From: David Hildenbrand <david@redhat.com>
To: Jerome Glisse <jglisse@redhat.com>, osalvador@techadventures.net
Cc: akpm@linux-foundation.org, mhocko@suse.com,
dan.j.williams@intel.com, pasha.tatashin@oracle.com,
yasu.isimatu@gmail.com, logang@deltatee.com,
dave.jiang@intel.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Oscar Salvador <osalvador@suse.de>
Subject: Re: [RFC PATCH 2/3] mm/memory_hotplug: Create __shrink_pages and move it to offline_pages
Date: Tue, 7 Aug 2018 16:54:57 +0200 [thread overview]
Message-ID: <a6e4e654-fc95-497f-16f3-8c1550cf03d6@redhat.com> (raw)
In-Reply-To: <20180807135221.GA3301@redhat.com>
On 07.08.2018 15:52, Jerome Glisse wrote:
> On Tue, Aug 07, 2018 at 03:37:56PM +0200, osalvador@techadventures.net wrote:
>> From: Oscar Salvador <osalvador@suse.de>
>
> [...]
>
>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>> index 9bd629944c91..e33555651e46 100644
>> --- a/mm/memory_hotplug.c
>> +++ b/mm/memory_hotplug.c
>
> [...]
>
>> /**
>> * __remove_pages() - remove sections of pages from a zone
>> - * @zone: zone from which pages need to be removed
>> + * @nid: node which pages belong to
>> * @phys_start_pfn: starting pageframe (must be aligned to start of a section)
>> * @nr_pages: number of pages to remove (must be multiple of section size)
>> * @altmap: alternative device page map or %NULL if default memmap is used
>> @@ -548,7 +557,7 @@ static int __remove_section(struct zone *zone, struct mem_section *ms,
>> * sure that pages are marked reserved and zones are adjust properly by
>> * calling offline_pages().
>> */
>> -int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
>> +int __remove_pages(int nid, unsigned long phys_start_pfn,
>> unsigned long nr_pages, struct vmem_altmap *altmap)
>> {
>> unsigned long i;
>> @@ -556,10 +565,9 @@ int __remove_pages(struct zone *zone, unsigned long phys_start_pfn,
>> int sections_to_remove, ret = 0;
>>
>> /* In the ZONE_DEVICE case device driver owns the memory region */
>> - if (is_dev_zone(zone)) {
>> - if (altmap)
>> - map_offset = vmem_altmap_offset(altmap);
>> - } else {
>> + if (altmap)
>> + map_offset = vmem_altmap_offset(altmap);
>> + else {
>
> This will break ZONE_DEVICE at least for HMM. While i think that
> altmap -> ZONE_DEVICE (ie altmap imply ZONE_DEVICE) the reverse
> is not true ie ZONE_DEVICE does not necessarily imply altmap. So
> with the above changes you change the expected behavior. You do
> need the zone to know if it is a ZONE_DEVICE. You could also lookup
> one of the struct page but my understanding is that this is what
> you want to avoid in the first place.
I wonder if we could instead forward from the callers whether we are
dealing with ZONE_DEVICE memory (is_device ...), at least that seems
feasible in hmm code. Not having looked at details yet.
>
> Cheers,
> Jérôme
>
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2018-08-07 14:55 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-07 13:37 [RFC PATCH 0/3] Do not touch pages in remove_memory path osalvador
2018-08-07 13:37 ` [RFC PATCH 1/3] mm/memory_hotplug: Add nid parameter to arch_remove_memory osalvador
2018-08-07 13:37 ` [RFC PATCH 2/3] mm/memory_hotplug: Create __shrink_pages and move it to offline_pages osalvador
2018-08-07 13:52 ` Jerome Glisse
2018-08-07 14:54 ` David Hildenbrand [this message]
2018-08-07 15:19 ` Jerome Glisse
2018-08-07 15:28 ` David Hildenbrand
2018-08-07 20:48 ` Oscar Salvador
2018-08-07 22:13 ` Jerome Glisse
2018-08-08 7:38 ` Oscar Salvador
2018-08-08 7:45 ` David Hildenbrand
2018-08-08 7:56 ` Oscar Salvador
2018-08-08 8:08 ` David Hildenbrand
2018-08-08 13:42 ` Oscar Salvador
2018-08-08 17:55 ` Jerome Glisse
2018-08-08 21:29 ` Oscar Salvador
2018-08-09 7:50 ` Oscar Salvador
2018-08-09 7:52 ` Oscar Salvador
2018-08-08 7:51 ` David Hildenbrand
2018-08-08 8:00 ` Oscar Salvador
2018-08-07 14:59 ` Michal Hocko
2018-08-07 15:18 ` Jerome Glisse
2018-08-08 6:47 ` Michal Hocko
2018-08-08 16:58 ` Jerome Glisse
2018-08-08 21:28 ` Oscar Salvador
2018-08-09 8:24 ` Michal Hocko
2018-08-09 14:27 ` Jerome Glisse
2018-08-09 15:09 ` Michal Hocko
2018-08-09 16:58 ` Jerome Glisse
2018-08-09 20:50 ` Oscar Salvador
2018-08-16 14:58 ` Oscar Salvador
2018-08-16 17:32 ` Jerome Glisse
2018-08-08 9:45 ` Oscar Salvador
2018-08-08 17:33 ` Jerome Glisse
2018-08-07 13:37 ` [RFC PATCH 3/3] mm/memory_hotplug: Refactor shrink_zone/pgdat_span osalvador
2018-08-07 14:16 ` [RFC PATCH 0/3] Do not touch pages in remove_memory path David Hildenbrand
2018-08-07 14:19 ` Oscar Salvador
2018-08-07 14:20 ` David Hildenbrand
2018-08-07 14:28 ` Oscar Salvador
2018-08-07 14:41 ` David Hildenbrand
2018-08-07 14:52 ` Oscar Salvador
2018-08-15 14:05 ` Pavel Tatashin
2018-08-15 14:32 ` Oscar Salvador
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