Linux-mm Archive on lore.kernel.org
 help / color / Atom feed
From: Michal Hocko <mhocko@kernel.org>
To: Ran Wang <ran.wang_1@nxp.com>
Cc: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Vlastimil Babka <vbabka@suse.cz>,
	Andrew Morton <akpm@linux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	Reza Arbab <arbab@linux.vnet.ibm.com>,
	Yasuaki Ishimatsu <yasu.isimatu@gmail.com>,
	"qiuxishi@huawei.com" <qiuxishi@huawei.com>,
	Igor Mammedov <imammedo@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>, Leo Li <leoyang.li@nxp.com>,
	Xiaobo Xie <xiaobo.xie@nxp.com>
Subject: Re: [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages
Date: Mon, 13 Nov 2017 12:02:32 +0100
Message-ID: <20171113110232.ivd6l52y7j2q2iaq@dhcp22.suse.cz> (raw)
In-Reply-To: <AM3PR04MB14895AE080F9F21E98045D99F12B0@AM3PR04MB1489.eurprd04.prod.outlook.com>

On Mon 13-11-17 07:33:13, Ran Wang wrote:
> Hello Michal,
> 
> <snip>
> 
> > Date: Fri, 13 Oct 2017 14:00:12 +0200
> > 
> > From: Michal Hocko <mhocko@suse.com>
> > 
> > Michael has noticed that the memory offline tries to migrate kernel code
> > pages when doing  echo 0 > /sys/devices/system/memory/memory0/online
> > 
> > The current implementation will fail the operation after several failed page
> > migration attempts but we shouldn't even attempt to migrate that memory
> > and fail right away because this memory is clearly not migrateable. This will
> > become a real problem when we drop the retry loop counter resp. timeout.
> > 
> > The real problem is in has_unmovable_pages in fact. We should fail if there
> > are any non migrateable pages in the area. In orther to guarantee that
> > remove the migrate type checks because MIGRATE_MOVABLE is not
> > guaranteed to contain only migrateable pages. It is merely a heuristic.
> > Similarly MIGRATE_CMA does guarantee that the page allocator doesn't
> > allocate any non-migrateable pages from the block but CMA allocations
> > themselves are unlikely to migrateable. Therefore remove both checks.
> > 
> > Reported-by: Michael Ellerman <mpe@ellerman.id.au>
> > Signed-off-by: Michal Hocko <mhocko@suse.com>
> > Tested-by: Michael Ellerman <mpe@ellerman.id.au>
> > Acked-by: Vlastimil Babka <vbabka@suse.cz>
> > ---
> >  mm/page_alloc.c | 3 ---
> >  1 file changed, 3 deletions(-)
> > 
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c index
> > 3badcedf96a7..ad0294ab3e4f 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -7355,9 +7355,6 @@ bool has_unmovable_pages(struct zone *zone,
> > struct page *page, int count,
> >  	 */
> >  	if (zone_idx(zone) == ZONE_MOVABLE)
> >  		return false;
> > -	mt = get_pageblock_migratetype(page);
> > -	if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
> > -		return false;
> 
> This drop cause DWC3 USB controller fail on initialization with Layerscaper processors
> (such as LS1043A) as below:
> 
> [    2.701437] xhci-hcd xhci-hcd.0.auto: new USB bus registered, assigned bus number 1
> [    2.710949] cma: cma_alloc: alloc failed, req-size: 1 pages, ret: -16
> [    2.717411] xhci-hcd xhci-hcd.0.auto: can't setup: -12
> [    2.727940] xhci-hcd xhci-hcd.0.auto: USB bus 1 deregistered
> [    2.733607] xhci-hcd: probe of xhci-hcd.0.auto failed with error -12
> [    2.739978] xhci-hcd xhci-hcd.1.auto: xHCI Host Controller
> 
> And I notice that someone also reported to you that DWC2 got affected recently,
> so do you have the solution now?

Yes. It should be in linux-next. Have a look at the following email
thread: 
http://lkml.kernel.org/r/20171104082500.qvzbb2kw4suo6cgy@dhcp22.suse.cz

-- 
Michal Hocko
SUSE Labs

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  reply index

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <AM3PR04MB14892A9D6D2FBCE21B8C1F0FF12B0@AM3PR04MB1489.eurprd04.prod.outlook.com>
2017-11-13  7:33 ` Ran Wang
2017-11-13 11:02   ` Michal Hocko [this message]
2017-11-14  6:10     ` Ran Wang
2017-11-14  7:06       ` Michal Hocko
2017-11-14  7:45         ` Ran Wang
2017-10-13 11:58 [PATCH 1/2] mm, memory_hotplug: do not fail offlining too early Michal Hocko
2017-10-13 12:00 ` [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages Michal Hocko
2017-10-17 11:41   ` Michael Ellerman
2017-10-17 12:03     ` Michal Hocko
2017-10-17 13:02   ` Vlastimil Babka
2017-10-19  2:51   ` Joonsoo Kim
2017-10-19  7:15     ` Michal Hocko
2017-10-19  7:33       ` Joonsoo Kim
2017-10-19  8:20         ` Michal Hocko
2017-10-19 12:21           ` Michal Hocko
2017-10-20  2:13             ` Joonsoo Kim
2017-10-20  5:59               ` Michal Hocko
2017-10-20  6:50                 ` Joonsoo Kim
2017-10-20  7:02                   ` Michal Hocko
2017-10-23  5:23                     ` Joonsoo Kim
2017-10-23  8:10                       ` Michal Hocko
2017-10-24  4:44                         ` Joonsoo Kim
2017-10-24  7:44                           ` Michal Hocko
2017-10-24  8:12                           ` Vlastimil Babka
2017-10-24 12:25                             ` Michal Hocko
2017-10-26  2:47                             ` Joonsoo Kim
2017-10-26  7:41                               ` Michal Hocko
2017-10-20  7:22               ` Xishi Qiu
2017-10-20  8:17                 ` Michal Hocko
2017-10-23  5:26                   ` Joonsoo Kim
2017-10-26 13:04             ` Vlastimil Babka
2017-10-26 13:59             ` Michal Hocko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20171113110232.ivd6l52y7j2q2iaq@dhcp22.suse.cz \
    --to=mhocko@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=arbab@linux.vnet.ibm.com \
    --cc=imammedo@redhat.com \
    --cc=kamezawa.hiroyu@jp.fujitsu.com \
    --cc=leoyang.li@nxp.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mpe@ellerman.id.au \
    --cc=qiuxishi@huawei.com \
    --cc=ran.wang_1@nxp.com \
    --cc=vbabka@suse.cz \
    --cc=vkuznets@redhat.com \
    --cc=xiaobo.xie@nxp.com \
    --cc=yasu.isimatu@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-mm Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-mm/0 linux-mm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-mm linux-mm/ https://lore.kernel.org/linux-mm \
		linux-mm@kvack.org
	public-inbox-index linux-mm

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kvack.linux-mm


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git