alistair23-linux/arch/xtensa/include/asm
Davidlohr Bueso 3a6bfbc91d arch, locking: Ciao arch_mutex_cpu_relax()
The arch_mutex_cpu_relax() function, introduced by 34b133f, is
hacky and ugly. It was added a few years ago to address the fact
that common cpu_relax() calls include yielding on s390, and thus
impact the optimistic spinning functionality of mutexes. Nowadays
we use this function well beyond mutexes: rwsem, qrwlock, mcs and
lockref. Since the macro that defines the call is in the mutex header,
any users must include mutex.h and the naming is misleading as well.

This patch (i) renames the call to cpu_relax_lowlatency  ("relax, but
only if you can do it with very low latency") and (ii) defines it in
each arch's asm/processor.h local header, just like for regular cpu_relax
functions. On all archs, except s390, cpu_relax_lowlatency is simply cpu_relax,
and thus we can take it out of mutex.h. While this can seem redundant,
I believe it is a good choice as it allows us to move out arch specific
logic from generic locking primitives and enables future(?) archs to
transparently define it, similarly to System Z.

Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Bharat Bhushan <r65777@freescale.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Deepthi Dharwar <deepthi@linux.vnet.ibm.com>
Cc: Dominik Dingel <dingel@linux.vnet.ibm.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Joe Perches <joe@perches.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Joseph Myers <joseph@codesourcery.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Nicolas Pitre <nico@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Qais Yousef <qais.yousef@imgtec.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>
Cc: Rafael Wysocki <rafael.j.wysocki@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Stratos Karafotis <stratosk@semaphore.gr>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Cc: Waiman Long <Waiman.Long@hp.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: adi-buildroot-devel@lists.sourceforge.net
Cc: linux390@de.ibm.com
Cc: linux-alpha@vger.kernel.org
Cc: linux-am33-list@redhat.com
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-c6x-dev@linux-c6x.org
Cc: linux-cris-kernel@axis.com
Cc: linux-hexagon@vger.kernel.org
Cc: linux-ia64@vger.kernel.org
Cc: linux@lists.openrisc.net
Cc: linux-m32r-ja@ml.linux-m32r.org
Cc: linux-m32r@ml.linux-m32r.org
Cc: linux-m68k@lists.linux-m68k.org
Cc: linux-metag@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: linux-sh@vger.kernel.org
Cc: linux-xtensa@linux-xtensa.org
Cc: sparclinux@vger.kernel.org
Link: http://lkml.kernel.org/r/1404079773.2619.4.camel@buesod1.americas.hpqcorp.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-17 12:32:47 +02:00
..
asm-offsets.h
asmmacro.h
atomic.h arch,xtensa: Convert smp_mb__*() 2014-04-18 14:20:47 +02:00
barrier.h arch,xtensa: Convert smp_mb__*() 2014-04-18 14:20:47 +02:00
bitops.h arch,xtensa: Convert smp_mb__*() 2014-04-18 14:20:47 +02:00
bootparam.h xtensa: split bootparam and kernel meminfo 2014-04-02 01:35:51 +04:00
bugs.h
cache.h
cacheasm.h
cacheflush.h xtensa: add SMP support 2014-01-14 10:19:58 -08:00
checksum.h xtensa: add missing include asm/uaccess.h to checksum.h 2013-02-23 19:23:13 -08:00
cmpxchg.h arch: xtensa: include: asm: compiling issue, need cmpxchg64() defined. 2013-06-05 10:14:21 -07:00
coprocessor.h
current.h
delay.h xtensa: implement ndelay 2014-01-15 00:28:11 +04:00
dma-mapping.h
dma.h
elf.h xtensa: add support for TLS 2013-02-23 19:35:57 -08:00
fb.h
fixmap.h xtensa: add HIGHMEM support 2014-04-06 21:29:21 +04:00
flat.h
ftrace.h ftrace: Make CALLER_ADDRx macros more generic 2014-05-21 03:10:32 -04:00
futex.h xtensa: implement robust futex atomic uaccess ops 2014-01-14 10:19:51 -08:00
gpio.h
highmem.h xtensa: add HIGHMEM support 2014-04-06 21:29:21 +04:00
hw_irq.h
initialize_mmu.h xtensa: remap io area defined in device tree 2014-01-15 00:25:14 +04:00
io.h xtensa: fix warning '"CONFIG_OF" is not defined' 2014-01-19 19:29:13 +04:00
irq.h xtensa: implement CPU hotplug 2014-01-14 10:19:59 -08:00
irqflags.h xtensa: fix arch_irqs_disabled_flags implementation 2013-05-09 01:07:11 -07:00
Kbuild locking/mcs: Allow architecture specific asm files to be used for contended case 2014-02-09 21:18:52 +01:00
mmu.h xtensa: add SMP support 2014-01-14 10:19:58 -08:00
mmu_context.h xtensa: add SMP support 2014-01-14 10:19:58 -08:00
module.h
mutex.h
mxregs.h xtensa: add MX irqchip 2014-01-14 10:19:58 -08:00
nommu_context.h
page.h
param.h
pci-bridge.h
pci.h PCI: Turn pcibios_penalize_isa_irq() into a weak function 2014-05-27 16:23:58 -06:00
perf_event.h xtensa: enable HAVE_PERF_EVENTS 2014-01-15 00:27:03 +04:00
pgalloc.h xtensa: use buddy allocator for PTE table 2013-11-15 09:32:19 +09:00
pgtable.h xtensa: add HIGHMEM support 2014-04-06 21:29:21 +04:00
platform.h xtensa: remove unused platform_init_irq() 2013-06-05 10:14:20 -07:00
processor.h arch, locking: Ciao arch_mutex_cpu_relax() 2014-07-17 12:32:47 +02:00
ptrace.h xtensa: add SMP support 2014-01-14 10:19:58 -08:00
regs.h xtensa: keep a3 and excsave1 on entry to exception handlers 2013-09-06 09:47:41 -07:00
rwsem.h
segment.h
serial.h
shmparam.h
signal.h consolidate kernel-side struct sigaction declarations 2013-02-03 15:09:22 -05:00
smp.h xtensa: implement CPU hotplug 2014-01-14 10:19:59 -08:00
spinlock.h xtensa: fix arch spinlock function names 2014-01-14 10:19:53 -08:00
spinlock_types.h xtensa: fix arch spinlock function names 2014-01-14 10:19:53 -08:00
stacktrace.h xtensa: add stacktrace support 2013-05-09 01:07:10 -07:00
string.h xtensa: fix str[n]cmp return value 2013-02-23 19:22:31 -08:00
switch_to.h
syscall.h xtensa: switch to generic sigaltstack 2013-02-03 18:16:27 -05:00
sysmem.h xtensa: keep sysmem banks ordered in add_sysmem_bank 2014-04-02 01:35:52 +04:00
thread_info.h preempt: Make PREEMPT_ACTIVE generic 2013-11-13 20:21:47 +01:00
timex.h xtensa: add SMP support 2014-01-14 10:19:58 -08:00
tlb.h
tlbflush.h xtensa: optimize local_flush_tlb_kernel_range 2014-04-06 21:29:17 +04:00
traps.h xtensa: introduce spill_registers_kernel macro 2014-01-25 23:20:09 +04:00
types.h
uaccess.h
ucontext.h
unaligned.h
unistd.h consolidate cond_syscall and SYSCALL_ALIAS declarations 2013-03-03 22:55:19 -05:00
user.h
vectors.h xtensa: fix warning '"CONFIG_OF" is not defined' 2014-01-19 19:29:13 +04:00
vga.h