From: William Tu <u9012063@gmail.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>,
Linux Kernel Network Developers <netdev@vger.kernel.org>
Subject: Re: [PATCH] bpf: fix size of copy_to_user in percpu map.
Date: Thu, 18 Aug 2016 18:38:20 -0700 [thread overview]
Message-ID: <CALDO+Sa6P-Qo5OqJELcak2nUKMAwdMuAxrDKASCJ_oJRPFsKjQ@mail.gmail.com> (raw)
In-Reply-To: <20160812230810.GB48651@ast-mbp.thefacebook.com>
Hi Alexei and Daniel,
I got feedback from Fusion bios/chipset team. In short, the value
'possible' includes empty CPU socket. To verify, I tested on a
physical Xeon machine with 2 CPU sockets, one of them is empty. I got
'possible' = 0-239, the number of 'cpu*' =12. As a result, extra bytes
are copied from kernel to userspace.
As for Fusion, there is a configuration in *.vmx. If we disable cpu
hot plug by "vcpu.hotadd=FALSE", then 'possible' == the number of
'cpu*' dirs, which is the configuration in ESX. If "vcpu.hotadd=TURE",
then 'possible' is larger than 'cpu*' dirs, allowing users to add more
vcpus.
Regards,
William
On Fri, Aug 12, 2016 at 4:08 PM, Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
> On Fri, Aug 12, 2016 at 09:58:51AM -0700, William Tu wrote:
>> Hi,
>>
>> I've tested on ESXi version 5.5 and it seems OK.
>> - VM1: Ubuntu 14.04, kernel 3.19 ---> OK 3 cpu dirs, possible = 0-2
>> - VM2: Centos7, kernel 3.10 ---> OK 8 cpu dirs, possible = 0-7
>>
>> I tried another MacBook with Fusion, same issue happens, the cpu[0-9]
>> dirs are not equal to /sys/devices/system/cpu/possible
>
> great. thanks for testing. I think the issue is closed and
> hopefully you can follow up with fusion guys ;)
>
next prev parent reply other threads:[~2016-08-19 1:39 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-29 0:42 [PATCH] bpf: fix size of copy_to_user in percpu map William Tu
2016-07-29 6:47 ` Alexei Starovoitov
2016-07-29 7:54 ` Daniel Borkmann
2016-07-29 20:03 ` William Tu
2016-07-30 0:19 ` Daniel Borkmann
2016-07-30 5:23 ` William Tu
2016-07-30 5:34 ` Alexei Starovoitov
2016-07-31 15:25 ` William Tu
2016-08-01 16:07 ` Alexei Starovoitov
2016-08-01 16:30 ` William Tu
2016-08-12 16:58 ` William Tu
2016-08-12 23:08 ` Alexei Starovoitov
2016-08-19 1:38 ` William Tu [this message]
2016-08-24 23:46 ` William Tu
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