Re: [PATCH v3 3/4] x86, mpx: add prctl commands PR_MPX_INIT, PR_MPX_RELEASE

From: Ren Qiaowei <qiaowei.ren@intel.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH v3 3/4] x86, mpx: add prctl commands PR_MPX_INIT, PR_MPX_RELEASE
Date: Sun, 26 Jan 2014 16:23:14 +0800	[thread overview]
Message-ID: <52E4C5F2.8070707@intel.com> (raw)
In-Reply-To: <20140126082201.GB28831@gmail.com>

On 01/26/2014 04:22 PM, Ingo Molnar wrote:
>
> * Qiaowei Ren <qiaowei.ren@intel.com> wrote:
>
>> This patch adds the PR_MPX_INIT and PR_MPX_RELEASE prctl()
>> commands on the x86 platform. These commands can be used to
>> init and release MPX related resource.
>>
>> A MMU notifier will be registered during PR_MPX_INIT
>> command execution. So the bound tables can be automatically
>> deallocated when one memory area is unmapped.
>>
>> Signed-off-by: Qiaowei Ren <qiaowei.ren@intel.com>
>> ---
>>   arch/x86/Kconfig                 |    4 ++
>>   arch/x86/include/asm/mpx.h       |    9 ++++
>>   arch/x86/include/asm/processor.h |   16 +++++++
>>   arch/x86/kernel/mpx.c            |   84 ++++++++++++++++++++++++++++++++++++++
>>   include/uapi/linux/prctl.h       |    6 +++
>>   kernel/sys.c                     |   12 +++++
>>   6 files changed, 131 insertions(+), 0 deletions(-)
>
> Hm. What is the expected typical frequency of these syscalls for a
> larger application like a web browser? Only once per startup
> typically, or will they be called more frequently?
>

It will be only once per startup.

Thanks,
Qiaowei