search for: xen_init_spinlocks_jump

This is a follow-up of commit cfd8983f03c7b2 ("x86, locking/spinlocks: Remove ticket (spin)lock implementation"). The static_key structure paravirt_ticketlocks_enabled is now removed as it is no longer used. As a result, the init functions kvm_spinlock_init_jump() and xen_init_spinlocks_jump() are also removed. A simple build and boot test was done to verify it. Signed-off-by: Waiman Long <longman at redhat.com> --- v1->v2: - Remove init functions kvm_spinlock_init_jump() and xen_init_spinlocks_jump(). arch/x86/include/asm/spinlock.h | 3 --- arch/x86/kernel/k...

This is a follow-up of commit cfd8983f03c7b2 ("x86, locking/spinlocks: Remove ticket (spin)lock implementation"). The static_key structure paravirt_ticketlocks_enabled is now removed as it is no longer used. As a result, the init functions kvm_spinlock_init_jump() and xen_init_spinlocks_jump() are also removed. A simple build and boot test was done to verify it. Signed-off-by: Waiman Long <longman at redhat.com> --- v1->v2: - Remove init functions kvm_spinlock_init_jump() and xen_init_spinlocks_jump(). arch/x86/include/asm/spinlock.h | 3 --- arch/x86/kernel/k...

...atic_key paravirt_ticketlocks_enabled = STATIC_KEY_INIT_FALSE; -EXPORT_SYMBOL(paravirt_ticketlocks_enabled); diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index e8a9ea7..a822606 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -155,7 +155,6 @@ static __init int xen_init_spinlocks_jump(void) if (!xen_domain()) return 0; - static_key_slow_inc(&paravirt_ticketlocks_enabled); return 0; } early_initcall(xen_init_spinlocks_jump); -- 1.8.3.1

...atic_key paravirt_ticketlocks_enabled = STATIC_KEY_INIT_FALSE; -EXPORT_SYMBOL(paravirt_ticketlocks_enabled); diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index e8a9ea7..a822606 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -155,7 +155,6 @@ static __init int xen_init_spinlocks_jump(void) if (!xen_domain()) return 0; - static_key_slow_inc(&paravirt_ticketlocks_enabled); return 0; } early_initcall(xen_init_spinlocks_jump); -- 1.8.3.1

> diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c > index e8a9ea7..a822606 100644 > --- a/arch/x86/xen/spinlock.c > +++ b/arch/x86/xen/spinlock.c > @@ -155,7 +155,6 @@ static __init int xen_init_spinlocks_jump(void) > if (!xen_domain()) > return 0; > > - static_key_slow_inc(&paravirt_ticketlocks_enabled); > return 0; > } > early_initcall(xen_init_spinlocks_jump); Looks that with this change there is not much left of xen_init_spinlocks_jump() and so it can be removed....

...ile the jump_label init code needs to happend _after_ the jump labels are > - * enabled and before SMP is started. Hence we use pre-SMP initcall level > - * init. We cannot do it in xen_init_spinlocks as that is done before > - * jump labels are activated. > - */ > -static __init int xen_init_spinlocks_jump(void) > -{ > - if (!xen_pvspin) > - return 0; > - > - if (!xen_domain()) > - return 0; > - > - static_key_slow_inc(&paravirt_ticketlocks_enabled); > - return 0; > -} > -early_initcall(xen_init_spinlocks_jump); > - > static __init int xen_parse_nopvspin(...

...t static_key paravirt_spinlocks_enabled = STATIC_KEY_INIT_FALSE; +EXPORT_SYMBOL(paravirt_spinlocks_enabled); diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index 23b45eb..d332ae0 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -293,7 +293,7 @@ static __init int xen_init_spinlocks_jump(void) if (!xen_domain()) return 0; - static_key_slow_inc(&paravirt_ticketlocks_enabled); + static_key_slow_inc(&paravirt_spinlocks_enabled); return 0; } early_initcall(xen_init_spinlocks_jump); -- 1.7.1

...t static_key paravirt_spinlocks_enabled = STATIC_KEY_INIT_FALSE; +EXPORT_SYMBOL(paravirt_spinlocks_enabled); diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index 23b45eb..d332ae0 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -293,7 +293,7 @@ static __init int xen_init_spinlocks_jump(void) if (!xen_domain()) return 0; - static_key_slow_inc(&paravirt_ticketlocks_enabled); + static_key_slow_inc(&paravirt_spinlocks_enabled); return 0; } early_initcall(xen_init_spinlocks_jump); -- 1.7.1

...- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -293,7 +293,7 @@ static __init int xen_init_spinlocks_jum if (!xen_domain()) return 0; - static_key_slow_inc(&paravirt_ticketlocks_enabled); + static_key_slow_inc(&paravirt_spinlocks_enabled); return 0; } early_initcall(xen_init_spinlocks_jump);

Paravirtualized spinlocks produce some overhead even if the kernel is running on bare metal. The main reason are the more complex locking and unlocking functions. Especially unlocking is no longer just one instruction but so complex that it is no longer inlined. This patch series addresses this issue by adding two more pvops functions to reduce the size of the inlined spinlock functions. When

Paravirtualized spinlocks produce some overhead even if the kernel is running on bare metal. The main reason are the more complex locking and unlocking functions. Especially unlocking is no longer just one instruction but so complex that it is no longer inlined. This patch series addresses this issue by adding two more pvops functions to reduce the size of the inlined spinlock functions. When

v4->v5: - Move the optimized 2-task contending code to the generic file to enable more architectures to use it without code duplication. - Address some of the style-related comments by PeterZ. - Allow the use of unfair queue spinlock in a real para-virtualized execution environment. - Add para-virtualization support to the qspinlock code by ensuring that the lock holder and queue

v4->v5: - Move the optimized 2-task contending code to the generic file to enable more architectures to use it without code duplication. - Address some of the style-related comments by PeterZ. - Allow the use of unfair queue spinlock in a real para-virtualized execution environment. - Add para-virtualization support to the qspinlock code by ensuring that the lock holder and queue

v11->v12: - Based on PeterZ's version of the qspinlock patch (https://lkml.org/lkml/2014/6/15/63). - Incorporated many of the review comments from Konrad Wilk and Paolo Bonzini. - The pvqspinlock code is largely from my previous version with PeterZ's way of going from queue tail to head and his idea of using callee saved calls to KVM and XEN codes. v10->v11: - Use a

v11->v12: - Based on PeterZ's version of the qspinlock patch (https://lkml.org/lkml/2014/6/15/63). - Incorporated many of the review comments from Konrad Wilk and Paolo Bonzini. - The pvqspinlock code is largely from my previous version with PeterZ's way of going from queue tail to head and his idea of using callee saved calls to KVM and XEN codes. v10->v11: - Use a

v13->v14: - Patches 1 & 2: Add queue_spin_unlock_wait() to accommodate commit 78bff1c86 from Oleg Nesterov. - Fix the system hang problem when using PV qspinlock in an over-committed guest due to a racing condition in the pv_set_head_in_tail() function. - Increase the MAYHALT_THRESHOLD from 10 to 1024. - Change kick_cpu into a regular function pointer instead of a

v13->v14: - Patches 1 & 2: Add queue_spin_unlock_wait() to accommodate commit 78bff1c86 from Oleg Nesterov. - Fix the system hang problem when using PV qspinlock in an over-committed guest due to a racing condition in the pv_set_head_in_tail() function. - Increase the MAYHALT_THRESHOLD from 10 to 1024. - Change kick_cpu into a regular function pointer instead of a

v5->v6: - Change the optimized 2-task contending code to make it fairer at the expense of a bit of performance. - Add a patch to support unfair queue spinlock for Xen. - Modify the PV qspinlock code to follow what was done in the PV ticketlock. - Add performance data for the unfair lock as well as the PV support code. v4->v5: - Move the optimized 2-task contending code to the

v5->v6: - Change the optimized 2-task contending code to make it fairer at the expense of a bit of performance. - Add a patch to support unfair queue spinlock for Xen. - Modify the PV qspinlock code to follow what was done in the PV ticketlock. - Add performance data for the unfair lock as well as the PV support code. v4->v5: - Move the optimized 2-task contending code to the

v12->v13: - Change patch 9 to generate separate versions of the queue_spin_lock_slowpath functions for bare metal and PV guest. This reduces the performance impact of the PV code on bare metal systems. v11->v12: - Based on PeterZ's version of the qspinlock patch (https://lkml.org/lkml/2014/6/15/63). - Incorporated many of the review comments from Konrad Wilk and Paolo