From: "Williams, Dan J" <dan.j.williams@intel.com>
To: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"david@redhat.com" <david@redhat.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"Huang, Ying" <ying.huang@intel.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"richard.weiyang@gmail.com" <richard.weiyang@gmail.com>,
"hannes@cmpxchg.org" <hannes@cmpxchg.org>,
"minchan@kernel.org" <minchan@kernel.org>,
"mhocko@suse.com" <mhocko@suse.com>,
"mgorman@techsingularity.net" <mgorman@techsingularity.net>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH v2 1/3] mm/shuffle: don't move pages between zones and don't read garbage memmaps
Date: Sat, 20 Jun 2020 01:37:45 +0000 [thread overview]
Message-ID: <52c25f52d25d989b54e974f7c5c1c7de1bae674f.camel@intel.com> (raw)
In-Reply-To: <20200619125923.22602-2-david@redhat.com>
On Fri, 2020-06-19 at 14:59 +0200, David Hildenbrand wrote:
> Especially with memory hotplug, we can have offline sections (with a
> garbage memmap) and overlapping zones. We have to make sure to only
> touch initialized memmaps (online sections managed by the buddy) and
> that
> the zone matches, to not move pages between zones.
>
> To test if this can actually happen, I added a simple
> BUG_ON(page_zone(page_i) != page_zone(page_j));
> right before the swap. When hotplugging a 256M DIMM to a 4G x86-64 VM
> and
> onlining the first memory block "online_movable" and the second
> memory
> block "online_kernel", it will trigger the BUG, as both zones (NORMAL
> and MOVABLE) overlap.
>
> This might result in all kinds of weird situations (e.g., double
> allocations, list corruptions, unmovable allocations ending up in the
> movable zone).
>
> Fixes: e900a918b098 ("mm: shuffle initial free memory to improve
> memory-side-cache utilization")
> Acked-by: Michal Hocko <mhocko@suse.com>
> Cc: stable@vger.kernel.org # v5.2+
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Huang Ying <ying.huang@intel.com>
> Cc: Wei Yang <richard.weiyang@gmail.com>
> Cc: Mel Gorman <mgorman@techsingularity.net>
> Signed-off-by: David Hildenbrand <david@redhat.com>
Looks good to me.
Acked-by: Dan Williams <dan.j.williams@intel.com>
next prev parent reply other threads:[~2020-06-20 1:37 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-19 12:59 [PATCH v2 0/3] mm/shuffle: fix and cleanups David Hildenbrand
2020-06-19 12:59 ` [PATCH v2 1/3] mm/shuffle: don't move pages between zones and don't read garbage memmaps David Hildenbrand
2020-06-20 1:37 ` Williams, Dan J [this message]
2020-06-22 8:26 ` Wei Yang
2020-06-22 8:43 ` David Hildenbrand
2020-06-22 9:22 ` Wei Yang
2020-06-22 9:51 ` David Hildenbrand
2020-06-22 13:10 ` Wei Yang
2020-06-22 14:06 ` David Hildenbrand
2020-06-22 21:55 ` Wei Yang
2020-06-23 7:39 ` David Hildenbrand
2020-06-23 7:55 ` David Hildenbrand
2020-06-23 9:30 ` Wei Yang
2020-07-24 3:08 ` Andrew Morton
2020-07-24 5:45 ` Wei Yang
2020-07-24 8:20 ` David Hildenbrand
2020-06-22 14:11 ` David Hildenbrand
2020-06-19 12:59 ` [PATCH v2 2/3] mm/memory_hotplug: document why shuffle_zone() is relevant David Hildenbrand
2020-06-20 1:41 ` Dan Williams
2020-06-22 7:27 ` David Hildenbrand
2020-06-23 21:15 ` Dan Williams
2020-06-24 9:31 ` David Hildenbrand
2020-06-22 15:32 ` Michal Hocko
2020-06-19 12:59 ` [PATCH v2 3/3] mm/shuffle: remove dynamic reconfiguration David Hildenbrand
2020-06-20 1:49 ` Dan Williams
2020-06-22 7:33 ` David Hildenbrand
2020-06-22 8:37 ` Wei Yang
2020-06-23 22:18 ` Dan Williams
2020-06-22 15:37 ` Michal Hocko
2020-06-23 1:22 ` Wei Yang
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