| Message ID | 1475164265-246160-2-git-send-email-borntraeger@de.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
在 2016/9/29 23:51, Christian Borntraeger 写道: > this implements the s390 backend for commit > "kernel/sched: introduce vcpu preempted check interface" > by reworking the existing smp_vcpu_scheduled into > arch_vcpu_is_preempted. We can then also get rid of the > local cpu_is_preempted function by moving the > CIF_ENABLED_WAIT test into arch_vcpu_is_preempted. > > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> > --- hi, Christian thanks for your patch! > arch/s390/include/asm/spinlock.h | 3 +++ > arch/s390/kernel/smp.c | 9 +++++++-- > arch/s390/lib/spinlock.c | 25 ++++++++----------------- > 3 files changed, 18 insertions(+), 19 deletions(-) > > diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h > index 63ebf37..e16e02f 100644 > --- a/arch/s390/include/asm/spinlock.h > +++ b/arch/s390/include/asm/spinlock.h > @@ -21,6 +21,9 @@ _raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new) > return __sync_bool_compare_and_swap(lock, old, new); > } > > +bool arch_vcpu_is_preempted(int cpu); > +#define vcpu_is_preempted arch_vcpu_is_preempted > + > /* > * Simple spin lock operations. There are two variants, one clears IRQ's > * on the local processor, one does not. > diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c > index 7b89a75..4aadd16 100644 > --- a/arch/s390/kernel/smp.c > +++ b/arch/s390/kernel/smp.c > @@ -376,10 +376,15 @@ int smp_find_processor_id(u16 address) > return -1; > } > > -int smp_vcpu_scheduled(int cpu) root@ltcalpine2-lp13:~/linux# git grep -wn smp_vcpu_scheduled arch/s390/ arch/s390/include/asm/smp.h:34:extern int smp_vcpu_scheduled(int cpu); arch/s390/include/asm/smp.h:56:static inline int smp_vcpu_scheduled(int cpu) { return 1; } arch/s390/kernel/smp.c:371:int smp_vcpu_scheduled(int cpu) arch/s390/lib/spinlock.c:44: if (smp_vcpu_scheduled(cpu)) > +bool arch_vcpu_is_preempted(int cpu) > { > - return pcpu_running(pcpu_devices + cpu); > + if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) > + return false; > + if (pcpu_running(pcpu_devices + cpu)) > + return false; I saw smp_vcpu_scheduled() returns true always on !SMP system. maybe we can do somegthing silimar. like below #ifndef CONFIG_SMP static inline bool arch_vcpu_is_preempted(int cpu) { return !test_cpu_flag_of(CIF_ENABLED_WAIT, cpu); } #else ... but I can't help thinking that if this is a!SMP system, maybe we could only #ifndef CONFIG_SMP static inline bool arch_vcpu_is_preempted(int cpu) { return false; } #else ... thanks xinhui > + return true; > } > +EXPORT_SYMBOL(arch_vcpu_is_preempted); > > void smp_yield_cpu(int cpu) > { > diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c > index e5f50a7..e48a48e 100644 > --- a/arch/s390/lib/spinlock.c > +++ b/arch/s390/lib/spinlock.c > @@ -37,15 +37,6 @@ static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old) > asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock)); > } > > -static inline int cpu_is_preempted(int cpu) > -{ > - if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) > - return 0; > - if (smp_vcpu_scheduled(cpu)) > - return 0; > - return 1; > -} > - > void arch_spin_lock_wait(arch_spinlock_t *lp) > { > unsigned int cpu = SPINLOCK_LOCKVAL; > @@ -62,7 +53,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp) > continue; > } > /* First iteration: check if the lock owner is running. */ > - if (first_diag && cpu_is_preempted(~owner)) { > + if (first_diag && arch_vcpu_is_preempted(~owner)) { > smp_yield_cpu(~owner); > first_diag = 0; > continue; > @@ -81,7 +72,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp) > * yield the CPU unconditionally. For LPAR rely on the > * sense running status. > */ > - if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) { > + if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) { > smp_yield_cpu(~owner); > first_diag = 0; > } > @@ -108,7 +99,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) > continue; > } > /* Check