Re: [PATCH v3 07/15] mm/memory_hotplug: Introduce offline_and_remove_memory()

From: "Michael S. Tsirkin" <mst@redhat.com>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	virtio-dev@lists.oasis-open.org,
	virtualization@lists.linux-foundation.org, kvm@vger.kernel.org,
	Michal Hocko <mhocko@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.com>,
	Pankaj Gupta <pankaj.gupta.linux@gmail.com>,
	Oscar Salvador <osalvador@suse.com>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	Wei Yang <richard.weiyang@gmail.com>,
	Dan Williams <dan.j.williams@intel.com>, Qian Cai <cai@lca.pw>
Subject: Re: [PATCH v3 07/15] mm/memory_hotplug: Introduce offline_and_remove_memory()
Date: Thu, 7 May 2020 08:11:19 -0400	[thread overview]
Message-ID: <20200507080849-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <3bed2d1d-d94a-45ca-afe3-5e6ee660b0fc@redhat.com>

On Thu, May 07, 2020 at 01:37:30PM +0200, David Hildenbrand wrote:
> On 07.05.20 13:34, Michael S. Tsirkin wrote:
> > On Thu, May 07, 2020 at 01:33:23PM +0200, David Hildenbrand wrote:
> >>>> I get:
> >>>>
> >>>> error: sha1 information is lacking or useless (mm/memory_hotplug.c).
> >>>> error: could not build fake ancestor
> >>>>
> >>>> which version is this against? Pls post patches on top of some tag
> >>>> in Linus' tree if possible.
> >>>
> >>> As the cover states, latest linux-next. To be precise
> >>>
> >>> commit 6b43f715b6379433e8eb30aa9bcc99bd6a585f77 (tag: next-20200507,
> >>> next/master)
> >>> Author: Stephen Rothwell <sfr@canb.auug.org.au>
> >>> Date:   Thu May 7 18:11:31 2020 +1000
> >>>
> >>>     Add linux-next specific files for 20200507
> >>>
> >>
> >> The patches seem to apply cleanly on top of
> >>
> >> commit a811c1fa0a02c062555b54651065899437bacdbe (linus/master)
> >> Merge: b9388959ba50 16f8036086a9
> >> Author: Linus Torvalds <torvalds@linux-foundation.org>
> >> Date:   Wed May 6 20:53:22 2020 -0700
> >>
> >>     Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
> > 
> > Because you have the relevant hashes in your git tree not pruned yet.
> > Do a new clone and they won't apply.
> > 
> 
> Yeah, most probably, it knows how to merge. I'm used to sending all my
> -mm stuff based on -next, so this here is different.

Documentation/process/5.Posting.rst addresses this:

Patches must be prepared against a specific version of the kernel.  As a
general rule, a patch should be based on the current mainline as found in
Linus's git tree.  When basing on mainline, start with a well-known release
point - a stable or -rc release - rather than branching off the mainline at
an arbitrary spot.

It may become necessary to make versions against -mm, linux-next, or a
subsystem tree, though, to facilitate wider testing and review.  Depending
on the area of your patch and what is going on elsewhere, basing a patch
against these other trees can require a significant amount of work
resolving conflicts and dealing with API changes.

> I'll wait a bit and then send v4 based on latest linus/master, adding
> the two acks and reshuffling the MAINTAINERS patch. Thanks.
> 
> -- 
> Thanks,
> 
> David / dhildenb