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...gt; > > > smp_lwsync() get involved in this cleanup? If I understand you > > > > correctly, this cleanup focuses on external API like smp_{r,w,}mb(), > > > > while smp_lwsync() is internal to PPC. > > > > > > > > Regards, > > > > Boqun > > > > > > I think you missed the leading ___ :) > > > > > > > What I mean here was smp_lwsync() was originally internal to PPC, but > > never mind ;-) > > > > > smp_store_release is external and it needs __smp_lwsync as > > &gt...

...gt; > > > smp_lwsync() get involved in this cleanup? If I understand you > > > > correctly, this cleanup focuses on external API like smp_{r,w,}mb(), > > > > while smp_lwsync() is internal to PPC. > > > > > > > > Regards, > > > > Boqun > > > > > > I think you missed the leading ___ :) > > > > > > > What I mean here was smp_lwsync() was originally internal to PPC, but > > never mind ;-) > > > > > smp_store_release is external and it needs __smp_lwsync as > > &gt...

On Tue, Jan 05, 2016 at 10:51:17AM +0200, Michael S. Tsirkin wrote: > On Tue, Jan 05, 2016 at 09:36:55AM +0800, Boqun Feng wrote: > > Hi Michael, > > > > On Thu, Dec 31, 2015 at 09:07:42PM +0200, Michael S. Tsirkin wrote: > > > This defines __smp_xxx barriers for powerpc > > > for use by virtualization. > > > > > > smp_xxx barriers are removed as they are &gt...

On Tue, Jan 05, 2016 at 10:51:17AM +0200, Michael S. Tsirkin wrote: > On Tue, Jan 05, 2016 at 09:36:55AM +0800, Boqun Feng wrote: > > Hi Michael, > > > > On Thu, Dec 31, 2015 at 09:07:42PM +0200, Michael S. Tsirkin wrote: > > > This defines __smp_xxx barriers for powerpc > > > for use by virtualization. > > > > > > smp_xxx barriers are removed as they are &gt...

On Wed, May 25, 2016 at 04:18:08PM +0800, Pan Xinhui wrote: > cmpxchg_release is light-wight than cmpxchg, we can gain a better > performace then. On some arch like ppc, barrier impact the performace > too much. > > Suggested-by: Boqun Feng <boqun.feng at gmail.com> > Signed-off-by: Pan Xinhui <xinhui.pan at linux.vnet.ibm.com> > --- > kernel/locking/qspinlock_paravirt.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qsp...

On Wed, May 25, 2016 at 04:18:08PM +0800, Pan Xinhui wrote: > cmpxchg_release is light-wight than cmpxchg, we can gain a better > performace then. On some arch like ppc, barrier impact the performace > too much. > > Suggested-by: Boqun Feng <boqun.feng at gmail.com> > Signed-off-by: Pan Xinhui <xinhui.pan at linux.vnet.ibm.com> > --- > kernel/locking/qspinlock_paravirt.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/locking/qspinlock_paravirt.h b/kernel/locking/qsp...

...gt; > +config ARCH_USE_QUEUED_SPINLOCKS > + default y > + bool "Enable qspinlock" I think you just enable qspinlock by default for all PPC platforms. I guess you need to put depends on PPC_PSERIES || PPC_POWERNV here to achieve what you mean in you commit message. Regards, Boqun > + help > + Enabling this option will let kernel use qspinlock which is a kind of > + fairlock. It has shown a good performance improvement on x86 and also ppc > + especially in high contention cases. > + > config PPC_SPLPAR > depends on PPC_PSERIES > bool &quo...

...gt; > +config ARCH_USE_QUEUED_SPINLOCKS > + default y > + bool "Enable qspinlock" I think you just enable qspinlock by default for all PPC platforms. I guess you need to put depends on PPC_PSERIES || PPC_POWERNV here to achieve what you mean in you commit message. Regards, Boqun > + help > + Enabling this option will let kernel use qspinlock which is a kind of > + fairlock. It has shown a good performance improvement on x86 and also ppc > + especially in high contention cases. > + > config PPC_SPLPAR > depends on PPC_PSERIES > bool &quo...

On Wed, Jan 06, 2016 at 09:51:52AM +0800, Boqun Feng wrote: > On Tue, Jan 05, 2016 at 06:16:48PM +0200, Michael S. Tsirkin wrote: > [snip] > > > > > Another thing is that smp_lwsync() may have a third user(other than > > > > > smp_load_acquire() and smp_store_release()): > > > > > > > &gt...