if the lock owner is running. */ > - if (first_diag && cpu_is_preempted(~owner)) { > + if (first_diag && arch_vcpu_is_preempted(~owner)) { > smp_yield_cpu(~owner); > first_diag = 0; > continue; > @@ -127,7 +118,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) > * yield the CPU unconditionally. For LPAR rely on the > * sense running status. > */ > - if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) { > + if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) { > smp_yield_cpu(~owner); > first_diag = 0; > } > @@ -165,7 +156,7 @@ void _raw_read_lock_wait(arch_rwlock_t *rw) > owner = 0; > while (1) { > if (count-- <= 0) { > - if (owner && cpu_is_preempted(~owner)) > + if (owner && arch_vcpu_is_preempted(~owner)) > smp_yield_cpu(~owner); > count = spin_retry; > } > @@ -211,7 +202,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev) > owner = 0; > while (1) { > if (count-- <= 0) { > - if (owner && cpu_is_preempted(~owner)) > + if (owner && arch_vcpu_is_preempted(~owner)) > smp_yield_cpu(~owner); > count = spin_retry; > } > @@ -241,7 +232,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw) > owner = 0; > while (1) { > if (count-- <= 0) { > - if (owner && cpu_is_preempted(~owner)) > + if (owner && arch_vcpu_is_preempted(~owner)) > smp_yield_cpu(~owner); > count = spin_retry; > } > @@ -285,7 +276,7 @@ void arch_lock_relax(unsigned int cpu) > { > if (!cpu) > return; > - if (MACHINE_IS_LPAR && !cpu_is_preempted(~cpu)) > + if (MACHINE_IS_LPAR && !arch_vcpu_is_preempted(~cpu)) > return; > smp_yield_cpu(~cpu); > } > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, Sep 30, 2016 at 12:49:52PM +0800, Pan Xinhui wrote: > > > 在 2016/9/29 23:51, Christian Borntraeger 写道: > > this implements the s390 backend for commit > > "kernel/sched: introduce vcpu preempted check interface" > > by reworking the existing smp_vcpu_scheduled into > > arch_vcpu_is_preempted. We can then also get rid of the > > local cpu_is_preempted function by moving the > > CIF_ENABLED_WAIT test into arch_vcpu_is_preempted. > > > > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> > > --- > > hi, Christian > thanks for your patch! > > > arch/s390/include/asm/spinlock.h | 3 +++ > > arch/s390/kernel/smp.c | 9 +++++++-- > > arch/s390/lib/spinlock.c | 25 ++++++++----------------- > > 3 files changed, 18 insertions(+), 19 deletions(-) > > > > diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h > > index 63ebf37..e16e02f 100644 > > --- a/arch/s390/include/asm/spinlock.h > > +++ b/arch/s390/include/asm/spinlock.h > > @@ -21,6 +21,9 @@ _raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new) > > return __sync_bool_compare_and_swap(lock, old, new); > > } > > > > +bool arch_vcpu_is_preempted(int cpu); > > +#define vcpu_is_preempted arch_vcpu_is_preempted > > + > > /* > > * Simple spin lock operations. There are two variants, one clears IRQ's > > * on the local processor, one does not. > > diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c > > index 7b89a75..4aadd16 100644 > > --- a/arch/s390/kernel/smp.c > > +++ b/arch/s390/kernel/smp.c > > @@ -376,10 +376,15 @@ int smp_find_processor_id(u16 address) > > return -1; > > } > > > > -int smp_vcpu_scheduled(int cpu) > root@ltcalpine2-lp13:~/linux# git grep -wn smp_vcpu_scheduled arch/s390/ > arch/s390/include/asm/smp.h:34:extern int smp_vcpu_scheduled(int cpu); > arch/s390/include/asm/smp.h:56:static inline int smp_vcpu_scheduled(int cpu) { return 1; } > arch/s390/kernel/smp.c:371:int smp_vcpu_scheduled(int cpu) > arch/s390/lib/spinlock.c:44: if (smp_vcpu_scheduled(cpu)) > > > +bool arch_vcpu_is_preempted(int cpu) > > { > > - return pcpu_running(pcpu_devices + cpu); > > + if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) > > + return false; > > + if (pcpu_running(pcpu_devices + cpu)) > > + return false; > I saw smp_vcpu_scheduled() returns true always on !SMP system. > > maybe we can do somegthing silimar. like below > > #ifndef CONFIG_SMP > static inline bool arch_vcpu_is_preempted(int cpu) { return !test_cpu_flag_of(CIF_ENABLED_WAIT, cpu); } > #else > ... > > but I can't help thinking that if this is a!SMP system, maybe we could only > #ifndef CONFIG_SMP > static inline bool arch_vcpu_is_preempted(int cpu) { return false; } > #else Why do we need a vcpu_is_preempted() implementation for UP? Where will you use it? Regards, Boqun > ... > > > thanks > xinhui > > > + return true; > > } > > +EXPORT_SYMBOL(arch_vcpu_is_preempted); > > > > void smp_yield_cpu(int cpu) > > { > > diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c > > index e5f50a7..e48a48e 100644 > > --- a/arch/s390/lib/spinlock.c > > +++ b/arch/s390/lib/spinlock.c > > @@ -37,15 +37,6 @@ static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old) > > asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock)); > > } > > > > -static inline int cpu_is_preempted(int cpu) > > -{ > > - if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) > > - return 0; > > - if (smp_vcpu_scheduled(cpu)) > > - return 0; > > - return 1; > > -} > > - > > void arch_spin_lock_wait(arch_spinlock_t *lp) > > { > > unsigned int cpu = SPINLOCK_LOCKVAL; > > @@ -62,7 +53,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp) > > continue; > > } > > /* First iteration: check if the lock owner is running. */ > > - if (first_diag && cpu_is_preempted(~owner)) { > > + if (first_diag && arch_vcpu_is_preempted(~owner)) { > > smp_yield_cpu(~owner); > > first_diag = 0; > > continue; > > @@ -81,7 +72,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp) > > * yield the CPU unconditionally. For LPAR rely on the > > * sense running status. > > */ > > - if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) { > > + if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) { > > smp_yield_cpu(~owner); > > first_diag = 0; > > } > > @@ -108,7 +99,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) > > continue; > > } > > /* Check if the lock owner is running. */ > > - if (first_diag && cpu_is_preempted(~owner)) { > > + if (first_diag && arch_vcpu_is_preempted(~owner)) { > > smp_yield_cpu(~owner); > > first_diag = 0; > > continue; > > @@ -127,7 +118,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) > > * yield the CPU unconditionally. For LPAR rely on the > > * sense running status. > > */ > > - if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) { > > + if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) { > > smp_yield_cpu(~owner); > > first_diag = 0; > > } > > @@ -165,7 +156,7 @@ void _raw_read_lock_wait(arch_rwlock_t *rw) > > owner = 0; > > while (1) { > > if (count-- <= 0) { > > - if (owner && cpu_is_preempted(~owner)) > > + if (owner && arch_vcpu_is_preempted(~owner)) > > smp_yield_cpu(~owner); > > count = spin_retry; > > } > > @@ -211,7 +202,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev) > > owner = 0; > > while (1) { > > if (count-- <= 0) { > > - if (owner && cpu_is_preempted(~owner)) > > + if (owner && arch_vcpu_is_preempted(~owner)) > > smp_yield_cpu(~owner); > > count = spin_retry; > > } > > @@ -241,7 +232,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw) > > owner = 0; > > while (1) { > > if (count-- <= 0) { > > - if (owner && cpu_is_preempted(~owner)) > > + if (owner && arch_vcpu_is_preempted(~owner)) > > smp_yield_cpu(~owner); > > count = spin_retry; > > } > > @@ -285,7 +276,7 @@ void arch_lock_relax(unsigned int cpu) > > { > > if (!cpu) > > return; > > - if (MACHINE_IS_LPAR && !cpu_is_preempted(~cpu)) > > + if (MACHINE_IS_LPAR && !arch_vcpu_is_preempted(~cpu)) > > return; > > smp_yield_cpu(~cpu); > > } > > >
