search for: link_and_wait_nod

...avirt callee saved call, which defaults to the actual unlock sequence: "movb $0, (%rdi)" and a NOP. The actual paravirt code comes in 3 parts; - init_node; this initializes the extra data members required for PV state. PV state data is kept 1 cacheline ahead of the regular data. - link_and_wait_node/kick_node; these are paired with the regular MCS queueing and are placed resp. before/after the paired MCS ops. - wait_head/queue_unlock; the interesting part here is finding the head node to kick. Tracking the head is done in two parts, firstly the pv_wait_head will store its cpu number...

...EUE_SPINLOCK enum kvm_contention_stat { TAKEN_SLOW, TAKEN_SLOW_PICKUP, @@ -796,6 +797,51 @@ static void kvm_unlock_kick(struct arch_ } } } +#else /* QUEUE_SPINLOCK */ + +#include <asm-generic/qspinlock.h> + +PV_CALLEE_SAVE_REGS_THUNK(__pv_init_node); +PV_CALLEE_SAVE_REGS_THUNK(__pv_link_and_wait_node); +PV_CALLEE_SAVE_REGS_THUNK(__pv_kick_node); + +PV_CALLEE_SAVE_REGS_THUNK(__pv_wait_head); +PV_CALLEE_SAVE_REGS_THUNK(__pv_queue_unlock); + +void kvm_wait(int *ptr, int val) +{ + unsigned long flags; + + if (in_nmi()) + return; + + /* + * Make sure an interrupt handler can't upset things in...

...ults to the actual unlock sequence: "movb $0, (%rdi)" and a NOP. > > The actual paravirt code comes in 3 parts; > > - init_node; this initializes the extra data members required for PV > state. PV state data is kept 1 cacheline ahead of the regular data. > > - link_and_wait_node/kick_node; these are paired with the regular MCS > queueing and are placed resp. before/after the paired MCS ops. > > - wait_head/queue_unlock; the interesting part here is finding the > head node to kick. > > Tracking the head is done in two parts, firstly the pv_wait_h...

...ults to the actual unlock sequence: "movb $0, (%rdi)" and a NOP. > > The actual paravirt code comes in 3 parts; > > - init_node; this initializes the extra data members required for PV > state. PV state data is kept 1 cacheline ahead of the regular data. > > - link_and_wait_node/kick_node; these are paired with the regular MCS > queueing and are placed resp. before/after the paired MCS ops. > > - wait_head/queue_unlock; the interesting part here is finding the > head node to kick. > > Tracking the head is done in two parts, firstly the pv_wait_h...

Since Waiman seems incapable of doing simple things; here's my take on the paravirt crap. The first few patches are taken from Waiman's latest series, but the virt support is completely new. Its primary aim is to not mess up the native code. I've not stress tested it, but the virt and paravirt (kvm) cases boot on simple smp guests. I've not done Xen, but the patch should be

Since Waiman seems incapable of doing simple things; here's my take on the paravirt crap. The first few patches are taken from Waiman's latest series, but the virt support is completely new. Its primary aim is to not mess up the native code. I've not stress tested it, but the virt and paravirt (kvm) cases boot on simple smp guests. I've not done Xen, but the patch should be

...on inlining, a jump label can be added to the unlock function without adding patch sites all over the kernel. The actual paravirt code comes in 5 parts; - init_node; this initializes the extra data members required for PV state. PV state data is kept 1 cacheline ahead of the regular data. - link_and_wait_node; this replaces the regular MCS queuing code. CPU halting can happen if the wait is too long. - wait_head; this waits until the lock is avialable and the CPU will be halted if the wait is too long. - wait_check; this is called after acquiring the lock to see if the next queue head CPU...

...on inlining, a jump label can be added to the unlock function without adding patch sites all over the kernel. The actual paravirt code comes in 5 parts; - init_node; this initializes the extra data members required for PV state. PV state data is kept 1 cacheline ahead of the regular data. - link_and_wait_node; this replaces the regular MCS queuing code. CPU halting can happen if the wait is too long. - wait_head; this waits until the lock is avialable and the CPU will be halted if the wait is too long. - wait_check; this is called after acquiring the lock to see if the next queue head CPU...

...e, however, the disabling of unlock function inlining does have some slight impact on bare metal performance. The actual paravirt code comes in 5 parts; - init_node; this initializes the extra data members required for PV state. PV state data is kept 1 cacheline ahead of the regular data. - link_and_wait_node; this replaces the regular MCS queuing code. CPU halting can happen if the wait is too long. - wait_head; this waits until the lock is avialable and the CPU will be halted if the wait is too long. - wait_check; this is called after acquiring the lock to see if the next queue head CPU...

...e, however, the disabling of unlock function inlining does have some slight impact on bare metal performance. The actual paravirt code comes in 5 parts; - init_node; this initializes the extra data members required for PV state. PV state data is kept 1 cacheline ahead of the regular data. - link_and_wait_node; this replaces the regular MCS queuing code. CPU halting can happen if the wait is too long. - wait_head; this waits until the lock is avialable and the CPU will be halted if the wait is too long. - wait_check; this is called after acquiring the lock to see if the next queue head CPU...

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

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

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