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From: Marc Zyngier <maz@kernel.org>
To: Gavin Shan <gshan@redhat.com>
Cc: kernel-team@android.com, Will Deacon <will@kernel.org>,
	kvmarm@lists.cs.columbia.edu
Subject: Re: [PATCH] KVM: arm64: Allocate stage-2 pgd pages with GFP_KERNEL_ACCOUNT
Date: Tue, 27 Oct 2020 09:27:05 +0000	[thread overview]
Message-ID: <bb240736aae6315df28c90463e1c8801@kernel.org> (raw)
In-Reply-To: <962c401d-4376-7ecf-1a8b-b6ad91ecfe68@redhat.com>

On 2020-10-26 23:41, Gavin Shan wrote:
> Hi Will,
> 
> On 10/27/20 1:44 AM, Will Deacon wrote:
>> For consistency with the rest of the stage-2 page-table page 
>> allocations
>> (performing using a kvm_mmu_memory_cache), ensure that __GFP_ACCOUNT 
>> is
>> included in the GFP flags for the PGD pages.
>> 
>> Cc: Marc Zyngier <maz@kernel.org>
>> Cc: Quentin Perret <qperret@google.com>
>> Signed-off-by: Will Deacon <will@kernel.org>
>> ---
>>   arch/arm64/kvm/hyp/pgtable.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>> 
> 
> The patch itself looks good to me:
> 
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> 
> Another question is why the page-table pages for hyp mode aren't
> allocated with __GFP_ACCOUNT in kvm_pgtable_hyp_init and 
> hyp_map_walker()?

Why user task would you account the hypervisor mappings to? The page 
tables
used for HYP code and data are definitely not attributable to any task.

The kvm and kvm_vcpu mappings *could* be attributed to a user task, but
the page tables are likely shared with other tasks. So who gets the 
blame?

         M.
-- 
Jazz is not dead. It just smells funny...
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  reply	other threads:[~2020-10-27  9:27 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-26 14:44 [PATCH] KVM: arm64: Allocate stage-2 pgd pages with GFP_KERNEL_ACCOUNT Will Deacon
2020-10-26 23:41 ` Gavin Shan
2020-10-27  9:27   ` Marc Zyngier [this message]
2020-10-28  5:56     ` Gavin Shan
2020-10-28  8:56       ` Marc Zyngier
2020-10-27  9:27   ` Will Deacon
2020-10-28  5:52     ` Gavin Shan
2020-10-29 21:09 ` Marc Zyngier
2020-10-29 21:09   ` Marc Zyngier

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