From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: [PATCH x86/urgent] bpf: emulate push insns for uprobe on x86 Date: Thu, 9 Nov 2017 07:53:31 +0100 (CET) Message-ID: References: <20171108213712.1232793-1-yhs@fb.com> <20171109.090647.824552877953564084.davem@davemloft.net> <526920a7-0329-cc2b-0cae-1af221a48aee@fb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: David Miller , 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 To: Yonghong Song Return-path: In-Reply-To: <526920a7-0329-cc2b-0cae-1af221a48aee@fb.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Wed, 8 Nov 2017, Yonghong Song wrote: > On 11/8/17 4:06 PM, David Miller wrote: > > From: Yonghong Song > > 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