The need to use libc malloc(3) from some places in libthr always
caused issues. For instance, per-thread key allocation was switched to
use plain mmap(2) to get storage, because some third party mallocs
used keys for implementation of calloc(3).
Even more important, libthr calls calloc(3) during initialization of
pthread mutexes, and jemalloc uses pthread mutexes. Jemalloc provides
some way to both postpone the initialization, and to make
initialization to use specialized allocator, but this is very fragile
and often breaks. See the referenced PR for another example.
Add the small malloc implementation used by rtld, to libthr. Use it in
thr_spec.c and for mutexes initialization. This avoids the issues with
mutual dependencies between malloc and libthr in principle. The
drawback is that some more allocations are not interceptable for
alternate malloc implementations. There should be not too much memory
use from this allocator, and the alternative, direct use of mmap(2) is
obviously worse.
PR: 235211
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D18988
Mainly focus on files that use BSD 3-Clause license.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
Fix regression by r318539. The sysutils/pstack uses library libthread_db to
read information about threads state. The function pt_ta_new makes lookup of
several key symbols including _thread_keytable. But r318539 mades this field
static. It causes silent ignore of libthr library by pstack and as result
sysutils/pstack doesn't output any thread information.
This fix changes this field back to non-static.
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D11738
Fix warnings about the following when WARNS=6 (which I will commit soon):
- casting away const
- no previous 'extern' declaration for non-static variable
- others as explained by #pragmas and comments
- unused parameters
The last is the only functional change.
Reviewed by: kib
MFC after: 3 days
Sponsored by: Dell EMC
Differential Revision: https://reviews.freebsd.org/D10808
to handle per-thread information. Since our pthread_setspecific()
implementation calls calloc(3) to allocate per-thread specific data
storage, things get complicated.
Switch the allocator to use bare mmap(2). There is some loss of the
allocated page, since e.g. on amd64, PTHREAD_KEYS_MAX * sizeof(struct
pthread_specific_elem) is 3K (it actually spans whole page due to
padding), but I believe it is more acceptable than additional code for
specialized allocator().
The alternatives would either to make the specific data array be part of
the struct thread, or use internal bindings to call the libc malloc,
avoiding interposing.
Also do the style pass over the thr_spec.c, esp. simplify the
conditionals nesting by returning early when an error detected.
Remove trivial comments.
Found by: yuri@rawbw.com
PR: 200138
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
fixes a NULL-dereference of curthread when libstdc+ initializes
the exception handling globals on archs we can't use GNU TLS due
to lack of support in binutils 2.15 (i.e. arm and sparc64), yet,
thus making threaded C++ programs compiled with GCC 4.2.1 work
again on these archs.
Reviewed by: davidxu
MFC after: 3 days
1. fast simple type mutex.
2. __thread tls works.
3. asynchronous cancellation works ( using signal ).
4. thread synchronization is fully based on umtx, mainly, condition
variable and other synchronization objects were rewritten by using
umtx directly. those objects can be shared between processes via
shared memory, it has to change ABI which does not happen yet.
5. default stack size is increased to 1M on 32 bits platform, 2M for
64 bits platform.
As the result, some mysql super-smack benchmarks show performance is
improved massivly.
Okayed by: jeff, mtm, rwatson, scottl
_get_curthread(). This is similar to the kernel's curthread. Doing
this saves stack overhead and is more convenient to the programmer.
- Pass the pointer to the newly created thread to _thread_init().
- Remove _get_curthread_slow().
