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From: Marcelo Tosatti <mtosatti@redhat.com>
To: Avi Kivity <avi@redhat.com>
Cc: kvm-devel <kvm@vger.kernel.org>
Subject: KVM: MMU: drop zeroing on mmu_memory_cache_alloc
Date: Thu, 8 Jan 2009 17:44:19 -0200	[thread overview]
Message-ID: <20090108194419.GA8176@amt.cnet> (raw)


Zeroing on mmu_memory_cache_alloc is unnecessary since:

- Smaller areas are pre-allocated with kmem_cache_zalloc.
- Page pointed by ->spt is overwritten with prefetch_page 
  and entries in page pointed by ->gfns are initialized 
  before reading.

[avi: zeroing pages is unnecessary]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 10bdb2a..823d0cd 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -352,7 +352,6 @@ static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc,
 
 	BUG_ON(!mc->nobjs);
 	p = mc->objects[--mc->nobjs];
-	memset(p, 0, size);
 	return p;
 }
 


             reply	other threads:[~2009-01-08 19:44 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-08 19:44 Marcelo Tosatti [this message]
2009-01-11  7:14 ` KVM: MMU: drop zeroing on mmu_memory_cache_alloc Avi Kivity

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