search for: slowpath

* Greg KH <gregkh at linuxfoundation.org> wrote: > On Tue, Feb 24, 2015 at 02:54:59PM +0530, Raghavendra K T wrote: > > Paravirt spinlock clears slowpath flag after doing unlock. > > As explained by Linus currently it does: > > prev = *lock; > > add_smp(&lock->tickets.head, TICKET_LOCK_INC); > > > > /* add_smp() is a full mb() */ > > > >...

* Greg KH <gregkh at linuxfoundation.org> wrote: > On Tue, Feb 24, 2015 at 02:54:59PM +0530, Raghavendra K T wrote: > > Paravirt spinlock clears slowpath flag after doing unlock. > > As explained by Linus currently it does: > > prev = *lock; > > add_smp(&lock->tickets.head, TICKET_LOCK_INC); > > > > /* add_smp() is a full mb() */ > > > >...

...Could you add this in the description please: > > > >And by second cacheline we mean the local 'node'. That is the: > >mcs_nodes[0] and mcs_nodes[idx] > > > >Perhaps it might be better then to split this in the header file > >as this is trying to not be a slowpath code - but rather - a > >pre-slow-path-lets-try-if-we can do another cmpxchg in case > >the unlocker has just unlocked itself. > > > >So something like: > > > >diff --git a/include/asm-generic/qspinlock.h b/include/asm-generic/qspinlock.h > >index e8a7ae8.....

...Could you add this in the description please: > > > >And by second cacheline we mean the local 'node'. That is the: > >mcs_nodes[0] and mcs_nodes[idx] > > > >Perhaps it might be better then to split this in the header file > >as this is trying to not be a slowpath code - but rather - a > >pre-slow-path-lets-try-if-we can do another cmpxchg in case > >the unlocker has just unlocked itself. > > > >So something like: > > > >diff --git a/include/asm-generic/qspinlock.h b/include/asm-generic/qspinlock.h > >index e8a7ae8.....

Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))...

Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))...

Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))...

Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))...

Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))...

Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))...

The decision whether the slowpath flag is to be cleared for paravirtualized spinlocks is located in __ticket_check_and_clear_slowpath() today. Move that decision into arch_spin_lock() and add an unlikely attribute to it to avoid calling a function in case the compiler chooses not to inline __ticket_check_and_clear_slowpath() and t...

...;>> And by second cacheline we mean the local 'node'. That is the: > >>>> mcs_nodes[0] and mcs_nodes[idx] > >>>> > >>>> Perhaps it might be better then to split this in the header file > >>>> as this is trying to not be a slowpath code - but rather - a > >>>> pre-slow-path-lets-try-if-we can do another cmpxchg in case > >>>> the unlocker has just unlocked itself. > >>>> > >>>> So something like: > >>>> > >>>> diff --git a/include/...

...;>> And by second cacheline we mean the local 'node'. That is the: > >>>> mcs_nodes[0] and mcs_nodes[idx] > >>>> > >>>> Perhaps it might be better then to split this in the header file > >>>> as this is trying to not be a slowpath code - but rather - a > >>>> pre-slow-path-lets-try-if-we can do another cmpxchg in case > >>>> the unlocker has just unlocked itself. > >>>> > >>>> So something like: > >>>> > >>>> diff --git a/include/...

Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))...

Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG))...

On 02/15/2015 11:25 AM, Raghavendra K T wrote: > Paravirt spinlock clears slowpath flag after doing unlock. > As explained by Linus currently it does: > prev = *lock; > add_smp(&lock->tickets.head, TICKET_LOCK_INC); > > /* add_smp() is a full mb() */ > > if (unlikely(lock->tickets.t...

On 02/15/2015 11:25 AM, Raghavendra K T wrote: > Paravirt spinlock clears slowpath flag after doing unlock. > As explained by Linus currently it does: > prev = *lock; > add_smp(&lock->tickets.head, TICKET_LOCK_INC); > > /* add_smp() is a full mb() */ > > if (unlikely(lock->tickets.t...

On Tue, Feb 24, 2015 at 02:54:59PM +0530, Raghavendra K T wrote: > Paravirt spinlock clears slowpath flag after doing unlock. > As explained by Linus currently it does: > prev = *lock; > add_smp(&lock->tickets.head, TICKET_LOCK_INC); > > /* add_smp() is a full mb() */ > > if (unlikely(lock->tickets.tai...

On Tue, Feb 24, 2015 at 02:54:59PM +0530, Raghavendra K T wrote: > Paravirt spinlock clears slowpath flag after doing unlock. > As explained by Linus currently it does: > prev = *lock; > add_smp(&lock->tickets.head, TICKET_LOCK_INC); > > /* add_smp() is a full mb() */ > > if (unlikely(lock->tickets.tai...

...in V12 - spiltted uapi header patch. - dropped patch 18. - bailout of lock spinning in case of NMI (Gleb) - drop out patch 18 whose benefits are inconclusive (Gleb, Ingo) Changes in V11: - use safe_halt in lock_spinning path to avoid potential problem in case of irq_handlers taking lock in slowpath (Gleb) - add a0 flag for the kick hypercall for future extension (Gleb) - add stubs for missing architecture for kvm_vcpu_schedule() (Gleb) - Change hypercall documentation. - Rebased to 3.11-rc1 Changes in V10: Addressed Konrad''s review comments: - Added break in patch 5 since now w...