在 2016/9/30 13:52, Boqun Feng 写道: > On Fri, Sep 30, 2016 at 12:49:52PM +0800, Pan Xinhui wrote: >> >> >> 在 2016/9/29 23:51, Christian Borntraeger 写道: >>> this implements the s390 backend for commit >>> "kernel/sched: introduce vcpu preempted check interface" >>> by reworking the existing smp_vcpu_scheduled into >>> arch_vcpu_is_preempted. We can then also get rid of the >>> local cpu_is_preempted function by moving the >>> CIF_ENABLED_WAIT test into arch_vcpu_is_preempted. >>> >>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> >>> --- >> >> hi, Christian >> thanks for your patch! >> >>> arch/s390/include/asm/spinlock.h | 3 +++ >>> arch/s390/kernel/smp.c | 9 +++++++-- >>> arch/s390/lib/spinlock.c | 25 ++++++++----------------- >>> 3 files changed, 18 insertions(+), 19 deletions(-) >>> >>> diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h >>> index 63ebf37..e16e02f 100644 >>> --- a/arch/s390/include/asm/spinlock.h >>> +++ b/arch/s390/include/asm/spinlock.h >>> @@ -21,6 +21,9 @@ _raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new) >>> return __sync_bool_compare_and_swap(lock, old, new); >>> } >>> >>> +bool arch_vcpu_is_preempted(int cpu); >>> +#define vcpu_is_preempted arch_vcpu_is_preempted >>> + >>> /* >>> * Simple spin lock operations. There are two variants, one clears IRQ's >>> * on the local processor, one does not. >>> diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c >>> index 7b89a75..4aadd16 100644 >>> --- a/arch/s390/kernel/smp.c >>> +++ b/arch/s390/kernel/smp.c >>> @@ -376,10 +376,15 @@ int smp_find_processor_id(u16 address) >>> return -1; >>> } >>> >>> -int smp_vcpu_scheduled(int cpu) >> root@ltcalpine2-lp13:~/linux# git grep -wn smp_vcpu_scheduled arch/s390/ >> arch/s390/include/asm/smp.h:34:extern int smp_vcpu_scheduled(int cpu); >> arch/s390/include/asm/smp.h:56:static inline int smp_vcpu_scheduled(int cpu) { return 1; } >> arch/s390/kernel/smp.c:371:int smp_vcpu_scheduled(int cpu) >> arch/s390/lib/spinlock.c:44: if (smp_vcpu_scheduled(cpu)) >> >>> +bool arch_vcpu_is_preempted(int cpu) >>> { >>> - return pcpu_running(pcpu_devices + cpu); >>> + if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) >>> + return false; >>> + if (pcpu_running(pcpu_devices + cpu)) >>> + return false; >> I saw smp_vcpu_scheduled() returns true always on !SMP system. >> >> maybe we can do somegthing silimar. like below >> >> #ifndef CONFIG_SMP >> static inline bool arch_vcpu_is_preempted(int cpu) { return !test_cpu_flag_of(CIF_ENABLED_WAIT, cpu); } >> #else >> ... >> >> but I can't help thinking that if this is a!SMP system, maybe we could only >> #ifndef CONFIG_SMP >> static inline bool arch_vcpu_is_preempted(int cpu) { return false; } >> #else > > Why do we need a vcpu_is_preempted() implementation for UP? Where will > you use it? > yep, I also wonder that :) But there is a definitaion of smp_vcpu_scheduled() for !SMP kernel. So I am a little worried that some code has included this spinlock.h for UP kernel also. Hi, Christian Could you help confirms that your patch works on UP? :) thanks xinhui > Regards, > Boqun > >> ... >> >> >> thanks >> xinhui >> >>> + return true; >>> } >>> +EXPORT_SYMBOL(arch_vcpu_is_preempted); >>> >>> void smp_yield_cpu(int cpu) >>> { >>> diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c >>> index e5f50a7..e48a48e 100644 >>> --- a/arch/s390/lib/spinlock.c >>> +++ b/arch/s390/lib/spinlock.c >>> @@ -37,15 +37,6 @@ static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old) >>> asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock)); >>> } >>> >>> -static inline int cpu_is_preempted(int cpu) >>> -{ >>> - if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) >>> - return 0; >>> - if (smp_vcpu_scheduled(cpu)) >>> - return 0; >>> - return 1; >>> -} >>> - >>> void arch_spin_lock_wait(arch_spinlock_t *lp) >>> { >>> unsigned int cpu = SPINLOCK_LOCKVAL; >>> @@ -62,7 +53,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp) >>> continue; >>> } >>> /* First iteration: check if the lock owner is running. */ >>> - if (first_diag && cpu_is_preempted(~owner)) { >>> + if (first_diag && arch_vcpu_is_preempted(~owner)) { >>> smp_yield_cpu(~owner); >>> first_diag = 0; >>> continue; >>> @@ -81,7 +72,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp) >>> * yield the CPU unconditionally. For LPAR rely on the >>> * sense running status. >>> */ >>> - if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) { >>> + if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) { >>> smp_yield_cpu(~owner); >>> first_diag = 0; >>> } >>> @@ -108,7 +99,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) >>> continue; >>> } >>> /* Check if the lock owner is running. */ >>> - if (first_diag && cpu_is_preempted(~owner)) { >>> + if (first_diag && arch_vcpu_is_preempted(~owner)) { >>> smp_yield_cpu(~owner); >>> first_diag = 0; >>> continue; >>> @@ -127,7 +118,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) >>> * yield the CPU unconditionally. For LPAR rely on the >>> * sense running status. >>> */ >>> - if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) { >>> + if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) { >>> smp_yield_cpu(~owner); >>> first_diag = 0; >>> } >>> @@ -165,7 +156,7 @@ void _raw_read_lock_wait(arch_rwlock_t *rw) >>> owner = 0; >>> while (1) { >>> if (count-- <= 0) { >>> - if (owner && cpu_is_preempted(~owner)) >>> + if (owner && arch_vcpu_is_preempted(~owner)) >>> smp_yield_cpu(~owner); >>> count = spin_retry; >>> } >>> @@ -211,7 +202,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev) >>> owner = 0; >>> while (1) { >>> if (count-- <= 0) { >>> - if (owner && cpu_is_preempted(~owner)) >>> + if (owner && arch_vcpu_is_preempted(~owner)) >>> smp_yield_cpu(~owner); >>> count = spin_retry; >>> } >>> @@ -241,7 +232,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw) >>> owner = 0; >>> while (1) { >>> if (count-- <= 0) { >>> - if (owner && cpu_is_preempted(~owner)) >>> + if (owner && arch_vcpu_is_preempted(~owner)) >>> smp_yield_cpu(~owner); >>> count = spin_retry; >>> } >>> @@ -285,7 +276,7 @@ void arch_lock_relax(unsigned int cpu) >>> { >>> if (!cpu) >>> return; >>> - if (MACHINE_IS_LPAR && !cpu_is_preempted(~cpu)) >>> + if (MACHINE_IS_LPAR && !arch_vcpu_is_preempted(~cpu)) >>> return; >>> smp_yield_cpu(~cpu); >>> } >>> >> -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/30/2016 06:49 AM, Pan Xinhui wrote: > > but I can't help thinking that if this is a!SMP system, maybe we could only > #ifndef CONFIG_SMP > static inline bool arch_vcpu_is_preempted(int cpu) { return false; } > #else Yes, I will add that to v3. Thanks for spotting. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/30/2016 08:35 AM, Pan Xinhui wrote: > > > 在 2016/9/30 13:52, Boqun Feng 写道: >> On Fri, Sep 30, 2016 at 12:49:52PM +0800, Pan Xinhui wrote: >>> >>> >>> 在 2016/9/29 23:51, Christian Borntraeger 写道: >>>> this implements the s390 backend for commit >>>> "kernel/sched: introduce vcpu preempted check interface" >>>> by reworking the existing smp_vcpu_scheduled into >>>> arch_vcpu_is_preempted. We can then also get rid of the >>>> local cpu_is_preempted function by moving the >>>> CIF_ENABLED_WAIT test into arch_vcpu_is_preempted. >>>> >>>> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> >>>> --- >>> >>> hi, Christian >>> thanks for your patch! >>> >>>> arch/s390/include/asm/spinlock.h | 3 +++ >>>> arch/s390/kernel/smp.c | 9 +++++++-- >>>> arch/s390/lib/spinlock.c | 25 ++++++++----------------- >>>> 3 files changed, 18 insertions(+), 19 deletions(-) >>>> >>>> diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h >>>> index 63ebf37..e16e02f 100644 >>>> --- a/arch/s390/include/asm/spinlock.h >>>> +++ b/arch/s390/include/asm/spinlock.h >>>> @@ -21,6 +21,9 @@ _raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new) >>>> return __sync_bool_compare_and_swap(lock, old, new); >>>> } >>>> >>>> +bool arch_vcpu_is_preempted(int cpu); >>>> +#define vcpu_is_preempted arch_vcpu_is_preempted >>>> + >>>> /* >>>> * Simple spin lock operations. There are two variants, one clears IRQ's >>>> * on the local processor, one does not. >>>> diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c >>>> index 7b89a75..4aadd16 100644 >>>> --- a/arch/s390/kernel/smp.c >>>> +++ b/arch/s390/kernel/smp.c >>>> @@ -376,10 +376,15 @@ int smp_find_processor_id(u16 address) >>>> return -1; >>>> } >>>> >>>> -int smp_vcpu_scheduled(int cpu) >>> root@ltcalpine2-lp13:~/linux# git grep -wn smp_vcpu_scheduled arch/s390/ >>> arch/s390/include/asm/smp.h:34:extern