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| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2020-07-06 10:21:16 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2020-07-06 10:21:16 +0200 |
| commit | 0c76fc3c2b346dc5401dc055d97d4279632b0fb3 (patch) | |
| tree | 67d7a99ad801c38a137fbb9d08ac54137bb901b9 /NEWS | |
| parent | f9cf87353772ca370b7bb901d86365a564fba49f (diff) | |
| download | glibc-0c76fc3c2b346dc5401dc055d97d4279632b0fb3.tar.gz glibc-0c76fc3c2b346dc5401dc055d97d4279632b0fb3.tar.xz glibc-0c76fc3c2b346dc5401dc055d97d4279632b0fb3.zip | |
Linux: Perform rseq registration at C startup and thread creation
Register rseq TLS for each thread (including main), and unregister for each thread (excluding main). "rseq" stands for Restartable Sequences. See the rseq(2) man page proposed here: https://lkml.org/lkml/2018/9/19/647 Those are based on glibc master branch commit 3ee1e0ec5c. The rseq system call was merged into Linux 4.18. The TLS_STATIC_SURPLUS define is increased to leave additional room for dlopen'd initial-exec TLS, which keeps elf/tst-auditmany working. The increase (76 bytes) is larger than 32 bytes because it has not been increased in quite a while. The cost in terms of additional TLS storage is quite significant, but it will also obscure some initial-exec-related dlopen failures.
Diffstat (limited to 'NEWS')
| -rw-r--r-- | NEWS | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/NEWS b/NEWS index a660fc59a8..a12b9378e7 100644 --- a/NEWS +++ b/NEWS @@ -31,6 +31,16 @@ Major new features: pthread_attr_getsigmask_np have been added. They allow applications to specify the signal mask of a thread created with pthread_create. +* Support for automatically registering threads with the Linux rseq + system call has been added. This system call is implemented starting + from Linux 4.18. The Restartable Sequences ABI accelerates user-space + operations on per-cpu data. It allows user-space to perform updates + on per-cpu data without requiring heavy-weight atomic operations. + Automatically registering threads allows all libraries, including libc, + to make immediate use of the rseq support by using the documented ABI. + The GNU C Library manual has details on integration of Restartable + Sequences. + Deprecated and removed features, and other changes affecting compatibility: * The deprecated <sys/sysctl.h> header and the sysctl function have been |