diff options
| author |   Wei Yang <richard.weiyang@gmail.com> | 2018-09-06 05:58:16 +0800 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2018-10-17 00:29:40 +0200 |
| commit | 3ff519f29d98ecdc1961d825d105d68711093b6b (patch) | |
| tree | e291a62f70b9553f6418a4b7e7ebce4f6b1ccf10 /arch/x86/include/asm | |
| parent | KVM: nVMX: restore host state in nested_vmx_vmexit for VMFail (diff) | |
| download | linux-dev-3ff519f29d98ecdc1961d825d105d68711093b6b.tar.xz linux-dev-3ff519f29d98ecdc1961d825d105d68711093b6b.zip | |
KVM: x86: adjust kvm_mmu_page member to save 8 bytes
On a 64bits machine, struct is naturally aligned with 8 bytes. Since
kvm_mmu_page member *unsync* and *role* are less then 4 bytes, we can
rearrange the sequence to compace the struct.
As the comment shows, *role* and *gfn* are used to key the shadow page. In
order to keep the comment valid, this patch moves the *unsync* up and
exchange the position of *role* and *gfn*.
From /proc/slabinfo, it shows the size of kvm_mmu_page is 8 bytes less and
with one more object per slap after applying this patch.
# name <active_objs> <num_objs> <objsize> <objperslab>
kvm_mmu_page_header 0 0 168 24
kvm_mmu_page_header 0 0 160 25
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/include/asm')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 1c09a0d1771f..576ff47a79c4 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -281,18 +281,18 @@ struct kvm_rmap_head { struct kvm_mmu_page { struct list_head link; struct hlist_node hash_link; + bool unsync; /* * The following two entries are used to key the shadow page in the * hash table. */ - gfn_t gfn; union kvm_mmu_page_role role; + gfn_t gfn; u64 *spt; /* hold the gfn of each spte inside spt */ gfn_t *gfns; - bool unsync; int root_count; /* Currently serving as active root */ unsigned int unsync_children; struct kvm_rmap_head parent_ptes; /* rmap pointers to parent sptes */ |