Re: [PATCH x86/urgent] bpf: emulate push insns for uprobe on x86

From: Thomas Gleixner
Date: Thu Nov 09 2017 - 01:53:49 EST


On Wed, 8 Nov 2017, Yonghong Song wrote:
> On 11/8/17 4:06 PM, David Miller wrote:
> > From: Yonghong Song <yhs@xxxxxx>
> > 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