Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030885AbcCQNfw (ORCPT ); Thu, 17 Mar 2016 09:35:52 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:33385 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030450AbcCQNft (ORCPT ); Thu, 17 Mar 2016 09:35:49 -0400 From: Boris Ostrovsky To: david.vrabel@citrix.com, konrad.wilk@oracle.com, tglx@linutronix.de Cc: x86@kernel.org, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, Boris Ostrovsky Subject: [PATCH 1/2] xen/x86: Move irq allocation from Xen smp_op.cpu_up() Date: Thu, 17 Mar 2016 09:33:32 -0400 Message-Id: <1458221613-21563-2-git-send-email-boris.ostrovsky@oracle.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1458221613-21563-1-git-send-email-boris.ostrovsky@oracle.com> References: <1458221613-21563-1-git-send-email-boris.ostrovsky@oracle.com> X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6708 Lines: 219 Commit ce0d3c0a6fb1 ("genirq: Revert sparse irq locking around __cpu_up() and move it to x86 for now") reverted irq locking introduced by commit a89941816726 ("hotplug: Prevent alloc/free of irq descriptors during cpu up/down") because of Xen allocating irqs in both of its cpu_up ops. We can move those allocations into CPU notifiers so that original patch can be reinstated. Signed-off-by: Boris Ostrovsky --- arch/x86/xen/enlighten.c | 53 ++++++++++++++++++++++++++++++++++++++------- arch/x86/xen/smp.c | 45 +------------------------------------- arch/x86/xen/smp.h | 3 ++ 3 files changed, 49 insertions(+), 52 deletions(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 2c26108..d1a86db 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -137,6 +137,8 @@ RESERVE_BRK(shared_info_page_brk, PAGE_SIZE); __read_mostly int xen_have_vector_callback; EXPORT_SYMBOL_GPL(xen_have_vector_callback); +static struct notifier_block xen_cpu_notifier; + /* * Point at some empty memory to start with. We map the real shared_info * page as soon as fixmap is up and running. @@ -1596,6 +1598,7 @@ asmlinkage __visible void __init xen_start_kernel(void) xen_initial_gdt = &per_cpu(gdt_page, 0); xen_smp_init(); + register_cpu_notifier(&xen_cpu_notifier); #ifdef CONFIG_ACPI_NUMA /* @@ -1783,17 +1786,49 @@ static void __init init_hvm_pv_info(void) xen_domain_type = XEN_HVM_DOMAIN; } -static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action, - void *hcpu) +static int xen_cpu_notify(struct notifier_block *self, unsigned long action, + void *hcpu) { int cpu = (long)hcpu; + int rc; + switch (action) { case CPU_UP_PREPARE: - xen_vcpu_setup(cpu); - if (xen_have_vector_callback) { - if (xen_feature(XENFEAT_hvm_safe_pvclock)) - xen_setup_timer(cpu); + if (xen_hvm_domain()) { + /* + * This can happen if CPU was offlined earlier and + * offlining timed out in common_cpu_die(). + */ + if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) { + xen_smp_intr_free(cpu); + xen_uninit_lock_cpu(cpu); + } + + xen_vcpu_setup(cpu); } + + if (xen_pv_domain() || + (xen_have_vector_callback && + xen_feature(XENFEAT_hvm_safe_pvclock))) + xen_setup_timer(cpu); + + rc = xen_smp_intr_init(cpu); + if (rc) { + WARN(1, "xen_smp_intr_init() for CPU %d failed: %d\n", + cpu, rc); + return NOTIFY_BAD; + } + + break; + case CPU_ONLINE: + xen_init_lock_cpu(cpu); + break; + case CPU_UP_CANCELED: + xen_smp_intr_free(cpu); + if (xen_pv_domain() || + (xen_have_vector_callback && + xen_feature(XENFEAT_hvm_safe_pvclock))) + xen_teardown_timer(cpu); break; default: break; @@ -1801,8 +1836,8 @@ static int xen_hvm_cpu_notify(struct notifier_block *self, unsigned long action, return NOTIFY_OK; } -static struct notifier_block xen_hvm_cpu_notifier = { - .notifier_call = xen_hvm_cpu_notify, +static struct notifier_block xen_cpu_notifier = { + .notifier_call = xen_cpu_notify, }; #ifdef CONFIG_KEXEC_CORE @@ -1834,7 +1869,7 @@ static void __init xen_hvm_guest_init(void) if (xen_feature(XENFEAT_hvm_callback_vector)) xen_have_vector_callback = 1; xen_hvm_smp_init(); - register_cpu_notifier(&xen_hvm_cpu_notifier); + register_cpu_notifier(&xen_cpu_notifier); xen_unplug_emulated_devices(); x86_init.irqs.intr_init = xen_init_IRQ; xen_hvm_init_time_ops(); diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 719cf29..09d5cc0 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -115,7 +115,7 @@ asmlinkage __visible void cpu_bringup_and_idle(int cpu) cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); } -static void xen_smp_intr_free(unsigned int cpu) +void xen_smp_intr_free(unsigned int cpu) { if (per_cpu(xen_resched_irq, cpu).irq >= 0) { unbind_from_irqhandler(per_cpu(xen_resched_irq, cpu).irq, NULL); @@ -159,7 +159,7 @@ static void xen_smp_intr_free(unsigned int cpu) per_cpu(xen_pmu_irq, cpu).name = NULL; } }; -static int xen_smp_intr_init(unsigned int cpu) +int xen_smp_intr_init(unsigned int cpu) { int rc; char *resched_name, *callfunc_name, *debug_name, *pmu_name; @@ -468,8 +468,6 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle) common_cpu_up(cpu, idle); xen_setup_runstate_info(cpu); - xen_setup_timer(cpu); - xen_init_lock_cpu(cpu); /* * PV VCPUs are always successfully taken down (see 'while' loop @@ -488,10 +486,6 @@ static int xen_cpu_up(unsigned int cpu, struct task_struct *idle) xen_pmu_init(cpu); - rc = xen_smp_intr_init(cpu); - if (rc) - return rc; - rc = HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL); BUG_ON(rc); @@ -761,47 +755,12 @@ static void __init xen_hvm_smp_prepare_cpus(unsigned int max_cpus) xen_init_lock_cpu(0); } -static int xen_hvm_cpu_up(unsigned int cpu, struct task_struct *tidle) -{ - int rc; - - /* - * This can happen if CPU was offlined earlier and - * offlining timed out in common_cpu_die(). - */ - if (cpu_report_state(cpu) == CPU_DEAD_FROZEN) { - xen_smp_intr_free(cpu); - xen_uninit_lock_cpu(cpu); - } - - /* - * xen_smp_intr_init() needs to run before native_cpu_up() - * so that IPI vectors are set up on the booting CPU before - * it is marked online in native_cpu_up(). - */ - rc = xen_smp_intr_init(cpu); - WARN_ON(rc); - if (!rc) - rc = native_cpu_up(cpu, tidle); - - /* - * We must initialize the slowpath CPU kicker _after_ the native - * path has executed. If we initialized it before none of the - * unlocker IPI kicks would reach the booting CPU as the booting - * CPU had not set itself 'online' in cpu_online_mask. That mask - * is checked when IPIs are sent (on HVM at least). - */ - xen_init_lock_cpu(cpu); - return rc; -} - void __init xen_hvm_smp_init(void) { if (!xen_have_vector_callback) return; smp_ops.smp_prepare_cpus = xen_hvm_smp_prepare_cpus; smp_ops.smp_send_reschedule = xen_smp_send_reschedule; - smp_ops.cpu_up = xen_hvm_cpu_up; smp_ops.cpu_die = xen_cpu_die; smp_ops.send_call_func_ipi = xen_smp_send_call_function_ipi; smp_ops.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi; diff --git a/arch/x86/xen/smp.h b/arch/x86/xen/smp.h index 963d62a..45faaf3 100644 --- a/arch/x86/xen/smp.h +++ b/arch/x86/xen/smp.h @@ -8,6 +8,9 @@ extern void xen_send_IPI_allbutself(int vector); extern void xen_send_IPI_all(int vector); extern void xen_send_IPI_self(int vector); +extern int xen_smp_intr_init(unsigned int cpu); +extern void xen_smp_intr_free(unsigned int cpu); + #ifdef CONFIG_XEN_PVH extern void xen_pvh_early_cpu_init(int cpu, bool entry); #else -- 1.7.1