diff options
author | Dave Hansen <dave@linux.vnet.ibm.com> | 2008-08-11 10:01:49 -0700 |
---|---|---|
committer | Avi Kivity <avi@qumranet.com> | 2008-10-15 10:15:18 +0200 |
commit | 6ad18fba05228fb1d47cdbc0339fe8b3fca1ca26 (patch) | |
tree | 4b64607dad75aa55dd397784d469d03244f0dfe7 /arch/x86 | |
parent | b772ff362ec6b821c8a5227a3355e263f917bfad (diff) |
KVM: Reduce stack usage in kvm_pv_mmu_op()
We're in a hot path. We can't use kmalloc() because
it might impact performance. So, we just stick the buffer that
we need into the kvm_vcpu_arch structure. This is used very
often, so it is not really a waste.
We also have to move the buffer structure's definition to the
arch-specific x86 kvm header.
Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/kvm/mmu.c | 23 |
1 files changed, 8 insertions, 15 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index c3afbfe6b0c..171bcea1be2 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -135,13 +135,6 @@ module_param(dbg, bool, 0644); #define ACC_USER_MASK PT_USER_MASK #define ACC_ALL (ACC_EXEC_MASK | ACC_WRITE_MASK | ACC_USER_MASK) -struct kvm_pv_mmu_op_buffer { - void *ptr; - unsigned len; - unsigned processed; - char buf[512] __aligned(sizeof(long)); -}; - struct kvm_rmap_desc { u64 *shadow_ptes[RMAP_EXT]; struct kvm_rmap_desc *more; @@ -2292,18 +2285,18 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes, gpa_t addr, unsigned long *ret) { int r; - struct kvm_pv_mmu_op_buffer buffer; + struct kvm_pv_mmu_op_buffer *buffer = &vcpu->arch.mmu_op_buffer; - buffer.ptr = buffer.buf; - buffer.len = min_t(unsigned long, bytes, sizeof buffer.buf); - buffer.processed = 0; + buffer->ptr = buffer->buf; + buffer->len = min_t(unsigned long, bytes, sizeof buffer->buf); + buffer->processed = 0; - r = kvm_read_guest(vcpu->kvm, addr, buffer.buf, buffer.len); + r = kvm_read_guest(vcpu->kvm, addr, buffer->buf, buffer->len); if (r) goto out; - while (buffer.len) { - r = kvm_pv_mmu_op_one(vcpu, &buffer); + while (buffer->len) { + r = kvm_pv_mmu_op_one(vcpu, buffer); if (r < 0) goto out; if (r == 0) @@ -2312,7 +2305,7 @@ int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes, r = 1; out: - *ret = buffer.processed; + *ret = buffer->processed; return r; } |