From 2e3e5882dca3ab409aa8c9c96f47610b576719f8 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Mon, 10 Sep 2007 11:28:17 +0300 Subject: [PATCH] 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 --- drivers/kvm/mmu.c | 34 ++++++++++------------------------ 1 file changed, 10 insertions(+), 24 deletions(-) diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c index 7b42c88b0b57..6d84d30f5ed0 100644 --- a/drivers/kvm/mmu.c +++ b/drivers/kvm/mmu.c @@ -202,15 +202,14 @@ static void set_shadow_pte(u64 *sptep, u64 spte) } static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, - struct kmem_cache *base_cache, int min, - gfp_t gfp_flags) + struct kmem_cache *base_cache, int min) { void *obj; if (cache->nobjs >= min) return 0; while (cache->nobjs < ARRAY_SIZE(cache->objects)) { - obj = kmem_cache_zalloc(base_cache, gfp_flags); + obj = kmem_cache_zalloc(base_cache, GFP_KERNEL); if (!obj) return -ENOMEM; cache->objects[cache->nobjs++] = obj; @@ -225,14 +224,14 @@ static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc) } static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache, - int min, gfp_t gfp_flags) + int min) { struct page *page; if (cache->nobjs >= min) return 0; while (cache->nobjs < ARRAY_SIZE(cache->objects)) { - page = alloc_page(gfp_flags); + page = alloc_page(GFP_KERNEL); if (!page) return -ENOMEM; set_page_private(page, 0); @@ -247,41 +246,28 @@ static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc) free_page((unsigned long)mc->objects[--mc->nobjs]); } -static int __mmu_topup_memory_caches(struct kvm_vcpu *vcpu, gfp_t gfp_flags) +static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu) { int r; + kvm_mmu_free_some_pages(vcpu); r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache, - pte_chain_cache, 4, gfp_flags); + pte_chain_cache, 4); if (r) goto out; r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache, - rmap_desc_cache, 1, gfp_flags); + rmap_desc_cache, 1); if (r) goto out; - r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 4, gfp_flags); + r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 4); if (r) goto out; r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache, - mmu_page_header_cache, 4, gfp_flags); + mmu_page_header_cache, 4); out: return r; } -static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu) -{ - int r; - - r = __mmu_topup_memory_caches(vcpu, GFP_NOWAIT); - kvm_mmu_free_some_pages(vcpu); - if (r < 0) { - mutex_unlock(&vcpu->kvm->lock); - r = __mmu_topup_memory_caches(vcpu, GFP_KERNEL); - mutex_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); -- 2.20.1