From: "Huang, Kai" <kai.huang@intel.com>
To: "seanjc@google.com" <seanjc@google.com>
Cc: "x86@kernel.org" <x86@kernel.org>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"hpa@zytor.com" <hpa@zytor.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"bp@alien8.de" <bp@alien8.de>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"zhangxiaoxu5@huawei.com" <zhangxiaoxu5@huawei.com>,
"liuyongqiang13@huawei.com" <liuyongqiang13@huawei.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>
Subject: Re: [PATCH -next] KVM: SVM: Remove unnecessary GFP_KERNEL_ACCOUNT in svm_set_nested_state()
Date: Sat, 24 Aug 2024 09:33:40 +0000 [thread overview]
Message-ID: <e21beaa7c31639f9e8836f963f16c23ee982329f.camel@intel.com> (raw)
In-Reply-To: <Zskil6dbwJmL93cO@google.com>
On Fri, 2024-08-23 at 17:00 -0700, Sean Christopherson wrote:
> On Fri, Aug 23, 2024, Kai Huang wrote:
> >
> >
> > On 21/08/2024 11:27 pm, Yongqiang Liu wrote:
> > > The fixed size temporary variables vmcb_control_area and vmcb_save_area
> > > allocated in svm_set_nested_state() are released when the function exits.
> > > Meanwhile, svm_set_nested_state() also have vcpu mutex held to avoid
> > > massive concurrency allocation, so we don't need to set GFP_KERNEL_ACCOUNT.
> >
> > Hi Sean/Paolo,
> >
> > Seems more patches are popping up regarding to whether to use _ACCOUNT for
> > temporary memory allocation. Could we have a definitive guide on this?
>
> If the allocations are temporary, e.g. scoped to exactly one function, not massive
> (use best judgment), and can't be used in any kind of novel DDoS attack, e.g. are
> limited to one per vCPU or so, then they don't need to be accounted.
>
> At least, that's my take on things.
That makes sense. Thanks.
next prev parent reply other threads:[~2024-08-24 9:33 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-08-21 11:27 Yongqiang Liu
2024-08-23 0:03 ` Huang, Kai
2024-08-24 0:00 ` Sean Christopherson
2024-08-24 9:33 ` Huang, Kai [this message]
2024-08-23 23:47 ` Sean Christopherson
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