Release 4.10 arch/x86/xen/spinlock.c
/*
* Split spinlock implementation out into its own file, so it can be
* compiled in a FTRACE-compatible way.
*/
#include <linux/kernel_stat.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
#include <linux/log2.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <asm/paravirt.h>
#include <xen/interface/xen.h>
#include <xen/events.h>
#include "xen-ops.h"
#include "debugfs.h"
static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
static DEFINE_PER_CPU(char *, irq_name);
static bool xen_pvspin = true;
#include <asm/qspinlock.h>
static void xen_qlock_kick(int cpu)
{
int irq = per_cpu(lock_kicker_irq, cpu);
/* Don't kick if the target's kicker interrupt is not initialized. */
if (irq == -1)
return;
xen_send_IPI_one(cpu, XEN_SPIN_UNLOCK_VECTOR);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| ross lagerwall | ross lagerwall | 19 | 54.29% | 1 | 50.00% |
| david vrabel | david vrabel | 16 | 45.71% | 1 | 50.00% |
| Total | 35 | 100.00% | 2 | 100.00% |
/*
* Halt the current CPU & release it back to the host
*/
static void xen_qlock_wait(u8 *byte, u8 val)
{
int irq = __this_cpu_read(lock_kicker_irq);
/* If kicker interrupts not initialized yet, just spin */
if (irq == -1)
return;
/* clear pending */
xen_clear_irq_pending(irq);
barrier();
/*
* We check the byte value after clearing pending IRQ to make sure
* that we won't miss a wakeup event because of the clearing.
*
* The sync_clear_bit() call in xen_clear_irq_pending() is atomic.
* So it is effectively a memory barrier for x86.
*/
if (READ_ONCE(*byte) != val)
return;
/*
* If an interrupt happens here, it will leave the wakeup irq
* pending, which will cause xen_poll_irq() to return
* immediately.
*/
/* Block until irq becomes pending (or perhaps a spurious wakeup) */
xen_poll_irq(irq);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david vrabel | david vrabel | 58 | 100.00% | 1 | 100.00% |
| Total | 58 | 100.00% | 1 | 100.00% |
static irqreturn_t dummy_handler(int irq, void *dev_id)
{
BUG();
return IRQ_HANDLED;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 19 | 100.00% | 1 | 100.00% |
| Total | 19 | 100.00% | 1 | 100.00% |
void xen_init_lock_cpu(int cpu)
{
int irq;
char *name;
if (!xen_pvspin)
return;
WARN(per_cpu(lock_kicker_irq, cpu) >= 0, "spinlock on CPU%d exists on IRQ%d!\n",
cpu, per_cpu(lock_kicker_irq, cpu));
name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
cpu,
dummy_handler,
IRQF_PERCPU|IRQF_NOBALANCING,
name,
NULL);
if (irq >= 0) {
disable_irq(irq); /* make sure it's never delivered */
per_cpu(lock_kicker_irq, cpu) = irq;
per_cpu(irq_name, cpu) = name;
}
printk("cpu %d spinlock event irq %d\n", cpu, irq);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 77 | 66.96% | 1 | 20.00% |
| konrad rzeszutek wilk | konrad rzeszutek wilk | 38 | 33.04% | 4 | 80.00% |
| Total | 115 | 100.00% | 5 | 100.00% |
void xen_uninit_lock_cpu(int cpu)
{
if (!xen_pvspin)
return;
unbind_from_irqhandler(per_cpu(lock_kicker_irq, cpu), NULL);
per_cpu(lock_kicker_irq, cpu) = -1;
kfree(per_cpu(irq_name, cpu));
per_cpu(irq_name, cpu) = NULL;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| konrad rzeszutek wilk | konrad rzeszutek wilk | 35 | 63.64% | 3 | 75.00% |
| alex nixon | alex nixon | 20 | 36.36% | 1 | 25.00% |
| Total | 55 | 100.00% | 4 | 100.00% |
PV_CALLEE_SAVE_REGS_THUNK(xen_vcpu_stolen);
/*
* Our init of PV spinlocks is split in two init functions due to us
* using paravirt patching and jump labels patching and having to do
* all of this before SMP code is invoked.
*
* The paravirt patching needs to be done _before_ the alternative asm code
* is started, otherwise we would not patch the core kernel code.
*/
void __init xen_init_spinlocks(void)
{
if (!xen_pvspin) {
printk(KERN_DEBUG "xen: PV spinlocks disabled\n");
return;
}
printk(KERN_DEBUG "xen: PV spinlocks enabled\n");
__pv_init_lock_hash();
pv_lock_ops.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
pv_lock_ops.queued_spin_unlock = PV_CALLEE_SAVE(__pv_queued_spin_unlock);
pv_lock_ops.wait = xen_qlock_wait;
pv_lock_ops.kick = xen_qlock_kick;
pv_lock_ops.vcpu_is_preempted = PV_CALLEE_SAVE(xen_vcpu_stolen);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| david vrabel | david vrabel | 30 | 44.78% | 1 | 16.67% |
| jeremy fitzhardinge | jeremy fitzhardinge | 22 | 32.84% | 2 | 33.33% |
| juergen gross | juergen gross | 6 | 8.96% | 1 | 16.67% |
| konrad rzeszutek wilk | konrad rzeszutek wilk | 6 | 8.96% | 1 | 16.67% |
| peter zijlstra | peter zijlstra | 3 | 4.48% | 1 | 16.67% |
| Total | 67 | 100.00% | 6 | 100.00% |
/*
* While 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(¶virt_ticketlocks_enabled);
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| konrad rzeszutek wilk | konrad rzeszutek wilk | 35 | 100.00% | 2 | 100.00% |
| Total | 35 | 100.00% | 2 | 100.00% |
early_initcall(xen_init_spinlocks_jump);
static __init int xen_parse_nopvspin(char *arg)
{
xen_pvspin = false;
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 18 | 100.00% | 1 | 100.00% |
| Total | 18 | 100.00% | 1 | 100.00% |
early_param("xen_nopvspin", xen_parse_nopvspin);
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| jeremy fitzhardinge | jeremy fitzhardinge | 171 | 35.26% | 3 | 20.00% |
| david vrabel | david vrabel | 134 | 27.63% | 1 | 6.67% |
| konrad rzeszutek wilk | konrad rzeszutek wilk | 124 | 25.57% | 6 | 40.00% |
| alex nixon | alex nixon | 20 | 4.12% | 1 | 6.67% |
| ross lagerwall | ross lagerwall | 19 | 3.92% | 1 | 6.67% |
| peter zijlstra | peter zijlstra | 8 | 1.65% | 1 | 6.67% |
| juergen gross | juergen gross | 6 | 1.24% | 1 | 6.67% |
| tejun heo | tejun heo | 3 | 0.62% | 1 | 6.67% |
| Total | 485 | 100.00% | 15 | 100.00% |
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