Re: linux-next: manual merge of the tip tree with the net-next tree

From: Peter Zijlstra <peterz@infradead.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>,
	Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
	"H. Peter Anvin" <hpa@zytor.com>,
	David Miller <davem@davemloft.net>,
	Networking <netdev@vger.kernel.org>,
	Linux-Next Mailing List <linux-next@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Yonghong Song <yhs@fb.com>
Subject: Re: linux-next: manual merge of the tip tree with the net-next tree
Date: Wed, 1 Nov 2017 09:55:24 +0100	[thread overview]
Message-ID: <20171101085524.4dcxgaq7kawn37pq@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20171101082742.dteg337holmodzn2@gmail.com>

On Wed, Nov 01, 2017 at 09:27:43AM +0100, Ingo Molnar wrote:
> 
> * Peter Zijlstra <peterz@infradead.org> wrote:
> 
> > On Wed, Nov 01, 2017 at 06:15:54PM +1100, Stephen Rothwell wrote:
> > > Hi all,
> > > 
> > > Today's linux-next merge of the tip tree got a conflict in:
> > > 
> > >   kernel/trace/bpf_trace.c
> > > 
> > > between commits:
> > > 
> > >   97562633bcba ("bpf: perf event change needed for subsequent bpf helpers")
> > > and more changes ...
> > > 
> > > from the net-next tree and commit:
> > > 
> > >   7d9285e82db5 ("perf/bpf: Extend the perf_event_read_local() interface, a.k.a. "bpf: perf event change needed for subsequent bpf helpers"")
> > > 
> > > from the tip tree.
> > 
> > So those should be the exact same patch; except for Changelog and
> > subject. Code wise there shouldn't be a conflict.
> 
> So the problem is that then we have:
> 
>   0d3d73aac2ff ("perf/core: Rewrite event timekeeping")
> 
> which changes the code. This is a known conflict generation pattern: Git isn't 
> smart enough to sort out that (probably because it would make merges too 
> expensive) - and it's a bad flow in any case.

Hmm, I thought having that same base patch in both trees would allow it
to resolve that conflict. A well..