int smp_vcpu_scheduled(int cpu); >>> arch/s390/include/asm/smp.h:56:static inline int smp_vcpu_scheduled(int cpu) { return 1; } >>> arch/s390/kernel/smp.c:371:int smp_vcpu_scheduled(int cpu) >>> arch/s390/lib/spinlock.c:44: if (smp_vcpu_scheduled(cpu)) >>> >>>> +bool arch_vcpu_is_preempted(int cpu) >>>> { >>>> - return pcpu_running(pcpu_devices + cpu); >>>> + if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) >>>> + return false; >>>> + if (pcpu_running(pcpu_devices + cpu)) >>>> + return false; >>> I saw smp_vcpu_scheduled() returns true always on !SMP system. >>> >>> maybe we can do somegthing silimar. like below >>> >>> #ifndef CONFIG_SMP >>> static inline bool arch_vcpu_is_preempted(int cpu) { return !test_cpu_flag_of(CIF_ENABLED_WAIT, cpu); } >>> #else >>> ... >>> >>> but I can't help thinking that if this is a!SMP system, maybe we could only >>> #ifndef CONFIG_SMP >>> static inline bool arch_vcpu_is_preempted(int cpu) { return false; } >>> #else >> >> Why do we need a vcpu_is_preempted() implementation for UP? Where will >> you use it? >> > yep, I also wonder that :) > > But there is a definitaion of smp_vcpu_scheduled() for !SMP kernel. > So I am a little worried that some code has included this spinlock.h for UP kernel also. > > Hi, Christian > Could you help confirms that your patch works on UP? :) My patch as is seems to work fine for !SMP. So it looks like the extra define is not necessary and we could simply go with v2 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 09/29/2016 05:51 PM, Christian Borntraeger wrote: > this implements the s390 backend for commit > "kernel/sched: introduce vcpu preempted check interface" > by reworking the existing smp_vcpu_scheduled into > arch_vcpu_is_preempted. We can then also get rid of the > local cpu_is_preempted function by moving the > CIF_ENABLED_WAIT test into arch_vcpu_is_preempted. > > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Martin, Peter, I think we could go with the patch as is. In other words not providing arch_vcpu_is_preempted for !CONFIG_SMP. This will result in compile errors if code does spinning or yielding for non-SMP kernels - which does not make sense to me, so this might actually be a nice indicator. If you prefer the !CONFIG_SMP implementation let me know and I will respin. In any case, Martin if the patch is ok for you, can you ack, so that Peter can take that patch together with Pan Xinhui series? > --- > arch/s390/include/asm/spinlock.h | 3 +++ > arch/s390/kernel/smp.c | 9 +++++++-- > arch/s390/lib/spinlock.c | 25 ++++++++----------------- > 3 files changed, 18 insertions(+), 19 deletions(-) > > diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h > index 63ebf37..e16e02f 100644 > --- a/arch/s390/include/asm/spinlock.h > +++ b/arch/s390/include/asm/spinlock.h > @@ -21,6 +21,9 @@ _raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new) > return __sync_bool_compare_and_swap(lock, old, new); > } > > +bool arch_vcpu_is_preempted(int cpu); > +#define vcpu_is_preempted arch_vcpu_is_preempted > + > /* > * Simple spin lock operations. There are two variants, one clears IRQ's > * on the local processor, one does not. > diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c > index 7b89a75..4aadd16 100644 > --- a/arch/s390/kernel/smp.c > +++ b/arch/s390/kernel/smp.c > @@ -376,10 +376,15 @@ int smp_find_processor_id(u16 address) > return -1; > } > > -int smp_vcpu_scheduled(int cpu) > +bool arch_vcpu_is_preempted(int cpu) > { > - return pcpu_running(pcpu_devices + cpu); > + if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) > + return false; > + if (pcpu_running(pcpu_devices + cpu)) > + return false; > + return true; > } > +EXPORT_SYMBOL(arch_vcpu_is_preempted); > > void smp_yield_cpu(int cpu) > { > diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c > index e5f50a7..e48a48e 100644 > --- a/arch/s390/lib/spinlock.c > +++ b/arch/s390/lib/spinlock.c > @@ -37,15 +37,6 @@ static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old) > asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock)); > } > > -static