2
0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-18 02:04:05 +08:00
linux-next/arch
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
..
alpha locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
arc locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
arm locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
arm64 locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
avr32 locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
blackfin locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
c6x locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
cris locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
frv locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
h8300 locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
hexagon locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
ia64 locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
m32r locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
m68k locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
metag locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
microblaze locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
mips locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
mn10300 locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
nios2 locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
openrisc locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
parisc locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
powerpc locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
s390 locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
score locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
sh locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
sparc locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
tile locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
um locking/mutex: Kill arch specific code 2016-10-25 11:31:51 +02:00
unicore32 locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
x86 locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
xtensa locking/core: Introduce cpu_relax_yield() 2016-11-16 10:15:09 +01:00
.gitignore
Kconfig This adds a new gcc plugin named "latent_entropy". It is designed to 2016-10-15 10:03:15 -07:00