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Commit 8c438502 authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: Retry sleeping allocation if atomic allocation fails 



This avoids -ENOMEM under memory pressure.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent b5a33a75

drivers/kvm/mmu.c

+21 −5
Original line number Diff line number Diff line
@@ -199,14 +199,15 @@ static int is_rmap_pte(u64 pte) 
}



static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,

				  struct kmem_cache *base_cache, int min)

				  struct kmem_cache *base_cache, int min,

				  gfp_t gfp_flags)

{

	void *obj;



	if (cache->nobjs >= min)

		return 0;

	while (cache->nobjs < ARRAY_SIZE(cache->objects)) {

		obj = kmem_cache_zalloc(base_cache, GFP_NOWAIT);

		obj = kmem_cache_zalloc(base_cache, gfp_flags);

		if (!obj)

			return -ENOMEM;

		cache->objects[cache->nobjs++] = obj;
@@ -220,20 +221,35 @@ static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc) 
		kfree(mc->objects[--mc->nobjs]);

}



static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)

static int __mmu_topup_memory_caches(struct kvm_vcpu *vcpu, gfp_t gfp_flags)

{

	int r;



	r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache,

				   pte_chain_cache, 4);

				   pte_chain_cache, 4, gfp_flags);

	if (r)

		goto out;

	r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,

				   rmap_desc_cache, 1);

				   rmap_desc_cache, 1, gfp_flags);

out:

	return r;

}



static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)

{

	int r;



	r = __mmu_topup_memory_caches(vcpu, GFP_NOWAIT);

	if (r < 0) {

		spin_unlock(&vcpu->kvm->lock);

		kvm_arch_ops->vcpu_put(vcpu);

		r = __mmu_topup_memory_caches(vcpu, GFP_KERNEL);

		kvm_arch_ops->vcpu_load(vcpu);

		spin_lock(&vcpu->kvm->lock);

	}

	return r;

}



static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)

{

	mmu_free_memory_cache(&vcpu->mmu_pte_chain_cache);