Christian Borntraeger 79ab11cdb9 locking/core: Introduce cpu_relax_yield() ... For spinning loops people do often use barrier() or cpu_relax(). For most architectures cpu_relax and barrier are the same, but on some architectures cpu_relax can add some latency. For example on power,sparc64 and arc, cpu_relax can shift the CPU towards other hardware threads in an SMT environment. On s390 cpu_relax does even more, it uses an hypercall to the hypervisor to give up the timeslice. In contrast to the SMT yielding this can result in larger latencies. In some places this latency is unwanted, so another variant "cpu_relax_lowlatency" was introduced. Before this is used in more and more places, lets revert the logic and provide a cpu_relax_yield that can be called in places where yielding is more important than latency. By default this is the same as cpu_relax on all architectures. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Noam Camus <noamc@ezchip.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Cc: linuxppc-dev@lists.ozlabs.org Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1477386195-32736-2-git-send-email-borntraeger@de.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>		2016-11-16 10:15:09 +01:00
..
asm-offsets.h	kbuild: move asm-offsets.h to include/generated	2009-12-12 13:08:14 +01:00
atomic.h	locking/atomic, arch/blackfin: Implement atomic_fetch_{add,sub,and,or,xor}()	2016-06-16 10:48:23 +02:00
barrier.h	blackfin: define __smp_xxx	2016-01-12 20:46:54 +02:00
bfin5xx_spi.h	spi/bfin_spi: drop bits_per_word from client data	2012-03-21 11:00:07 +08:00
bfin_can.h	Blackfin: bfin_can.h: add missing VERSION/VERSION2 MMRs	2010-10-22 16:30:03 -04:00
bfin_dma.h	blackfin: add bf60x to current framework	2012-05-21 14:54:12 +08:00
bfin_pfmon.h	blackfin: license: Change ADI BSD license	2012-05-21 14:54:30 +08:00
bfin_ppi.h	blackfin: add spi/sport3/ppi head file for bf60x	2012-05-21 14:54:18 +08:00
bfin_sdh.h	bf609: rsi: Add bf609 rsi MMR macro and board platform data.	2013-05-07 18:26:18 +08:00
bfin_serial.h	serial: bfin: ctsrts: enfore Kconfig naming convention	2015-05-06 22:26:59 +02:00
bfin_simple_timer.h	bfin: simple_timer: add READ_COUNTER ioctl and add NOIRQ timer mode	2012-07-24 13:39:50 +08:00
bfin_sport3.h	treewide: Fix typos in printk and comment	2013-03-18 14:57:53 +01:00
bfin_sport.h	UAPI: (Scripted) Disintegrate arch/blackfin/include/asm	2012-12-13 13:50:56 +08:00
bfin_twi.h	i2c: bfin-twi: remove unnecessary Blackfin SSYNC from the driver	2014-03-09 08:41:18 +01:00
bfin_watchdog.h	Blackfin: split watchdog definitions into a dedicated header file	2010-03-09 00:30:50 -05:00
bfin-global.h	bfin: add 32M, 16M and 8M uncached DMA region options	2012-07-24 13:39:48 +08:00
bfin-lq035q1.h	Blackfin: extend bfin-lq035q1-fb resources to include PPI mode	2010-03-09 00:30:46 -05:00
bfrom.h	Blackfin arch: Update some inline assembly, tweak some register constraints	2009-01-07 23:14:39 +08:00
bitops.h	arch,blackfin: Convert smp_mb__*()	2014-04-18 11:40:34 +02:00
blackfin.h	blackfin: asm: fix blackfin.h broken	2012-05-21 14:54:08 +08:00
bug.h	Blackfin: change the BUG opcode to an unused 16-bit opcode	2010-05-22 14:19:04 -04:00
