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From: Ran Wang <ran.wang_1@nxp.com>
To: "linux-mm@kvack.org" <linux-mm@kvack.org>,
	Michal Hocko <mhocko@suse.com>
Cc: 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 07:33:13 +0000	[thread overview]
Message-ID: <AM3PR04MB14895AE080F9F21E98045D99F12B0@AM3PR04MB1489.eurprd04.prod.outlook.com> (raw)
In-Reply-To: <AM3PR04MB14892A9D6D2FBCE21B8C1F0FF12B0@AM3PR04MB1489.eurprd04.prod.outlook.com>

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?

Best regards

Ran
> 
>  	pfn = page_to_pfn(page);
>  	for (found = 0, iter = 0; iter < pageblock_nr_pages; iter++) {

       reply	other threads:[~2017-11-13  7:33 UTC|newest]

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 [this message]
2017-11-13 11:02   ` [PATCH 1/2] mm: drop migrate type checks from has_unmovable_pages Michal Hocko
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

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