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From: Oscar Salvador <osalvador@suse.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	David Hildenbrand <david@redhat.com>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	Michal Hocko <mhocko@suse.com>, Linux MM <linux-mm@kvack.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] mm,memory_hotplug: Fix shrink_{zone,node}_span
Date: Wed, 17 Jul 2019 09:38:58 +0200
Message-ID: <20190717073853.GA22253@linux> (raw)
In-Reply-To: <CAPcyv4gp18-CRADqrqAbR0SnjKBoPaTyL_oaEyyNPJOeLybayg@mail.gmail.com>

On Tue, Jul 16, 2019 at 07:28:54PM -0700, Dan Williams wrote:
> This makes it more clear that the problem is with the "start_pfn ==
> pfn" check relative to subsections, but it does not clarify why it
> needs to clear pfn_valid() before calling shrink_zone_span().
> Sections were not invalidated prior to shrink_zone_span() in the
> pre-subsection implementation and it seems all we need is to keep the
> same semantic. I.e. skip the range that is currently being removed:

Yes, as I said in my reply to Aneesh, that is the other way I thought
when fixing it.
The reason I went this way is because it seemed more reasonable and
natural to me that pfn_valid() would just return the next active
sub-section.

I just though that we could leverage the fact that we can deactivate
a sub-section before scanning for the next one.

On a second thought, the changes do not outweight the case, being the first
fix enough and less intrusive, so I will send a v2 with that instead.


-- 
Oscar Salvador
SUSE L3


  reply index

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-15  8:15 [PATCH 0/2] Fixes for sub-section hotplug Oscar Salvador
2019-07-15  8:15 ` [PATCH 1/2] mm,sparse: Fix deactivate_section for early sections Oscar Salvador
2019-07-15 16:02   ` Aneesh Kumar K.V
2019-07-16  4:33   ` Dan Williams
2019-07-18 12:07   ` David Hildenbrand
2019-07-15  8:15 ` [PATCH 2/2] mm,memory_hotplug: Fix shrink_{zone,node}_span Oscar Salvador
2019-07-15 16:11   ` Aneesh Kumar K.V
2019-07-15 21:24     ` Oscar Salvador
2019-07-17  2:28       ` Dan Williams
2019-07-17  7:38         ` Oscar Salvador [this message]
2019-07-17  8:01           ` David Hildenbrand
2019-07-17  8:08             ` Oscar Salvador
2019-07-17  5:38       ` Aneesh Kumar K.V
2019-07-17  7:42         ` Oscar Salvador
2019-07-18 12:05   ` Oscar Salvador

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