cache.h	Blackfin: SMP: fix build breakage in cache.h	2011-01-10 07:18:14 -05:00
cacheflush.h	Blackfin: don't attempt to flush on-chip L1 SRAM regions	2011-05-25 08:13:41 -04:00
cdef_LPBlackfin.h	Blackfin: fix inverted anomaly 05000481 logic	2010-10-25 17:24:00 -04:00
checksum.h	ipv4: Update parameters for csum_tcpudp_magic to their original types	2016-03-13 23:55:13 -04:00
clkdev.h	clk: Add common __clk_get(), __clk_put() implementations	2013-12-04 17:19:44 +01:00
clocks.h	blackfin: bf60x: add clock support	2012-05-21 14:54:13 +08:00
cmpxchg.h	locking/cmpxchg, arch: Remove tas() definitions	2015-12-04 11:39:51 +01:00
context.S	bfin: pm: add deepsleep for bf60x	2012-07-24 13:39:49 +08:00
cplb.h	blackfin: cplb: add support for bf60x	2012-05-21 14:54:16 +08:00
cplbinit.h	Blackfin: mass clean up of copyright/licensing info	2009-10-07 04:36:26 -04:00
cpu.h	blackfin: smp: cleanup smp code	2012-01-09 10:26:15 +08:00
def_LPBlackfin.h	blackfin: Support L1 SRAM parity checking feature on bf60x	2014-01-29 15:12:20 +08:00
delay.h	Blackfin: implement ndelay()	2010-03-09 00:30:50 -05:00
dma-mapping.h	dma-mapping: always provide the dma_map_ops based implementation	2016-01-20 17:09:18 -08:00
dma.h	Revert "blackfin: dma: current count mmr is read only"	2014-06-11 00:13:22 +08:00
dpmc.h	pm: dpmc macro typo fix	2012-07-24 13:39:48 +08:00
early_printk.h	Blackfin: mass clean up of copyright/licensing info	2009-10-07 04:36:26 -04:00
elf.h	default SET_PERSONALITY() in linux/elf.h	2013-02-26 02:46:08 -05:00
entry.h	m68k{nommu}/blackfin : remove old assembler-only flags bit definitions	2010-10-26 16:52:12 -07:00
exec.h	Disintegrate asm/system.h for Blackfin [ver #2]	2012-03-21 11:00:08 +08:00
fixed_code.h	UAPI: (Scripted) Disintegrate arch/blackfin/include/asm	2012-12-13 13:50:56 +08:00
flat.h	Blackfin: mass clean up of copyright/licensing info	2009-10-07 04:36:26 -04:00
ftrace.h	ftrace: Make CALLER_ADDRx macros more generic	2014-05-21 03:10:32 -04:00
gpio.h	blackfin: adi gpio driver and pinctrl driver support	2013-11-15 17:33:42 +08:00
gptimers.h	blackfin: bf60x: enable gptimer clock source	2012-05-21 14:54:20 +08:00
hardirq.h	hardirq: Make hardirq bits generic	2013-11-13 20:21:46 +01:00
io.h	blackfin: Fix build error	2015-06-10 10:19:24 -07:00
ipipe_base.h	Blackfin/ipipe: upgrade to I-pipe mainline	2011-03-18 04:01:10 -04:00
ipipe.h	blackfin: Replace __get_cpu_var uses	2014-08-26 13:45:55 -04:00
irq_handler.h	genirq: Remove irq argument from irq flow handlers	2015-09-16 15:47:51 +02:00
irq.h	pinctrl: Move pint PM storage structure out of blackfin architecture.	2014-02-10 10:13:08 +01:00
irqflags.h	blackfin: mach-common: add sec support for bf60x	2012-05-21 14:54:15 +08:00
Kbuild	locking/mutex: Kill arch specific code	2016-10-25 11:31:51 +02:00
kgdb.h	blackfin: kgdb: skip hardware watchpoint test	2012-03-21 11:00:07 +08:00
l1layout.h	Blackfin: mass clean up of copyright/licensing info	2009-10-07 04:36:26 -04:00
linkage.h	Blackfin: mass clean up of copyright/licensing info	2009-10-07 04:36:26 -04:00
mem_init.h	blackfin: dmc: Improve DDR2 write through in DMC effict controller.	2013-05-07 18:25:59 +08:00
mem_map.h	Blackfin: unify memory map headers	2009-06-22 21:16:07 -04:00
