From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yonghong Song Subject: Re: [PATCH x86/urgent] bpf: emulate push insns for uprobe on x86 Date: Wed, 8 Nov 2017 23:57:44 -0800 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="utf-8"; format=flowed Content-Transfer-Encoding: 7bit Cc: David Miller , , , , , , , , To: Thomas Gleixner Return-path: In-Reply-To: Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 11/8/17 10:53 PM, Thomas Gleixner wrote: > 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: ....... Thanks, Thomas, I will fix the subject etc. Previously, I added x86/urgent as the branch I did my test on top of it (similar to net-next). I will add that information in the comments and re-submit. > > 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 >