From: "Jarkko Sakkinen" <jarkko@kernel.org>
To: "Tejun Heo" <tj@kernel.org>,
"Haitao Huang" <haitao.huang@linux.intel.com>
Cc: <dave.hansen@linux.intel.com>, <linux-kernel@vger.kernel.org>,
<linux-sgx@vger.kernel.org>, <cgroups@vger.kernel.org>,
"Zefan Li" <lizefan.x@bytedance.com>,
"Johannes Weiner" <hannes@cmpxchg.org>, <vipinsh@google.com>,
<kai.huang@intel.com>, <reinette.chatre@intel.com>,
<zhiquan1.li@intel.com>, <kristen@linux.intel.com>
Subject: Re: [PATCH] cgroup/misc: Fix an overflow
Date: Tue, 18 Jul 2023 18:41:27 +0300 [thread overview]
Message-ID: <CU5EUJDXM616.SQKBEGB2RLHL@suppilovahvero> (raw)
In-Reply-To: <ZLWmdBfcuPUBtk1K@slm.duckdns.org>
On Mon Jul 17, 2023 at 11:37 PM EEST, Tejun Heo wrote:
> Hello,
>
> On Mon, Jul 17, 2023 at 03:19:38PM -0500, Haitao Huang wrote:
> > Actually, we are using atomic_long_t for 'current' which is the same width
> > as long defined by arch/compiler. So new_usage should be long to be
> > consistent?
>
> We can use atomic64_t, right? It's slower on 32bit machines but I think it'd
> be better to guarantee resource counter range than micro-optimizing charge
> operations. None of the current users are hot enough for this to matter and
> if somebody becomes that hot, the difference between atomic_t and atomic64_t
> isn't gonna matter that much. We'd need to batch allocations per-cpu and so
> on.
In our context, the microcode of SGX could support 32-bit but by design
we only support 64-bit. So at least with the current implementation this
would not be an issue for SGX.
BR, Jarkko
prev parent reply other threads:[~2023-07-18 15:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-17 18:47 [PATCH] cgroup/misc: Fix an overflow Haitao Huang
2023-07-17 18:51 ` Tejun Heo
2023-07-17 18:55 ` Jarkko Sakkinen
2023-07-17 18:57 ` Tejun Heo
2023-07-17 19:01 ` Haitao Huang
2023-07-17 20:19 ` Haitao Huang
2023-07-17 20:37 ` Tejun Heo
2023-07-18 1:08 ` [PATCH 1/2] " Haitao Huang
2023-07-18 1:08 ` [PATCH 2/2] cgroup/misc: Change counters to be explicit 64bit types Haitao Huang
2023-07-18 22:52 ` Tejun Heo
2023-07-21 2:48 ` Haitao Huang
2023-07-21 12:02 ` [PATCH] cgroup/misc: Store atomic64_t reads to u64 Haitao Huang
2023-07-21 18:10 ` Tejun Heo
2023-07-18 1:11 ` [PATCH] cgroup/misc: Fix an overflow Haitao Huang
2023-07-18 15:41 ` Jarkko Sakkinen [this message]
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