On Fri, Nov 25, 2016 at 01:40:44PM +0100, Peter Zijlstra wrote: > #define SINGLE_LOAD(x) \ > {( \ > compiletime_assert_atomic_type(typeof(x)); \ Should be: compiletime_assert_atomic_type(x); > WARN_SINGLE_COPY_ALIGNMENT(&(x)); \ > READ_ONCE(x); \ > }) > > #define SINGLE_STORE(x, v) \ > ({ \ >

On Fri, Nov 25, 2016 at 01:40:44PM +0100, Peter Zijlstra wrote: > #define SINGLE_LOAD(x) \ > {( \ > compiletime_assert_atomic_type(typeof(x)); \ Should be: compiletime_assert_atomic_type(x); > WARN_SINGLE_COPY_ALIGNMENT(&(x)); \ > READ_ONCE(x); \ > }) > > #define SINGLE_STORE(x, v) \ > ({ \ >

change fomr v1: a simplier definition of default vcpu_is_preempted skip mahcine type check on ppc, and add config. remove dedicated macro. add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner. add more comments thanks boqun and Peter's suggestion. This patch set aims to fix lock holder preemption issues. test-case: perf record -a perf bench sched messaging -g 400 -p && perf report 18.09% sched-messaging [kernel.vmlinux] [k] osq_lock 12.28% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner...

change fomr v1: a simplier definition of default vcpu_is_preempted skip mahcine type check on ppc, and add config. remove dedicated macro. add one patch to drop overload of rwsem_spin_on_owner and mutex_spin_on_owner. add more comments thanks boqun and Peter's suggestion. This patch set aims to fix lock holder preemption issues. test-case: perf record -a perf bench sched messaging -g 400 -p && perf report 18.09% sched-messaging [kernel.vmlinux] [k] osq_lock 12.28% sched-messaging [kernel.vmlinux] [k] rwsem_spin_on_owner...

...ticle.gmane.org/gmane.linux.ports.ppc.embedded/89877 I'm OK to change my patch accordingly, but do we really want smp_lwsync() get involved in this cleanup? If I understand you correctly, this cleanup focuses on external API like smp_{r,w,}mb(), while smp_lwsync() is internal to PPC. Regards, Boqun > WRITE_ONCE(*p, v); \ > } while (0) > > -#define smp_load_acquire(p) \ > +#define __smp_load_acquire(p) \ > ({ \ > typeof(*p) ___p1 = READ_ONCE(*p); \ > compiletime_assert_atomic_type(*p); \ > - smp_lwsync(); \ > + __smp_l...

...ticle.gmane.org/gmane.linux.ports.ppc.embedded/89877 I'm OK to change my patch accordingly, but do we really want smp_lwsync() get involved in this cleanup? If I understand you correctly, this cleanup focuses on external API like smp_{r,w,}mb(), while smp_lwsync() is internal to PPC. Regards, Boqun > WRITE_ONCE(*p, v); \ > } while (0) > > -#define smp_load_acquire(p) \ > +#define __smp_load_acquire(p) \ > ({ \ > typeof(*p) ___p1 = READ_ONCE(*p); \ > compiletime_assert_atomic_type(*p); \ > - smp_lwsync(); \ > + __smp_l...

On Tue, Jan 05, 2016 at 05:53:41PM +0800, Boqun Feng wrote: > On Tue, Jan 05, 2016 at 10:51:17AM +0200, Michael S. Tsirkin wrote: > > On Tue, Jan 05, 2016 at 09:36:55AM +0800, Boqun Feng wrote: > > > Hi Michael, > > > > > > On Thu, Dec 31, 2015 at 09:07:42PM +0200, Michael S. Tsirkin wrote: > > > &gt...

...he fact is powerNV are built into same ???^^ support > kernel image with pSeries. So we need return false if we are runnig as > powerNV. The another fact is that lppaca->yiled_count keeps zero on ??^^ yield > powerNV. So we can just skip the machine type. >? > Suggested-by: Boqun Feng <boqun.feng at gmail.com> > Suggested-by: Peter Zijlstra (Intel) <peterz at infradead.org> > Signed-off-by: Pan Xinhui <xinhui.pan at linux.vnet.ibm.com> > --- > ?arch/powerpc/include/asm/spinlock.h | 18 ++++++++++++++++++ > ?1 file changed, 18 insertions(+) &g...

...he fact is powerNV are built into same ???^^ support > kernel image with pSeries. So we need return false if we are runnig as > powerNV. The another fact is that lppaca->yiled_count keeps zero on ??^^ yield > powerNV. So we can just skip the machine type. >? > Suggested-by: Boqun Feng <boqun.feng at gmail.com> > Suggested-by: Peter Zijlstra (Intel) <peterz at infradead.org> > Signed-off-by: Pan Xinhui <xinhui.pan at linux.vnet.ibm.com> > --- > ?arch/powerpc/include/asm/spinlock.h | 18 ++++++++++++++++++ > ?1 file changed, 18 insertions(+) &g...

On Fri, Nov 25, 2016 at 3:56 PM, Boqun Feng <boqun.feng at gmail.com> wrote: > On Fri, Nov 25, 2016 at 01:44:04PM +0100, Peter Zijlstra wrote: >> On Fri, Nov 25, 2016 at 01:40:44PM +0100, Peter Zijlstra wrote: >> > #define SINGLE_LOAD(x) \ >> > {(...

On Fri, Nov 25, 2016 at 3:56 PM, Boqun Feng <boqun.feng at gmail.com> wrote: > On Fri, Nov 25, 2016 at 01:44:04PM +0100, Peter Zijlstra wrote: >> On Fri, Nov 25, 2016 at 01:40:44PM +0100, Peter Zijlstra wrote: >> > #define SINGLE_LOAD(x) \ >> > {(...