From: Dave Hansen <dave.hansen@intel.com>
To: "Reshetova, Elena" <elena.reshetova@intel.com>
Cc: "jarkko@kernel.org" <jarkko@kernel.org>,
"seanjc@google.com" <seanjc@google.com>,
"Huang, Kai" <kai.huang@intel.com>,
"mingo@kernel.org" <mingo@kernel.org>,
"linux-sgx@vger.kernel.org" <linux-sgx@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"x86@kernel.org" <x86@kernel.org>,
"Mallick, Asit K" <asit.k.mallick@intel.com>,
"Scarlata, Vincent R" <vincent.r.scarlata@intel.com>,
"Cai, Chong" <chongc@google.com>,
"Aktas, Erdem" <erdemaktas@google.com>,
"Annapurve, Vishal" <vannapurve@google.com>,
"dionnaglaze@google.com" <dionnaglaze@google.com>,
"Bondarevska, Nataliia" <bondarn@google.com>,
"Raynor, Scott" <scott.raynor@intel.com>
Subject: Re: [PATCH v7 5/5] x86/sgx: Enable automatic SVN updates for SGX enclaves
Date: Mon, 14 Jul 2025 06:54:50 -0700 [thread overview]
Message-ID: <2cd81800-12ba-460e-ac28-4532d0be1ec9@intel.com> (raw)
In-Reply-To: <DM8PR11MB57503EC8DF105A7D7FF02303E754A@DM8PR11MB5750.namprd11.prod.outlook.com>
On 7/14/25 00:35, Reshetova, Elena wrote:
> I think you put it: this would require a spinlock in the fast path and
> *in theory* if we are running many many concurrent enclaves can create
> contention
FWIW, my mental model is that spinlocks that are held for short periods
of time are pretty much the same cost as an atomic under contention.
If there are lots of users, the cost of moving the cacheline for the
atomic or the spinlock dominates everything else. It doesn't matter
whether that cacheline is an atomic_t or spinlock_t.
The only difference is that there is _visible_ spinning for a spinlock.
next prev parent reply other threads:[~2025-07-14 13:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-11 16:50 [PATCH v7 0/5] " Elena Reshetova
2025-07-11 16:50 ` [PATCH v7 1/5] x86/sgx: Introduce a counter to count the sgx_(vepc_)open() Elena Reshetova
2025-07-11 16:50 ` [PATCH v7 2/5] x86/cpufeatures: Add X86_FEATURE_SGX_EUPDATESVN feature flag Elena Reshetova
2025-07-11 16:50 ` [PATCH v7 3/5] x86/sgx: Define error codes for use by ENCLS[EUPDATESVN] Elena Reshetova
2025-07-11 16:50 ` [PATCH v7 4/5] x86/sgx: Implement ENCLS[EUPDATESVN] Elena Reshetova
2025-07-11 16:50 ` [PATCH v7 5/5] x86/sgx: Enable automatic SVN updates for SGX enclaves Elena Reshetova
2025-07-11 17:54 ` Dave Hansen
2025-07-14 7:35 ` Reshetova, Elena
2025-07-14 13:54 ` Dave Hansen [this message]
2025-07-14 15:37 ` Dave Hansen
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