[OpenRISC] [PATCH v5 0/7] riscv: Add qspinlock/qrwlock

guoren
2021-03-28T06:30:21Z

Current riscv is still using baby spinlock implementation. It'll cause
fairness and cache line bouncing problems. Many people are involved
and pay the efforts to improve it:

- The first version of patch was made in 2019.1:
https://lore.kernel.org/linux-riscv/20190211043829.30096-1-michaeljclark at mac.com/#r

- The second version was made in 2020.11:
https://lore.kernel.org/linux-riscv/1606225437-22948-2-git-send-email-guoren at kernel.org/

- A good discussion at Platform HSC.2021-03-08:
https://drive.google.com/drive/folders/1ooqdnIsYx7XKor5O1XTtM6D1CHp4hc0p

Hope your comments and Tested-by or Co-developed-by or Reviewed-by ...

Let's kick the qspinlock into riscv right now (Also for the
architecture which hasn't xchg16 atomic instruction.)

Change V5:
- Fixup #endif comment typo by Waiman
- Remove cmpxchg coding convention patches which will get into a
separate patchset later by Arnd's advice
- Try to involve more architectures in the discussion

Change V4:
- Remove custom sub-word xchg implementation
- Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32 in locking/qspinlock

Change V3:
- Coding convention by Peter Zijlstra's advices

Change V2:
- Coding convention in cmpxchg.h
- Re-implement short xchg
- Remove char & cmpxchg implementations

Guo Ren (6):
locking/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32
csky: Convert custom spinlock/rwlock to generic qspinlock/qrwlock
powerpc/qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32
openrisc: qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32
sparc: qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32
xtensa: qspinlock: Add ARCH_USE_QUEUED_SPINLOCKS_XCHG32

Michael Clark (1):
riscv: Convert custom spinlock/rwlock to generic qspinlock/qrwlock

arch/csky/Kconfig | 2 +
arch/csky/include/asm/Kbuild | 2 +
arch/csky/include/asm/spinlock.h | 82 +--------------
arch/csky/include/asm/spinlock_types.h | 16 +--
arch/openrisc/Kconfig | 1 +
arch/powerpc/Kconfig | 1 +
arch/riscv/Kconfig | 3 +
arch/riscv/include/asm/Kbuild | 3 +
arch/riscv/include/asm/spinlock.h | 126 +-----------------------
arch/riscv/include/asm/spinlock_types.h | 15 +--
arch/sparc/Kconfig | 1 +
arch/xtensa/Kconfig | 1 +
kernel/Kconfig.locks | 3 +
kernel/locking/qspinlock.c | 46 +++++----
14 files changed, 49 insertions(+), 253 deletions(-)

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2.17.1