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| author | Torvald Riegel <triegel@redhat.com> | 2016-11-30 17:53:11 +0100 |
|---|---|---|
| committer | Torvald Riegel <triegel@redhat.com> | 2016-12-05 16:19:43 +0100 |
| commit | ca6e601a9d4a72b3699cca15bad12ac1716bf49a (patch) | |
| tree | fd761ea31c43377d02f2a097f8030411163d6905 /ChangeLog | |
| parent | 71be79a25f1d9efeafa5c634c4499281e8c313f2 (diff) | |
| download | glibc-ca6e601a9d4a72b3699cca15bad12ac1716bf49a.tar.gz glibc-ca6e601a9d4a72b3699cca15bad12ac1716bf49a.tar.xz glibc-ca6e601a9d4a72b3699cca15bad12ac1716bf49a.zip | |
Use C11-like atomics instead of plain memory accesses in x86 lock elision.
This uses atomic operations to access lock elision metadata that is accessed concurrently (ie, adapt_count fields). The size of the data is less than a word but accessed only with atomic loads and stores; therefore, we add support for shorter-size atomic load and stores too. * include/atomic.h (__atomic_check_size_ls): New. (atomic_load_relaxed, atomic_load_acquire, atomic_store_relaxed, atomic_store_release): Use it. * sysdeps/x86/elide.h (ACCESS_ONCE): Remove. (elision_adapt, ELIDE_LOCK): Use atomics. * sysdeps/unix/sysv/linux/x86/elision-lock.c (__lll_lock_elision): Use atomics and improve code comments. * sysdeps/unix/sysv/linux/x86/elision-trylock.c (__lll_trylock_elision): Likewise.
Diffstat (limited to 'ChangeLog')
| -rw-r--r-- | ChangeLog | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog index 6cbb0a8b98..9c0aaa6e43 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,15 @@ +2016-12-05 Torvald Riegel <triegel@redhat.com> + + * include/atomic.h (__atomic_check_size_ls): New. + (atomic_load_relaxed, atomic_load_acquire, atomic_store_relaxed, + atomic_store_release): Use it. + * sysdeps/x86/elide.h (ACCESS_ONCE): Remove. + (elision_adapt, ELIDE_LOCK): Use atomics. + * sysdeps/unix/sysv/linux/x86/elision-lock.c (__lll_lock_elision): Use + atomics and improve code comments. + * sysdeps/unix/sysv/linux/x86/elision-trylock.c + (__lll_trylock_elision): Likewise. + 2016-12-04 Samuel Thibault <samuel.thibault@ens-lyon.org> * hurd/hurd.h: Cast errno constants to error_t to fix usage in C++ |