mmu_context.h	blackfin: restore L1 base address and length	2012-03-21 11:00:06 +08:00
mmu.h	Blackfin: mass clean up of copyright/licensing info	2009-10-07 04:36:26 -04:00
module.h	Make most arch asm/module.h files use asm-generic/module.h	2012-09-28 14:31:03 +09:30
nand.h	mtd: Blackfin NFC: fix handling of page sizes	2010-08-05 16:14:38 +01:00
nmi.h	Blackfin: implement nmi_watchdog for SMP on BF561	2010-03-09 00:30:49 -05:00
page_offset.h	Blackfin: mass clean up of copyright/licensing info	2009-10-07 04:36:26 -04:00
page.h	blackfin: add bf60x to current framework	2012-05-21 14:54:12 +08:00
pci.h	PCI: Move pci_dma_* helpers to common code	2016-03-07 10:40:02 -06:00
pda.h	blackfin: SMP: pda: "next" field of blackfin_pda only used in SMP kernel	2012-05-21 14:54:36 +08:00
perf_event.h	Blackfin: initial perf_event support	2011-05-25 08:24:09 -04:00
pgtable.h	blackfin: define dummy pgprot_writecombine for !MMU	2016-03-15 16:55:16 -07:00
pm.h	blackfin: fix build after add bf60x mach/pm.h	2012-05-21 14:55:07 +08:00
portmux.h	blackfin: portmux: cleanup head file	2014-04-12 08:46:32 +08:00
processor.h	locking/core: Introduce cpu_relax_yield()	2016-11-16 10:15:09 +01:00
pseudo_instructions.h	Blackfin: add support for the DBG (debug output) pseudo insn	2010-05-22 14:19:05 -04:00
ptrace.h	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal	2012-12-20 18:05:28 -08:00
reboot.h	Blackfin arch: Fix bug - Run "reboot" hangs bf518-ezbrd	2009-02-04 16:49:45 +08:00
rwlock.h	Blackfin arch: SMP supporting patchset: Blackfin header files and machine common code	2009-01-07 23:14:39 +08:00
scb.h	blackfin: scb: Add system crossbar init code.	2013-09-13 10:42:27 +08:00
sections.h	Blackfin: convert unicode space gremlins	2011-07-23 01:18:23 -04:00
segment.h	Blackfin: mass clean up of copyright/licensing info	2009-10-07 04:36:26 -04:00
smp.h	blackfin: smp: adapt to generic smp helpers	2012-09-07 17:54:56 +08:00
spinlock_types.h	locking: Convert raw_rwlock to arch_rwlock	2009-12-14 23:55:32 +01:00
spinlock.h	locking/spinlock, arch: Update and fix spin_unlock_wait() implementations	2016-06-14 11:55:15 +02:00
string.h	Blackfin: move string functions to normal lib/ assembly	2010-05-22 14:19:09 -04:00
switch_to.h	Disintegrate asm/system.h for Blackfin [ver #2]	2012-03-21 11:00:08 +08:00
syscall.h	Blackfin: initial tracehook support	2010-03-09 00:30:51 -05:00
thread_info.h	blackfin: Remove exec_domain usage	2015-04-12 20:58:24 +02:00
time.h	Blackfin: add support for cpufreq on SMP systems	2010-03-09 00:30:50 -05:00
timex.h	Blackfin arch: make sure cycles is marked as volatile so gcc doesnt reorder on us	2008-10-16 23:55:41 +08:00
tlb.h	Blackfin: mass clean up of copyright/licensing info	2009-10-07 04:36:26 -04:00
tlbflush.h	Blackfin: SMP: add flush_tlb_kernel_range stub	2010-05-21 09:40:20 -04:00
trace.h	Blackfin: make hardware trace output a little more useful	2010-05-21 09:40:19 -04:00
traps.h	bf60x: Add double fault, hardware error and NMI SEC handler	2012-07-24 13:39:52 +08:00
uaccess.h	blackfin: no access_ok() for __copy_{to,from}_user()	2016-09-15 19:51:57 -04:00
unistd.h	sys_sgetmask/sys_ssetmask: add CONFIG_SGETMASK_SYSCALL	2014-06-04 16:54:14 -07:00