inline int cpu_is_preempted(int cpu) > -{ > - if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) > - return 0; > - if (smp_vcpu_scheduled(cpu)) > - return 0; > - return 1; > -} > - > void arch_spin_lock_wait(arch_spinlock_t *lp) > { > unsigned int cpu = SPINLOCK_LOCKVAL; > @@ -62,7 +53,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp) > continue; > } > /* First iteration: check if the lock owner is running. */ > - if (first_diag && cpu_is_preempted(~owner)) { > + if (first_diag && arch_vcpu_is_preempted(~owner)) { > smp_yield_cpu(~owner); > first_diag = 0; > continue; > @@ -81,7 +72,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp) > * yield the CPU unconditionally. For LPAR rely on the > * sense running status. > */ > - if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) { > + if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) { > smp_yield_cpu(~owner); > first_diag = 0; > } > @@ -108,7 +99,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) > continue; > } > /* Check if the lock owner is running. */ > - if (first_diag && cpu_is_preempted(~owner)) { > + if (first_diag && arch_vcpu_is_preempted(~owner)) { > smp_yield_cpu(~owner); > first_diag = 0; > continue; > @@ -127,7 +118,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) > * yield the CPU unconditionally. For LPAR rely on the > * sense running status. > */ > - if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) { > + if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) { > smp_yield_cpu(~owner); > first_diag = 0; > } > @@ -165,7 +156,7 @@ void _raw_read_lock_wait(arch_rwlock_t *rw) > owner = 0; > while (1) { > if (count-- <= 0) { > - if (owner && cpu_is_preempted(~owner)) > + if (owner && arch_vcpu_is_preempted(~owner)) > smp_yield_cpu(~owner); > count = spin_retry; > } > @@ -211,7 +202,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev) > owner = 0; > while (1) { > if (count-- <= 0) { > - if (owner && cpu_is_preempted(~owner)) > + if (owner && arch_vcpu_is_preempted(~owner)) > smp_yield_cpu(~owner); > count = spin_retry; > } > @@ -241,7 +232,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw) > owner = 0; > while (1) { > if (count-- <= 0) { > - if (owner && cpu_is_preempted(~owner)) > + if (owner && arch_vcpu_is_preempted(~owner)) > smp_yield_cpu(~owner); > count = spin_retry; > } > @@ -285,7 +276,7 @@ void arch_lock_relax(unsigned int cpu) > { > if (!cpu) > return; > - if (MACHINE_IS_LPAR && !cpu_is_preempted(~cpu)) > + if (MACHINE_IS_LPAR && !arch_vcpu_is_preempted(~cpu)) > return; > smp_yield_cpu(~cpu); > } > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Oct 19, 2016 at 08:56:36AM +0200, Christian Borntraeger wrote: > On 09/29/2016 05:51 PM, Christian Borntraeger wrote: > > this implements the s390 backend for commit > > "kernel/sched: introduce vcpu preempted check interface" > > by reworking the existing smp_vcpu_scheduled into > > arch_vcpu_is_preempted. We can then also get rid of the > > local cpu_is_preempted function by moving the > > CIF_ENABLED_WAIT test into arch_vcpu_is_preempted. > > > > Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> > > > Martin, Peter, > > I think we could go with the patch as is. In other words not providing > arch_vcpu_is_preempted for !CONFIG_SMP. > > This will result in compile errors if code does spinning or yielding for > non-SMP kernels - which does not make sense to me, so this might actually > be a nice indicator. > If you prefer the !CONFIG_SMP implementation let me know and I will respin. ...but I do prefer an implementation for !CONFIG_SMP. I'm tired of fixing silly compile errors that only happen on s390. