From 9043442b43b1fddf202591b84702863286700c1a Mon Sep 17 00:00:00 2001 From: Juergen Gross Date: Wed, 6 Sep 2017 19:36:24 +0200 Subject: locking/paravirt: Use new static key for controlling call of virt_spin_lock() There are cases where a guest tries to switch spinlocks to bare metal behavior (e.g. by setting "xen_nopvspin" boot parameter). Today this has the downside of falling back to unfair test and set scheme for qspinlocks due to virt_spin_lock() detecting the virtualized environment. Add a static key controlling whether virt_spin_lock() should be called or not. When running on bare metal set the new key to false. Signed-off-by: Juergen Gross Signed-off-by: Peter Zijlstra (Intel) Acked-by: Waiman Long Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: akataria@vmware.com Cc: boris.ostrovsky@oracle.com Cc: chrisw@sous-sol.org Cc: hpa@zytor.com Cc: jeremy@goop.org Cc: rusty@rustcorp.com.au Cc: virtualization@lists.linux-foundation.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20170906173625.18158-2-jgross@suse.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/smpboot.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/kernel/smpboot.c') diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index ad59edd84de7..361f91674ce5 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -77,6 +77,7 @@ #include #include #include +#include /* Number of siblings per CPU package */ int smp_num_siblings = 1; @@ -1384,6 +1385,7 @@ void __init native_smp_prepare_boot_cpu(void) /* already set me in cpu_online_mask in boot_cpu_init() */ cpumask_set_cpu(me, cpu_callout_mask); cpu_set_state_online(me); + native_pv_lock_init(); } void __init native_smp_cpus_done(unsigned int max_cpus) -- cgit v1.2.1 From ca5d376e17072c1b60c3fee66f3be58ef018952d Mon Sep 17 00:00:00 2001 From: Dou Liyang Date: Sat, 28 Oct 2017 14:06:44 +0800 Subject: x86/paravirt: Set up the virt_spin_lock_key after static keys get initialized Commit: 9043442b43b1 ("locking/paravirt: Use new static key for controlling call of virt_spin_lock()") sets the static virt_spin_lock_key to a value before jump_label_init() has been called, which will result in a WARN(). Reorder the initialization sequence: - Move the native_pv_lock_init() into native_smp_prepare_cpus() - set the value in xen_init_lock_cpu() to avoid calling into the not yet initialized static keys subsystem. Suggested-by: Juergen Gross Reported-by: Juergen Gross Signed-off-by: Dou Liyang Reviewed-by: Juergen Gross Acked-by: Thomas Gleixner Cc: Linus Torvalds Cc: Peter Zijlstra Cc: boris.ostrovsky@oracle.com Cc: bp@suse.de Cc: luto@kernel.org Cc: vkuznets@redhat.com Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1509170804-3813-1-git-send-email-douly.fnst@cn.fujitsu.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/smpboot.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/x86/kernel/smpboot.c') diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 361f91674ce5..198416ddff01 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1358,6 +1358,8 @@ void __init native_smp_prepare_cpus(unsigned int max_cpus) pr_info("CPU0: "); print_cpu_info(&cpu_data(0)); + native_pv_lock_init(); + uv_system_init(); set_mtrr_aps_delayed_init(); @@ -1385,7 +1387,6 @@ void __init native_smp_prepare_boot_cpu(void) /* already set me in cpu_online_mask in boot_cpu_init() */ cpumask_set_cpu(me, cpu_callout_mask); cpu_set_state_online(me); - native_pv_lock_init(); } void __init native_smp_cpus_done(unsigned int max_cpus) -- cgit v1.2.1 From 7a10e2a9190628a4024ea394ce7bd641ae40ffd1 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 6 Nov 2017 16:01:23 +0100 Subject: x86: Use lockdep to assert IRQs are disabled/enabled Use lockdep to check that IRQs are enabled or disabled as expected. This way the sanity check only shows overhead when concurrency correctness debug code is enabled. It also makes no more sense to fix the IRQ flags when a bug is detected as the assertion is now pure config-dependent debugging. And to quote Peter Zijlstra: The whole if !disabled, disable logic is uber paranoid programming, but I don't think we've ever seen that WARN trigger, and if it does (and then burns the kernel) we at least know what happend. Signed-off-by: Frederic Weisbecker Acked-by: Thomas Gleixner Cc: David S . Miller Cc: Lai Jiangshan Cc: Linus Torvalds Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Tejun Heo Link: http://lkml.kernel.org/r/1509980490-4285-8-git-send-email-frederic@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/smpboot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kernel/smpboot.c') diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 198416ddff01..4008b6b9ad72 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1095,7 +1095,7 @@ int native_cpu_up(unsigned int cpu, struct task_struct *tidle) unsigned long flags; int err, ret = 0; - WARN_ON(irqs_disabled()); + lockdep_assert_irqs_enabled(); pr_debug("++++++++++++++++++++=_---CPU UP %u\n", cpu); -- cgit v1.2.1