glibc/sysdeps/unix
Stefan Liebler dd037fb3df S390: Optimize lock-elision by decrementing adapt_count at unlock.
This patch decrements the adapt_count while unlocking the futex
instead of before aquiring the futex as it is done on power, too.
Furthermore a transaction is only started if the futex is currently free.
This check is done after starting the transaction, too.
If the futex is not free and the transaction nesting depth is one,
we can simply end the started transaction instead of aborting it.
The implementation of this check was faulty as it always ended the
started transaction.  By using the fallback path, the the outermost
transaction was aborted.  Now the outermost transaction is aborted
directly.

This patch also adds some commentary and aligns the code in
elision-trylock.c to the code in elision-lock.c as possible.

ChangeLog:

	* sysdeps/unix/sysv/linux/s390/lowlevellock.h
	(__lll_unlock_elision, lll_unlock_elision): Add adapt_count argument.
	* sysdeps/unix/sysv/linux/s390/elision-lock.c:
	(__lll_lock_elision): Decrement adapt_count while unlocking
	instead of before locking.
	* sysdeps/unix/sysv/linux/s390/elision-trylock.c
	(__lll_trylock_elision): Likewise.
	* sysdeps/unix/sysv/linux/s390/elision-unlock.c:
	(__lll_unlock_elision): Likewise.
2016-12-20 15:12:48 +01:00
..
alpha Do not override objects in libc.a in other static libraries [BZ #20452] 2016-08-17 14:57:01 +02:00
arm Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
bsd Make padding in struct sockaddr_storage explicit [BZ #20111] 2016-05-23 19:43:09 +02:00
i386 Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
inet
mips Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
powerpc Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
sh Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
sysv/linux S390: Optimize lock-elision by decrementing adapt_count at unlock. 2016-12-20 15:12:48 +01:00
x86_64 Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
Implies
Makefile Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
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confstr.h
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grantpt.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
ifreq.c Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
make-syscalls.sh Make shebang interpreter directives consistent 2016-01-07 04:03:21 -05:00
s-proto-cancel.S
s-proto.S
setxid.h
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syscall.S Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
syscalls.list
sysdep.h Add INTERNAL_SYSCALL_CALL 2016-09-26 08:47:13 -07:00