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h index 63ebf37..e16e02f 100644 --- a/arch/s390/include/asm/spinlock.h +++ b/arch/s390/include/asm/spinlock.h @@ -21,6 +21,9 @@ _raw_compare_and_swap(unsigned int *lock, unsigned int old, unsigned int new) return __sync_bool_compare_and_swap(lock, old, new); } +bool arch_vcpu_is_preempted(int cpu); +#define vcpu_is_preempted arch_vcpu_is_preempted + /* * Simple spin lock operations. There are two variants, one clears IRQ's * on the local processor, one does not. diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 7b89a75..4aadd16 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -376,10 +376,15 @@ int smp_find_processor_id(u16 address) return -1; } -int smp_vcpu_scheduled(int cpu) +bool arch_vcpu_is_preempted(int cpu) { - return pcpu_running(pcpu_devices + cpu); + if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) + return false; + if (pcpu_running(pcpu_devices + cpu)) + return false; + return true; } +EXPORT_SYMBOL(arch_vcpu_is_preempted); void smp_yield_cpu(int cpu) { diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c index e5f50a7..e48a48e 100644 --- a/arch/s390/lib/spinlock.c +++ b/arch/s390/lib/spinlock.c @@ -37,15 +37,6 @@ static inline void _raw_compare_and_delay(unsigned int *lock, unsigned int old) asm(".insn rsy,0xeb0000000022,%0,0,%1" : : "d" (old), "Q" (*lock)); } -static inline int cpu_is_preempted(int cpu) -{ - if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu)) - return 0; - if (smp_vcpu_scheduled(cpu)) - return 0; - return 1; -} - void arch_spin_lock_wait(arch_spinlock_t *lp) { unsigned int cpu = SPINLOCK_LOCKVAL; @@ -62,7 +53,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp) continue; } /* First iteration: check if the lock owner is running. */ - if (first_diag && cpu_is_preempted(~owner)) { + if (first_diag && arch_vcpu_is_preempted(~owner)) { smp_yield_cpu(~owner); first_diag = 0; continue; @@ -81,7 +72,7 @@ void arch_spin_lock_wait(arch_spinlock_t *lp) * yield the CPU unconditionally. For LPAR rely on the * sense running status. */ - if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) { + if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) { smp_yield_cpu(~owner); first_diag = 0; } @@ -108,7 +99,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) continue; } /* Check if the lock owner is running. */ - if (first_diag && cpu_is_preempted(~owner)) { + if (first_diag && arch_vcpu_is_preempted(~owner)) { smp_yield_cpu(~owner); first_diag = 0; continue; @@ -127,7 +118,7 @@ void arch_spin_lock_wait_flags(arch_spinlock_t *lp, unsigned long flags) * yield the CPU unconditionally. For LPAR rely on the * sense running status. */ - if (!MACHINE_IS_LPAR || cpu_is_preempted(~owner)) { + if (!MACHINE_IS_LPAR || arch_vcpu_is_preempted(~owner)) { smp_yield_cpu(~owner); first_diag = 0; } @@ -165,7 +156,7 @@ void _raw_read_lock_wait(arch_rwlock_t *rw) owner = 0; while (1) { if (count-- <= 0) { - if (owner && cpu_is_preempted(~owner)) + if (owner && arch_vcpu_is_preempted(~owner)) smp_yield_cpu(~owner); count = spin_retry; } @@ -211,7 +202,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw, unsigned int prev) owner = 0; while (1) { if (count-- <= 0) { - if (owner && cpu_is_preempted(~owner)) + if (owner && arch_vcpu_is_preempted(~owner)) smp_yield_cpu(~owner); count = spin_retry; } @@ -241,7 +232,7 @@ void _raw_write_lock_wait(arch_rwlock_t *rw) owner = 0; while (1) { if (count-- <= 0) { - if (owner && cpu_is_preempted(~owner)) + if (owner && arch_vcpu_is_preempted(~owner)) smp_yield_cpu(~owner); count = spin_retry; } @@ -285,7 +276,7 @@ void arch_lock_relax(unsigned int cpu) { if (!cpu) return; - if (MACHINE_IS_LPAR && !cpu_is_preempted(~cpu)) + if (MACHINE_IS_LPAR && !arch_vcpu_is_preempted(~cpu)) return; smp_yield_cpu(~cpu); }
this implements the s390 backend for commit "kernel/sched: introduce vcpu preempted check interface" by reworking the existing smp_vcpu_scheduled into arch_vcpu_is_preempted. We can then also get rid of the local cpu_is_preempted function by moving the CIF_ENABLED_WAIT test into arch_vcpu_is_preempted. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> --- arch/s390/include/asm/spinlock.h | 3 +++ arch/s390/kernel/smp.c | 9 +++++++-- arch/s390/lib/spinlock.c | 25 ++++++++----------------- 3 files changed, 18 insertions(+), 19 deletions(-)