similar to: [PATCH v7 07/11] pvqspinlock, x86: Allow unfair queue spinlock in a XEN guest

On Wed, Mar 19, 2014 at 04:14:05PM -0400, Waiman Long wrote: > This patch adds a XEN init function to activate the unfair queue > spinlock in a XEN guest when the PARAVIRT_UNFAIR_LOCKS kernel config > option is selected. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/xen/setup.c | 19 +++++++++++++++++++ > 1 files changed, 19

On Wed, Mar 19, 2014 at 04:14:05PM -0400, Waiman Long wrote: > This patch adds a XEN init function to activate the unfair queue > spinlock in a XEN guest when the PARAVIRT_UNFAIR_LOCKS kernel config > option is selected. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/xen/setup.c | 19 +++++++++++++++++++ > 1 files changed, 19

This patch adds a XEN init function to activate the unfair queue spinlock in a XEN guest when the PARAVIRT_UNFAIR_LOCKS kernel config option is selected. Signed-off-by: Waiman Long <Waiman.Long at hp.com> --- arch/x86/xen/setup.c | 19 +++++++++++++++++++ 1 files changed, 19 insertions(+), 0 deletions(-) diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 0982233..66bb6f5

Locking is always an issue in a virtualized environment as the virtual CPU that is waiting on a lock may get scheduled out and hence block any progress in lock acquisition even when the lock has been freed. One solution to this problem is to allow unfair lock in a para-virtualized environment. In this case, a new lock acquirer can come and steal the lock if the next-in-line CPU to get the lock is

Locking is always an issue in a virtualized environment as the virtual CPU that is waiting on a lock may get scheduled out and hence block any progress in lock acquisition even when the lock has been freed. One solution to this problem is to allow unfair lock in a para-virtualized environment. In this case, a new lock acquirer can come and steal the lock if the next-in-line CPU to get the lock is

On Wed, Feb 26, 2014 at 10:14:25AM -0500, Waiman Long wrote: > This patch adds a KVM init function to activate the unfair queue > spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config > option is selected. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/kernel/kvm.c | 17 +++++++++++++++++ > 1 files changed, 17 insertions(+),

On Wed, Feb 26, 2014 at 10:14:25AM -0500, Waiman Long wrote: > This patch adds a KVM init function to activate the unfair queue > spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config > option is selected. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/kernel/kvm.c | 17 +++++++++++++++++ > 1 files changed, 17 insertions(+),

This patch adds a KVM init function to activate the unfair queue spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config option is selected. Signed-off-by: Waiman Long <Waiman.Long at hp.com> --- arch/x86/kernel/kvm.c | 17 +++++++++++++++++ 1 files changed, 17 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 713f1b3..a489140

This patch adds a KVM init function to activate the unfair queue spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config option is selected. Signed-off-by: Waiman Long <Waiman.Long at hp.com> --- arch/x86/kernel/kvm.c | 17 +++++++++++++++++ 1 files changed, 17 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c index 713f1b3..a489140

Il 26/02/2014 16:14, Waiman Long ha scritto: > This patch adds a KVM init function to activate the unfair queue > spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config > option is selected. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/kernel/kvm.c | 17 +++++++++++++++++ > 1 files changed, 17 insertions(+), 0 deletions(-)

Il 26/02/2014 16:14, Waiman Long ha scritto: > This patch adds a KVM init function to activate the unfair queue > spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config > option is selected. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/kernel/kvm.c | 17 +++++++++++++++++ > 1 files changed, 17 insertions(+), 0 deletions(-)

On 02/26/2014 08:44 PM, Waiman Long wrote: > This patch adds a KVM init function to activate the unfair queue > spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config > option is selected. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/kernel/kvm.c | 17 +++++++++++++++++ > 1 files changed, 17 insertions(+), 0 deletions(-)

On 02/26/2014 08:44 PM, Waiman Long wrote: > This patch adds a KVM init function to activate the unfair queue > spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config > option is selected. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/kernel/kvm.c | 17 +++++++++++++++++ > 1 files changed, 17 insertions(+), 0 deletions(-)

On Wed, Feb 26, 2014 at 10:14:24AM -0500, Waiman Long wrote: > Locking is always an issue in a virtualized environment as the virtual > CPU that is waiting on a lock may get scheduled out and hence block > any progress in lock acquisition even when the lock has been freed. > > One solution to this problem is to allow unfair lock in a > para-virtualized environment. In this case,

On Wed, Feb 26, 2014 at 10:14:24AM -0500, Waiman Long wrote: > Locking is always an issue in a virtualized environment as the virtual > CPU that is waiting on a lock may get scheduled out and hence block > any progress in lock acquisition even when the lock has been freed. > > One solution to this problem is to allow unfair lock in a > para-virtualized environment. In this case,

Il 19/03/2014 21:14, Waiman Long ha scritto: > This patch adds a KVM init function to activate the unfair queue > spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config > option is selected. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/kernel/kvm.c | 17 +++++++++++++++++ > 1 files changed, 17 insertions(+), 0 deletions(-)

Il 19/03/2014 21:14, Waiman Long ha scritto: > This patch adds a KVM init function to activate the unfair queue > spinlock in a KVM guest when the PARAVIRT_UNFAIR_LOCKS kernel config > option is selected. > > Signed-off-by: Waiman Long <Waiman.Long at hp.com> > --- > arch/x86/kernel/kvm.c | 17 +++++++++++++++++ > 1 files changed, 17 insertions(+), 0 deletions(-)

On 02/26/2014 12:07 PM, Konrad Rzeszutek Wilk wrote: > On Wed, Feb 26, 2014 at 10:14:24AM -0500, Waiman Long wrote: >> Locking is always an issue in a virtualized environment as the virtual >> CPU that is waiting on a lock may get scheduled out and hence block >> any progress in lock acquisition even when the lock has been freed. >> >> One solution to this problem

On Mon, Mar 17, 2014 at 01:44:34PM -0400, Waiman Long wrote: > The PV ticketlock code was designed to handle lock holder preemption by > redirecting CPU resources in a preempted guest to another guest that can > better use it and then return the preempted CPU back sooner. But that's the PV code, not the unfair bit. And your fuller PV thing doesn't need the unfair option.

On Mon, Mar 17, 2014 at 01:44:34PM -0400, Waiman Long wrote: > The PV ticketlock code was designed to handle lock holder preemption by > redirecting CPU resources in a preempted guest to another guest that can > better use it and then return the preempted CPU back sooner. But that's the PV code, not the unfair bit. And your fuller PV thing doesn't need the unfair option.