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From: Thomas Gleixner <tglx@linutronix.de>
To: Yonghong Song <yhs@fb.com>
Cc: David Miller <davem@davemloft.net>,
	mingo@kernel.org, oleg@redhat.com, peterz@infradead.org,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	netdev@vger.kernel.org, ast@fb.com, kernel-team@fb.com
Subject: Re: [PATCH x86/urgent] bpf: emulate push insns for uprobe on x86
Date: Thu, 9 Nov 2017 07:53:31 +0100 (CET)	[thread overview]
Message-ID: <alpine.DEB.2.20.1711090749190.1962@nanos> (raw)
In-Reply-To: <526920a7-0329-cc2b-0cae-1af221a48aee@fb.com>

On Wed, 8 Nov 2017, Yonghong Song wrote:
> On 11/8/17 4:06 PM, David Miller wrote:
> > From: Yonghong Song <yhs@fb.com>
> > Date: Wed, 8 Nov 2017 13:37:12 -0800
> > 
> > > Uprobe is a tracing mechanism for userspace programs.
> > > Typical uprobe will incur overhead of two traps.
> > > First trap is caused by replaced trap insn, and
> > > the second trap is to execute the original displaced
> > > insn in user space.
> >   ...
> > 
> > I don't understand how this is bpf related, and if it is you don't
> > explain it well in the commit message.
> 
> Right. This is not related to bpf. Will remove the "bpf" from the subject line
> in the next revision.

The proper subject is something like:

    [PATCH] uprobes/x86: .......

which you can figure out by looking at the subsystem prefixes via

    git log arch/x86/kernel/uprobes.c

Note, that it says [PATCH} and nothing else. That patch is a nice
performance improvement, but certainly not x86/urgent material. x86/urgent
is for bug and regression fixes.

Thanks,

	tglx

  reply	other threads:[~2017-11-09  6:53 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-08 21:37 [PATCH x86/urgent] bpf: emulate push insns for uprobe on x86 Yonghong Song
2017-11-09  0:06 ` David Miller
2017-11-09  0:10   ` Yonghong Song
2017-11-09  6:53     ` Thomas Gleixner [this message]
2017-11-09  7:57       ` Yonghong Song

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