Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753130AbbEHMb7 (ORCPT ); Fri, 8 May 2015 08:31:59 -0400 Received: from 8bytes.org ([81.169.241.247]:52409 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752681AbbEHMbz (ORCPT ); Fri, 8 May 2015 08:31:55 -0400 From: Joerg Roedel To: Gleb Natapov , Paolo Bonzini Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Joerg Roedel Subject: [PATCH] kvm: irqchip: Break up high order allocations of kvm_irq_routing_table Date: Fri, 8 May 2015 14:31:44 +0200 Message-Id: <1431088304-11365-1-git-send-email-joro@8bytes.org> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3335 Lines: 123 From: Joerg Roedel 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 --- virt/kvm/irqchip.c | 40 ++++++++++++++++++++++++++++++++-------- 1 file changed, 32 insertions(+), 8 deletions(-) diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c index 1d56a90..b56168f 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 +117,31 @@ 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); + free_irq_routing_table(kvm->irq_routing); } static int setup_routing_entry(struct kvm_irq_routing_table *rt, @@ -173,25 +192,29 @@ 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 +232,7 @@ int kvm_set_irq_routing(struct kvm *kvm, r = 0; out: - kfree(new); + free_irq_routing_table(new); + return r; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/