Commit-ID: de7689cf8f3820b34088da3b22ce1a548dda2fc5 Gitweb: http://git.kernel.org/tip/de7689cf8f3820b34088da3b22ce1a548dda2fc5 Author: Juergen Gross <jgross@xxxxxxxx> AuthorDate: Wed, 2 Nov 2016 05:08:37 -0400 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Tue, 22 Nov 2016 12:48:09 +0100 x86/xen: Support the vCPU preemption check Support the vcpu_is_preempted() functionality under Xen. This will enhance lock performance on overcommitted hosts (more runnable vCPUs than physical CPUs in the system) as doing busy waits for preempted vCPUs will hurt system performance far worse than early yielding. A quick test (4 vCPUs on 1 physical CPU doing a parallel build job with "make -j 8") reduced system time by about 5% with this patch. Signed-off-by: Juergen Gross <jgross@xxxxxxxx> Signed-off-by: Pan Xinhui <xinhui.pan@xxxxxxxxxxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: David.Laight@xxxxxxxxxx Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: benh@xxxxxxxxxxxxxxxxxxx Cc: boqun.feng@xxxxxxxxx Cc: borntraeger@xxxxxxxxxx Cc: bsingharora@xxxxxxxxx Cc: dave@xxxxxxxxxxxx Cc: kernellwp@xxxxxxxxx Cc: konrad.wilk@xxxxxxxxxx Cc: linuxppc-dev@xxxxxxxxxxxxxxxx Cc: mpe@xxxxxxxxxxxxxx Cc: paulmck@xxxxxxxxxxxxxxxxxx Cc: paulus@xxxxxxxxx Cc: pbonzini@xxxxxxxxxx Cc: rkrcmar@xxxxxxxxxx Cc: virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx Cc: will.deacon@xxxxxxx Cc: xen-devel-request@xxxxxxxxxxxxxxxxxxxx Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx Link: http://lkml.kernel.org/r/1478077718-37424-11-git-send-email-xinhui.pan@xxxxxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/xen/spinlock.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index 3d6e006..74756bb 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -114,7 +114,6 @@ void xen_uninit_lock_cpu(int cpu) per_cpu(irq_name, cpu) = NULL; } - /* * 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 @@ -137,6 +136,8 @@ void __init xen_init_spinlocks(void) 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 = xen_vcpu_stolen; } /* -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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