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authorAvi Kivity <avi@qumranet.com>2007-09-10 04:28:17 -0400
committerAvi Kivity <avi@qumranet.com>2007-10-13 04:18:27 -0400
commit2e3e5882dca3ab409aa8c9c96f47610b576719f8 (patch)
tree53184e9026b67710bd74615b818c53a6b62c3ab4 /drivers/kvm
parentcbdd1bea2a2dce4c0b45c5f0122c150d9f07f0bc (diff)
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>
Diffstat (limited to 'drivers/kvm')
-rw-r--r--drivers/kvm/mmu.c34
1 files 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)
202} 202}
203 203
204static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, 204static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache,
205 struct kmem_cache *base_cache, int min, 205 struct kmem_cache *base_cache, int min)
206 gfp_t gfp_flags)
207{ 206{
208 void *obj; 207 void *obj;
209 208
210 if (cache->nobjs >= min) 209 if (cache->nobjs >= min)
211 return 0; 210 return 0;
212 while (cache->nobjs < ARRAY_SIZE(cache->objects)) { 211 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
213 obj = kmem_cache_zalloc(base_cache, gfp_flags); 212 obj = kmem_cache_zalloc(base_cache, GFP_KERNEL);
214 if (!obj) 213 if (!obj)
215 return -ENOMEM; 214 return -ENOMEM;
216 cache->objects[cache->nobjs++] = obj; 215 cache->objects[cache->nobjs++] = obj;
@@ -225,14 +224,14 @@ static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc)
225} 224}
226 225
227static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache, 226static int mmu_topup_memory_cache_page(struct kvm_mmu_memory_cache *cache,
228 int min, gfp_t gfp_flags) 227 int min)
229{ 228{
230 struct page *page; 229 struct page *page;
231 230
232 if (cache->nobjs >= min) 231 if (cache->nobjs >= min)
233 return 0; 232 return 0;
234 while (cache->nobjs < ARRAY_SIZE(cache->objects)) { 233 while (cache->nobjs < ARRAY_SIZE(cache->objects)) {
235 page = alloc_page(gfp_flags); 234 page = alloc_page(GFP_KERNEL);
236 if (!page) 235 if (!page)
237 return -ENOMEM; 236 return -ENOMEM;
238 set_page_private(page, 0); 237 set_page_private(page, 0);
@@ -247,41 +246,28 @@ static void mmu_free_memory_cache_page(struct kvm_mmu_memory_cache *mc)
247 free_page((unsigned long)mc->objects[--mc->nobjs]); 246 free_page((unsigned long)mc->objects[--mc->nobjs]);
248} 247}
249 248
250static int __mmu_topup_memory_caches(struct kvm_vcpu *vcpu, gfp_t gfp_flags) 249static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
251{ 250{
252 int r; 251 int r;
253 252
253 kvm_mmu_free_some_pages(vcpu);
254 r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache, 254 r = mmu_topup_memory_cache(&vcpu->mmu_pte_chain_cache,
255 pte_chain_cache, 4, gfp_flags); 255 pte_chain_cache, 4);
256 if (r) 256 if (r)
257 goto out; 257 goto out;
258 r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache, 258 r = mmu_topup_memory_cache(&vcpu->mmu_rmap_desc_cache,
259 rmap_desc_cache, 1, gfp_flags); 259 rmap_desc_cache, 1);
260 if (r) 260 if (r)
261 goto out; 261 goto out;
262 r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 4, gfp_flags); 262 r = mmu_topup_memory_cache_page(&vcpu->mmu_page_cache, 4);
263 if (r) 263 if (r)
264 goto out; 264 goto out;
265 r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache, 265 r = mmu_topup_memory_cache(&vcpu->mmu_page_header_cache,
266 mmu_page_header_cache, 4, gfp_flags); 266 mmu_page_header_cache, 4);
267out: 267out:
268 return r; 268 return r;
269} 269}
270 270
271static int mmu_topup_memory_caches(struct kvm_vcpu *vcpu)
272{
273 int r;
274
275 r = __mmu_topup_memory_caches(vcpu, GFP_NOWAIT);
276 kvm_mmu_free_some_pages(vcpu);
277 if (r < 0) {
278 mutex_unlock(&vcpu->kvm->lock);
279 r = __mmu_topup_memory_caches(vcpu, GFP_KERNEL);
280 mutex_lock(&vcpu->kvm->lock);
281 }
282 return r;
283}
284
285static void mmu_free_memory_caches(struct kvm_vcpu *vcpu) 271static void mmu_free_memory_caches(struct kvm_vcpu *vcpu)
286{ 272{
287 mmu_free_memory_cache(&vcpu->mmu_pte_chain_cache); 273 mmu_free_memory_cache(&vcpu->mmu_pte_chain_cache);