Add elision tunables

System Internals / glibc - Rogerio Alves [linux.vnet.ibm.com] - 5 December 2017 19:48 EST

This patch adds several new tunables to control the behavior of elision on supported platforms[1]. Since elision now depends on tunables, we should always *compile* with elision enabled, and leave the code disabled, but available for runtime selection. This gives us *much* better compile-time testing of the existing code to avoid bit-rot[2].

Tested on ppc, ppc64, ppc64le, s390x and x86_64.

[1] This part of the patch was initially proposed by Paul Murphy but was "staled" because the framework have changed since the patch was originally proposed:

https://patchwork.sourceware.org/patch/10342/

[2] This part of the patch was inititally proposed as a RFC by Carlos O'Donnell. Make sense to me integrate this on the patch:

https://sourceware.org/ml/libc-alpha/2017-05/msg00335.html

- elf/dl-tunables.list: Add elision parameters.
- manual/tunables.texi: Add entries about elision tunable.
- sysdeps/unix/sysv/linux/powerpc/elision-conf.c: Add callback functions to dynamically enable/disable elision. Add multiple callbacks functions to set elision parameters. Deleted __libc_enable_secure check.
- sysdeps/unix/sysv/linux/s390/elision-conf.c: Likewise.
- sysdeps/unix/sysv/linux/x86/elision-conf.c: Likewise.
- configure: Regenerated.
- configure.ac: Option enable_lock_elision was deleted.
- config.h.in: ENABLE_LOCK_ELISION flag was deleted.
- config.make.in: Remove references to enable_lock_elision.
- manual/install.texi: Elision configure option was removed.
- INSTALL: Regenerated to remove enable_lock_elision.
- nptl/Makefile: Disable elision so it can verify error case for destroying a mutex.
- sysdeps/powerpc/nptl/elide.h: Cleanup ENABLE_LOCK_ELISION check. Deleted macros for the case when ENABLE_LOCK_ELISION was not defined.
- sysdeps/s390/configure: Regenerated.
- sysdeps/s390/configure.ac: Remove references to enable_lock_elision..
- nptl/tst-mutex8.c: Deleted all #ifndef ENABLE_LOCK_ELISION from the test.
- sysdeps/powerpc/powerpc32/sysdep.h: Deleted all ENABLE_LOCK_ELISION checks.
- sysdeps/powerpc/powerpc64/sysdep.h: Likewise.
- sysdeps/powerpc/sysdep.h: Likewise.
- sysdeps/s390/nptl/bits/pthreadtypes-arch.h: Likewise.
- sysdeps/unix/sysv/linux/powerpc/force-elision.h: Likewise.
- sysdeps/unix/sysv/linux/s390/elision-conf.h: Likewise.
- sysdeps/unix/sysv/linux/s390/force-elision.h: Likewise.
- sysdeps/unix/sysv/linux/s390/lowlevellock.h: Likewise.
- sysdeps/unix/sysv/linux/s390/Makefile: Remove references to enable-lock-elision.

07ed18d26a Add elision tunables
ChangeLog | 39 +++++++++++++
INSTALL | 3 -
config.h.in | 3 -
config.make.in | 1 -
configure | 17 ------
configure.ac | 10 ----
elf/dl-tunables.list | 34 +++++++++++
manual/install.texi | 3 -
manual/tunables.texi | 69 +++++++++++++++++++++++
nptl/Makefile | 4 ++
nptl/tst-mutex8.c | 12 +---
sysdeps/powerpc/nptl/elide.h | 9 ---
sysdeps/powerpc/powerpc32/sysdep.h | 2 +-
sysdeps/powerpc/powerpc64/sysdep.h | 2 +-
sysdeps/powerpc/sysdep.h | 4 +-
sysdeps/s390/configure | 2 +-
sysdeps/s390/configure.ac | 2 +-
sysdeps/s390/nptl/bits/pthreadtypes-arch.h | 4 --
sysdeps/unix/sysv/linux/powerpc/elision-conf.c | 75 +++++++++++++++++++++++--
sysdeps/unix/sysv/linux/powerpc/force-elision.h | 2 -
sysdeps/unix/sysv/linux/s390/Makefile | 2 -
sysdeps/unix/sysv/linux/s390/elision-conf.c | 72 ++++++++++++++++++++++--
sysdeps/unix/sysv/linux/s390/elision-conf.h | 2 -
sysdeps/unix/sysv/linux/s390/force-elision.h | 2 -
sysdeps/unix/sysv/linux/s390/lowlevellock.h | 2 -
sysdeps/unix/sysv/linux/x86/elision-conf.c | 74 +++++++++++++++++++++---
26 files changed, 357 insertions(+), 94 deletions(-)

Upstream: sourceware.org


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