From e73f61e41f3bb9bc453fd9c21b82d0b89c2b83e7 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Fri, 8 May 2015 14:31:44 +0200 Subject: kvm: irqchip: Break up high order allocations of kvm_irq_routing_table The allocation size of the kvm_irq_routing_table depends on the number of irq routing entries because they are all allocated with one kzalloc call. When the irq routing table gets bigger this requires high order allocations which fail from time to time: qemu-kvm: page allocation failure: order:4, mode:0xd0 This patch fixes this issue by breaking up the allocation of the table and its entries into individual kzalloc calls. These could all be satisfied with order-0 allocations, which are less likely to fail. The downside of this change is the lower performance, because of more calls to kzalloc. But given how often kvm_set_irq_routing is called in the lifetime of a guest, it doesn't really matter much. Signed-off-by: Joerg Roedel [Avoid sparse warning through rcu_access_pointer. - Paolo] Signed-off-by: Paolo Bonzini --- virt/kvm/irqchip.c | 41 +++++++++++++++++++++++++++++++++-------- 1 file changed, 33 insertions(+), 8 deletions(-) (limited to 'virt') diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c index 1d56a901e791..21c14244f4c4 100644 --- a/virt/kvm/irqchip.c +++ b/virt/kvm/irqchip.c @@ -33,7 +33,6 @@ struct kvm_irq_routing_table { int chip[KVM_NR_IRQCHIPS][KVM_IRQCHIP_NUM_PINS]; - struct kvm_kernel_irq_routing_entry *rt_entries; u32 nr_rt_entries; /* * Array indexed by gsi. Each entry contains list of irq chips @@ -118,11 +117,32 @@ int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level, return ret; } +static void free_irq_routing_table(struct kvm_irq_routing_table *rt) +{ + int i; + + if (!rt) + return; + + for (i = 0; i < rt->nr_rt_entries; ++i) { + struct kvm_kernel_irq_routing_entry *e; + struct hlist_node *n; + + hlist_for_each_entry_safe(e, n, &rt->map[i], link) { + hlist_del(&e->link); + kfree(e); + } + } + + kfree(rt); +} + void kvm_free_irq_routing(struct kvm *kvm) { /* Called only during vm destruction. Nobody can use the pointer at this stage */ - kfree(kvm->irq_routing); + struct kvm_irq_routing_table *rt = rcu_access_pointer(kvm->irq_routing); + free_irq_routing_table(rt); } static int setup_routing_entry(struct kvm_irq_routing_table *rt, @@ -173,25 +193,29 @@ int kvm_set_irq_routing(struct kvm *kvm, nr_rt_entries += 1; - new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head)) - + (nr * sizeof(struct kvm_kernel_irq_routing_entry)), + new = kzalloc(sizeof(*new) + (nr_rt_entries * sizeof(struct hlist_head)), GFP_KERNEL); if (!new) return -ENOMEM; - new->rt_entries = (void *)&new->map[nr_rt_entries]; - new->nr_rt_entries = nr_rt_entries; for (i = 0; i < KVM_NR_IRQCHIPS; i++) for (j = 0; j < KVM_IRQCHIP_NUM_PINS; j++) new->chip[i][j] = -1; for (i = 0; i < nr; ++i) { + struct kvm_kernel_irq_routing_entry *e; + + r = -ENOMEM; + e = kzalloc(sizeof(*e), GFP_KERNEL); + if (!e) + goto out; + r = -EINVAL; if (ue->flags) goto out; - r = setup_routing_entry(new, &new->rt_entries[i], ue); + r = setup_routing_entry(new, e, ue); if (r) goto out; ++ue; @@ -209,6 +233,7 @@ int kvm_set_irq_routing(struct kvm *kvm, r = 0; out: - kfree(new); + free_irq_routing_table(new); + return r; } -- cgit v1.2.3