Messages in this thread | | | Date | Fri, 18 Mar 2022 15:48:17 -0700 (PDT) | Subject | Re: [PATCH] csky: Move to generic ticket-spinlock | From | Palmer Dabbelt <> |
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On Fri, 18 Mar 2022 01:34:21 PDT (-0700), guoren@kernel.org wrote: > From: Guo Ren <guoren@linux.alibaba.com> > > There is no benefit from custom implementation for ticket-spinlock, > so move to generic ticket-spinlock for easy maintenance. > > Signed-off-by: Guo Ren <guoren@linux.alibaba.com> > Cc: Palmer Dabbelt <palmer@rivosinc.com>
Thanks, one less port to look at ;)
Looks like there were a few comments on the v1, and I wasn't going to target this at the upcoming merge window anyway because I wanted to give the various RISC-V vendors time to test stuff. LMK if you want me to add this to the others, but I was planning on posting a stable tag either way so no big deal on my end.
> --- > arch/csky/include/asm/Kbuild | 2 + > arch/csky/include/asm/spinlock.h | 82 +------------------------- > arch/csky/include/asm/spinlock_types.h | 20 +------ > 3 files changed, 4 insertions(+), 100 deletions(-) > > diff --git a/arch/csky/include/asm/Kbuild b/arch/csky/include/asm/Kbuild > index 904a18a818be..d94434288c31 100644 > --- a/arch/csky/include/asm/Kbuild > +++ b/arch/csky/include/asm/Kbuild > @@ -3,6 +3,8 @@ generic-y += asm-offsets.h > generic-y += extable.h > generic-y += gpio.h > generic-y += kvm_para.h > +generic-y += ticket-lock.h > +generic-y += ticket-lock-types.h > generic-y += qrwlock.h > generic-y += user.h > generic-y += vmlinux.lds.h > diff --git a/arch/csky/include/asm/spinlock.h b/arch/csky/include/asm/spinlock.h > index 69f5aa249c5f..8bc179ba0d8d 100644 > --- a/arch/csky/include/asm/spinlock.h > +++ b/arch/csky/include/asm/spinlock.h > @@ -3,87 +3,7 @@ > #ifndef __ASM_CSKY_SPINLOCK_H > #define __ASM_CSKY_SPINLOCK_H > > -#include <linux/spinlock_types.h> > -#include <asm/barrier.h> > - > -/* > - * Ticket-based spin-locking. > - */ > -static inline void arch_spin_lock(arch_spinlock_t *lock) > -{ > - arch_spinlock_t lockval; > - u32 ticket_next = 1 << TICKET_NEXT; > - u32 *p = &lock->lock; > - u32 tmp; > - > - asm volatile ( > - "1: ldex.w %0, (%2) \n" > - " mov %1, %0 \n" > - " add %0, %3 \n" > - " stex.w %0, (%2) \n" > - " bez %0, 1b \n" > - : "=&r" (tmp), "=&r" (lockval) > - : "r"(p), "r"(ticket_next) > - : "cc"); > - > - while (lockval.tickets.next != lockval.tickets.owner) > - lockval.tickets.owner = READ_ONCE(lock->tickets.owner); > - > - smp_mb(); > -} > - > -static inline int arch_spin_trylock(arch_spinlock_t *lock) > -{ > - u32 tmp, contended, res; > - u32 ticket_next = 1 << TICKET_NEXT; > - u32 *p = &lock->lock; > - > - do { > - asm volatile ( > - " ldex.w %0, (%3) \n" > - " movi %2, 1 \n" > - " rotli %1, %0, 16 \n" > - " cmpne %1, %0 \n" > - " bt 1f \n" > - " movi %2, 0 \n" > - " add %0, %0, %4 \n" > - " stex.w %0, (%3) \n" > - "1: \n" > - : "=&r" (res), "=&r" (tmp), "=&r" (contended) > - : "r"(p), "r"(ticket_next) > - : "cc"); > - } while (!res); > - > - if (!contended) > - smp_mb(); > - > - return !contended; > -} > - > -static inline void arch_spin_unlock(arch_spinlock_t *lock) > -{ > - smp_mb(); > - WRITE_ONCE(lock->tickets.owner, lock->tickets.owner + 1); > -} > - > -static inline int arch_spin_value_unlocked(arch_spinlock_t lock) > -{ > - return lock.tickets.owner == lock.tickets.next; > -} > - > -static inline int arch_spin_is_locked(arch_spinlock_t *lock) > -{ > - return !arch_spin_value_unlocked(READ_ONCE(*lock)); > -} > - > -static inline int arch_spin_is_contended(arch_spinlock_t *lock) > -{ > - struct __raw_tickets tickets = READ_ONCE(lock->tickets); > - > - return (tickets.next - tickets.owner) > 1; > -} > -#define arch_spin_is_contended arch_spin_is_contended > - > +#include <asm/ticket-lock.h> > #include <asm/qrwlock.h> > > #endif /* __ASM_CSKY_SPINLOCK_H */ > diff --git a/arch/csky/include/asm/spinlock_types.h b/arch/csky/include/asm/spinlock_types.h > index db87a12c3827..0bb7f6022a3b 100644 > --- a/arch/csky/include/asm/spinlock_types.h > +++ b/arch/csky/include/asm/spinlock_types.h > @@ -3,25 +3,7 @@ > #ifndef __ASM_CSKY_SPINLOCK_TYPES_H > #define __ASM_CSKY_SPINLOCK_TYPES_H > > -#ifndef __LINUX_SPINLOCK_TYPES_RAW_H > -# error "please don't include this file directly" > -#endif > - > -#define TICKET_NEXT 16 > - > -typedef struct { > - union { > - u32 lock; > - struct __raw_tickets { > - /* little endian */ > - u16 owner; > - u16 next; > - } tickets; > - }; > -} arch_spinlock_t; > - > -#define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } } > - > +#include <asm/ticket-lock-types.h> > #include <asm-generic/qrwlock_types.h> > > #endif /* __ASM_CSKY_SPINLOCK_TYPES_H */
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