Re: [PATCH 11/14] mm, memory_hotplug: do not associate hotadded memory to zones until online

From: Wei Yang <richard.weiyang@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, Mel Gorman <mgorman@suse.de>,
	Vlastimil Babka <vbabka@suse.cz>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Jerome Glisse <jglisse@redhat.com>,
	Reza Arbab <arbab@linux.vnet.ibm.com>,
	Yasuaki Ishimatsu <yasu.isimatu@gmail.com>,
	qiuxishi@huawei.com, Kani Toshimitsu <toshi.kani@hpe.com>,
	slaoub@gmail.com, Joonsoo Kim <js1304@gmail.com>,
	Andi Kleen <ak@linux.intel.com>,
	David Rientjes <rientjes@google.com>,
	Daniel Kiper <daniel.kiper@oracle.com>,
	Igor Mammedov <imammedo@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Dan Williams <dan.j.williams@intel.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>
Subject: Re: [PATCH 11/14] mm, memory_hotplug: do not associate hotadded memory to zones until online
Date: Fri, 16 Jun 2017 17:11:17 +0800	[thread overview]
Message-ID: <20170616091117.GA4716@WeideMacBook-Pro.local> (raw)
In-Reply-To: <20170616084555.GD30580@dhcp22.suse.cz>

[-- Attachment #1: Type: text/plain, Size: 2168 bytes --]

On Fri, Jun 16, 2017 at 10:45:55AM +0200, Michal Hocko wrote:
>On Fri 16-06-17 16:11:42, Wei Yang wrote:
>> Well, I love this patch a lot. We don't need to put the hotadd memory in one
>> zone and move it to another. This looks great!
>> 
>> On Mon, May 15, 2017 at 10:58:24AM +0200, Michal Hocko wrote:
>> >From: Michal Hocko <mhocko@suse.com>
>> >
>> [...]
>> +
>> >+void move_pfn_range_to_zone(struct zone *zone,
>> >+		unsigned long start_pfn, unsigned long nr_pages)
>> >+{
>> >+	struct pglist_data *pgdat = zone->zone_pgdat;
>> >+	int nid = pgdat->node_id;
>> >+	unsigned long flags;
>> >+	unsigned long i;
>> >+
>> >+	if (zone_is_empty(zone))
>> >+		init_currently_empty_zone(zone, start_pfn, nr_pages);
>> >+
>> >+	clear_zone_contiguous(zone);
>> >+
>> >+	/* TODO Huh pgdat is irqsave while zone is not. It used to be like that before */
>> >+	pgdat_resize_lock(pgdat, &flags);
>> >+	zone_span_writelock(zone);
>> >+	resize_zone_range(zone, start_pfn, nr_pages);
>> >+	zone_span_writeunlock(zone);
>> >+	resize_pgdat_range(pgdat, start_pfn, nr_pages);
>> >+	pgdat_resize_unlock(pgdat, &flags);
>> >+
>> >+	/*
>> >+	 * TODO now we have a visible range of pages which are not associated
>> >+	 * with their zone properly. Not nice but set_pfnblock_flags_mask
>> >+	 * expects the zone spans the pfn range. All the pages in the range
>> >+	 * are reserved so nobody should be touching them so we should be safe
>> >+	 */
>> >+	memmap_init_zone(nr_pages, nid, zone_idx(zone), start_pfn, MEMMAP_HOTPLUG);
>> >+	for (i = 0; i < nr_pages; i++) {
>> >+		unsigned long pfn = start_pfn + i;
>> >+		set_page_links(pfn_to_page(pfn), zone_idx(zone), nid, pfn);
>> > 	}
>> 
>> memmap_init_zone()->__init_single_page()->set_page_links()
>> 
>> Do I miss something that you call set_page_links() explicitly here?
>
>I guess you are right. Not sure why I've done this explicitly. I've most
>probably just missed that. Could you post a patch that removes the for
>loop.
>

Sure, I will come up with two patches based on you auto-latest branch.

>Thanks!
>-- 
>Michal Hocko
>SUSE Labs

-- 
Wei Yang
Help you, Help me

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 819 bytes --]