From: Tim Chen <tim.c.chen@linux.intel.com>
To: Andy Lutomirski <luto@kernel.org>, Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Arjan van de Ven <arjan@linux.intel.com>,
LKML <linux-kernel@vger.kernel.org>,
KarimAllah Ahmed <karahmed@amazon.de>,
Andrea Arcangeli <aarcange@redhat.com>,
Ashok Raj <ashok.raj@intel.com>,
Asit Mallick <asit.k.mallick@intel.com>,
Borislav Petkov <bp@suse.de>,
Dan Williams <dan.j.williams@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
David Woodhouse <dwmw@amazon.co.uk>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"H . Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Janakarajan Natarajan <Janakarajan.Natarajan@amd.com>,
Joerg Roedel <joro@8bytes.org>,
Jun Nakajima <jun.nakajima@intel.com>
Subject: Re: [RFC PATCH 1/2] x86/ibpb: Skip IBPB when we switch back to same user process
Date: Thu, 25 Jan 2018 15:07:11 -0800 [thread overview]
Message-ID: <f232ce18-3122-b045-be92-76fd61b195b5@linux.intel.com> (raw)
In-Reply-To: <CALCETrVnMT+hTL+U2s6Axhr3KmJY+L+czpkbmQd3qytB6FHnGw@mail.gmail.com>
On 01/25/2018 02:01 PM, Andy Lutomirski wrote:
> On Thu, Jan 25, 2018 at 1:57 PM, Andi Kleen <ak@linux.intel.com> wrote:
>> Andy Lutomirski <luto@kernel.org> writes:
>>>
>>> That being said, just stashing last_user_mm without any refcounting
>>> should be fine.
>>
>> If last_user_mm is freed and reallocated by a different process,
>> then that would miss the IPBP incorrectly.
>>
>
> Hmm, right. So ctx_id it is.
>
> --Andy
>
Thanks. Using ctx_id is a pretty clean approach. I will refresh
this patch and drop the second patch.
Tim
next prev parent reply other threads:[~2018-01-25 23:07 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-25 0:36 [RFC PATCH 1/2] x86/ibpb: Skip IBPB when we switch back to same user process Tim Chen
2018-01-25 0:36 ` [RFC PATCH 2/2] x86/ibpb: Prevent missed IBPB flush Tim Chen
2018-01-25 8:20 ` David Woodhouse
2018-01-25 16:56 ` Tim Chen
2018-01-25 8:58 ` [RFC PATCH 1/2] x86/ibpb: Skip IBPB when we switch back to same user process Peter Zijlstra
2018-01-25 9:22 ` Peter Zijlstra
2018-01-25 13:21 ` Arjan van de Ven
2018-01-25 13:50 ` Peter Zijlstra
2018-01-25 14:07 ` Arjan van de Ven
2018-01-25 16:41 ` Peter Zijlstra
2018-01-25 17:04 ` Andy Lutomirski
2018-01-25 18:18 ` Peter Zijlstra
2018-01-25 19:32 ` Tim Chen
2018-01-25 19:34 ` Arjan van de Ven
2018-01-25 19:45 ` Dave Hansen
2018-01-25 20:46 ` Peter Zijlstra
2018-01-25 21:04 ` Andy Lutomirski
2018-01-25 21:57 ` Andi Kleen
2018-01-25 22:01 ` Andy Lutomirski
2018-01-25 23:07 ` Tim Chen [this message]
2018-01-26 0:01 ` Peter Zijlstra
2018-01-25 17:24 ` Arjan van de Ven
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