RE: [PATCH 2/2] KVM: arm64: Add memcg accounting to KVM allocations

-----Original Message-----
From: Marc Zyngier <maz@kernel.org>
Sent: Friday, September 3, 2021 2:12 AM
To: Justin He <redacted>
Cc: James Morse <James.Morse@arm.com>; Alexandru Elisei
[off-list ref]; Suzuki Poulose [off-list ref];
Catalin Marinas [off-list ref]; Will Deacon [off-list ref];
Liu Shixin [off-list ref]; Eric Auger [off-list ref];
Kees Cook [off-list ref]; Nick Desaulniers
[off-list ref]; Shenming Lu [off-list ref]; Sami
Tolvanen [off-list ref]; Lorenzo Pieralisi
[off-list ref]; Xiaoming Ni [off-list ref]; Zenghui
Yu [off-list ref]; linux-arm-kernel@lists.infradead.org;
kvmarm@lists.cs.columbia.edu; linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] KVM: arm64: Add memcg accounting to KVM
allocations

On Thu, 02 Sep 2021 01:28:01 +0100,
Jia He [off-list ref] wrote:

quoted

Inspired by commit 254272ce6505 ("kvm: x86: Add memcg accounting to KVM
allocations"), it would be better to make arm64 KVM consistent with
common kvm codes.

The memory allocations of VM scope should be charged into VM process
cgroup, hence change GFP_KERNEL to GFP_KERNEL_ACCOUNT.

There remained a few cases since these allocations are global, not in VM
scope.

Signed-off-by: Jia He <redacted>
---
 arch/arm64/kvm/arm.c      | 6 ++++--
 arch/arm64/kvm/mmu.c      | 2 +-
 arch/arm64/kvm/pmu-emul.c | 2 +-
 arch/arm64/kvm/reset.c    | 2 +-
 4 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index e9a2b8f27792..9d6f5bcaddef 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c

@@ -289,10 +289,12 @@ long kvm_arch_dev_ioctl(struct file *filp,

 struct kvm *kvm_arch_alloc_vm(void)
 {
+	unsigned long sz = sizeof(struct kvm);

If you are going to introduce an extra variable, please use the
correct type (size_t).

Okay

quoted

+
 	if (!has_vhe())
-		return kzalloc(sizeof(struct kvm), GFP_KERNEL);
+		return kzalloc(sz, GFP_KERNEL | GFP_KERNEL_ACCOUNT);

Why both GFP_KERNEL and GFP_KERNEL_ACCOUNT?

Urgh, sorry for the mistake.

--
Cheers,
Justin (Jia He)



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