forked from Minki/linux
KVM: MMU: Don't do GFP_NOWAIT allocations
Before preempt notifiers, kvm needed to allocate memory with GFP_NOWAIT so as not to have to enable preemption and take a heavyweight exit. On oom, we'd fall back to a GFP_KERNEL allocation. With preemption notifiers, we can do a GFP_KERNEL allocation, and perform the heavyweight exit only if the kernel decides to put us to sleep. Signed-off-by: Avi Kivity <avi@qumranet.com>
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cbdd1bea2a
commit
2e3e5882dc
@ -202,15 +202,14 @@ static void set_shadow_pte(u64 *sptep, u64 spte)
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}
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static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
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struct kmem_cache *base_cache, int min,
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gfp_t gfp_flags)
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struct kmem_cache *base_cache, int min)
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{
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void *obj;
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if (cache->nobjs >= min)
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return 0;
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while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
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obj = kmem_cache_zalloc(base_cache, gfp_flags);
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obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
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if (!obj)
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return -ENOMEM;
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cache->objects[cache->nobjs++] = obj;
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@ -225,14 +224,14 @@ static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
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}
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static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
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int min, gfp_t gfp_flags)
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int min)
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{
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struct page *page;
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if (cache->nobjs >= min)
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return 0;
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while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
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page = alloc_page(gfp_flags);
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page = alloc_page(GFP_KERNEL);
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if (!page)
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return -ENOMEM;
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set_page_private(page, 0);
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@ -247,38 +246,25 @@ static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
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free_page((unsigned long)mc->objects[--mc->nobjs]);
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}
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static int __mmu_topup_memory_caches(struct kvm_vcpu *vcpu, gfp_t gfp_flags)
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{
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int r;
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r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache,
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pte_chain_cache, 4, gfp_flags);
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if (r)
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goto out;
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r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,
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rmap_desc_cache, 1, gfp_flags);
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if (r)
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goto out;
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r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 4, gfp_flags);
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if (r)
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goto out;
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r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache,
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mmu_page_header_cache, 4, gfp_flags);
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out:
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return r;
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}
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static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
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{
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int r;
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r = __mmu_topup_memory_caches(vcpu, GFP_NOWAIT);
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kvm_mmu_free_some_pages(vcpu);
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if (r < 0) {
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mutex_unlock(&vcpu->kvm->lock);
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r = __mmu_topup_memory_caches(vcpu, GFP_KERNEL);
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mutex_lock(&vcpu->kvm->lock);
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}
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r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache,
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pte_chain_cache, 4);
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if (r)
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goto out;
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r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,
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rmap_desc_cache, 1);
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if (r)
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goto out;
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r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 4);
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if (r)
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goto out;
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r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache,
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mmu_page_header_cache, 4);
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out:
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return r;
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}
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