address range, the implementation of
mmap() won't be able to reuse the reservation. Basically, the coalescing
rules in the virtual memory system don't allow this new range to combine
with its neighbor. The effect being that superpage promotion will not
reoccur for this range of addresses until both 1MB chunks are freed at some
point in the future.
Reviewed by: jasone
MFC after: 3 weeks
