From: Rashmica Gupta <rashmica.g@gmail.com>
To: David Hildenbrand <david@redhat.com>, Oscar Salvador <osalvador@suse.de>
Cc: akpm@linux-foundation.org, mhocko@suse.com,
dan.j.williams@intel.com, pasha.tatashin@soleen.com,
Jonathan.Cameron@huawei.com, anshuman.khandual@arm.com,
vbabka@suse.cz, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/5] Allocate memmap from hotadded memory
Date: Wed, 31 Jul 2019 12:21:16 +1000 [thread overview]
Message-ID: <7c49e493510ce04371d8d6cd6c436c347b1f8469.camel@gmail.com> (raw)
In-Reply-To: <b3fd1177-45ef-fd9e-78c8-d05138c647da@redhat.com>
On Mon, 2019-07-29 at 10:06 +0200, David Hildenbrand wrote:
> > > Of course, other interfaces might make sense.
> > >
> > > You can then start using these memory blocks and hinder them from
> > > getting onlined (as a safety net) via memory notifiers.
> > >
> > > That would at least avoid you having to call
> > > add_memory/remove_memory/offline_pages/device_online/modifying
> > > memblock
> > > states manually.
> >
> > I see what you're saying and that definitely sounds safer.
> >
> > We would still need to call remove_memory and add_memory from
> > memtrace
> > as
> > just offlining memory doesn't remove it from the linear page tables
> > (if
> > it's still in the page tables then hardware can prefetch it and if
> > hardware tracing is using it then the box checkstops).
>
> That prefetching part is interesting (and nasty as well). If we could
> at
> least get rid of the manual onlining/offlining, I would be able to
> sleep
> better at night ;) One step at a time.
>
What are your thoughts on adding remove to state_store in
drivers/base/memory.c? And an accompanying add? So then userspace could
do "echo remove > memory34/state"?
Then most of the memtrace code could be moved to a userspace tool. The
only bit that we would need to keep in the kernel is setting up debugfs
files in memtrace_init_debugfs.
next prev parent reply other threads:[~2019-07-31 2:21 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-25 7:52 [PATCH v2 0/5] Allocate memmap from hotadded memory Oscar Salvador
2019-06-25 7:52 ` [PATCH v2 1/5] drivers/base/memory: Remove unneeded check in remove_memory_block_devices Oscar Salvador
2019-06-25 8:01 ` David Hildenbrand
2019-06-25 8:03 ` David Hildenbrand
2019-06-25 8:09 ` Oscar Salvador
2019-06-25 8:27 ` David Hildenbrand
2019-06-25 7:52 ` [PATCH v2 2/5] mm,memory_hotplug: Introduce MHP_VMEMMAP_FLAGS Oscar Salvador
2019-06-25 8:31 ` David Hildenbrand
2019-07-24 20:11 ` Dan Williams
2019-07-24 21:36 ` osalvador
2019-07-25 9:27 ` Oscar Salvador
2019-07-25 9:30 ` David Hildenbrand
2019-07-25 9:40 ` Oscar Salvador
2019-07-25 10:04 ` David Hildenbrand
2019-07-25 10:13 ` Oscar Salvador
2019-07-25 10:15 ` David Hildenbrand
2019-06-25 7:52 ` [PATCH v2 3/5] mm,memory_hotplug: Introduce Vmemmap page helpers Oscar Salvador
2019-06-25 10:28 ` David Hildenbrand
2019-06-26 9:48 ` Oscar Salvador
2019-06-25 7:52 ` [PATCH v2 4/5] mm,memory_hotplug: allocate memmap from the added memory range for sparse-vmemmap Oscar Salvador
2019-06-25 8:49 ` David Hildenbrand
2019-06-26 8:13 ` Oscar Salvador
2019-06-26 8:15 ` David Hildenbrand
2019-06-26 8:17 ` Anshuman Khandual
2019-06-26 8:28 ` Oscar Salvador
2019-07-24 21:49 ` Dan Williams
2019-06-25 7:52 ` [PATCH v2 5/5] mm,memory_hotplug: Allow userspace to enable/disable vmemmap Oscar Salvador
2019-06-25 8:25 ` [PATCH v2 0/5] Allocate memmap from hotadded memory David Hildenbrand
2019-06-25 8:33 ` David Hildenbrand
2019-06-26 8:03 ` Oscar Salvador
2019-06-26 8:11 ` David Hildenbrand
2019-06-26 8:15 ` Oscar Salvador
2019-06-26 8:27 ` Oscar Salvador
2019-06-26 8:37 ` David Hildenbrand
2019-06-26 8:28 ` David Hildenbrand
2019-07-02 6:42 ` Rashmica Gupta
2019-07-02 7:48 ` Oscar Salvador
2019-07-02 8:52 ` Rashmica Gupta
2019-07-10 1:14 ` Rashmica Gupta
2019-07-31 12:08 ` Michal Hocko
2019-07-31 23:06 ` Rashmica Gupta
2019-08-01 7:17 ` Michal Hocko
2019-08-01 7:18 ` David Hildenbrand
2019-08-01 7:24 ` Michal Hocko
2019-08-01 7:26 ` David Hildenbrand
2019-08-01 7:31 ` David Hildenbrand
2019-08-01 7:39 ` Michal Hocko
2019-08-01 7:48 ` Michal Hocko
2019-08-01 9:18 ` David Hildenbrand
2019-08-01 7:34 ` Michal Hocko
2019-08-01 7:50 ` David Hildenbrand
2019-08-01 8:04 ` Michal Hocko
2019-07-16 12:28 ` David Hildenbrand
2019-07-29 5:42 ` Rashmica Gupta
2019-07-29 8:06 ` David Hildenbrand
2019-07-30 7:08 ` Rashmica Gupta
2019-07-31 2:21 ` Rashmica Gupta [this message]
2019-07-31 9:39 ` David Hildenbrand
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