Commit 2e3e5882 authored by Avi Kivity's avatar Avi Kivity

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: default avatarAvi Kivity <avi@qumranet.com>
parent cbdd1bea
......@@ -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);
......
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