From: Wei Yang <richard.weiyang@gmail.com>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Wei Yang <richard.weiyang@gmail.com>,
linux-mm@kvack.org, akpm@linux-foundation.org
Subject: Re: [PATCH 1/2] mm, pageblock: make sure pageblock won't exceed mem_sectioin
Date: Wed, 5 Dec 2018 12:08:20 +0000 [thread overview]
Message-ID: <20181205120820.3gbhfvxgmclvj3wu@master> (raw)
In-Reply-To: <20181205111513.GA23260@techsingularity.net>
On Wed, Dec 05, 2018 at 11:15:13AM +0000, Mel Gorman wrote:
>On Wed, Dec 05, 2018 at 05:19:04PM +0800, Wei Yang wrote:
>> When SPARSEMEM is used, there is an indication that pageblock is not
>> allowed to exceed one mem_section. Current code doesn't have this
>> constrain explicitly.
>>
>> This patch adds this to make sure it won't.
>>
>> Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
>
>Is this even possible? This would imply that the section size is smaller
>than max order which would be quite a crazy selection for a sparesemem
>section size. A lot of assumptions on the validity of PFNs within a
>max-order boundary would be broken with such a section size. I'd be
>surprised if such a setup could even boot, let alone run.
pageblock_order has two definitions.
#define pageblock_order HUGETLB_PAGE_ORDER
#define pageblock_order (MAX_ORDER-1)
If CONFIG_HUGETLB_PAGE is not enabled, pageblock_order is related to
MAX_ORDER, which ensures it is smaller than section size.
If CONFIG_HUGETLB_PAGE is enabled, pageblock_order is not related to
MAX_ORDER. I don't see HUGETLB_PAGE_ORDER is ensured to be less than
section size. Maybe I missed it?
>
>--
>Mel Gorman
>SUSE Labs
--
Wei Yang
Help you, Help me
next prev parent reply other threads:[~2018-12-05 12:08 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-05 9:19 Wei Yang
2018-12-05 9:19 ` [PATCH 2/2] mm, page_alloc: cleanup usemap_size() when SPARSEMEM is not set Wei Yang
2018-12-07 9:58 ` Wei Yang
2018-12-05 11:15 ` [PATCH 1/2] mm, pageblock: make sure pageblock won't exceed mem_sectioin Mel Gorman
2018-12-05 12:08 ` Wei Yang [this message]
2018-12-05 15:37 ` Mel Gorman
2018-12-05 22:31 ` Wei Yang
2018-12-06 9:00 ` David Hildenbrand
2018-12-06 9:21 ` Wei Yang
2018-12-06 9:26 ` David Hildenbrand
2018-12-06 9:42 ` Wei Yang
2018-12-08 1:42 ` kbuild test robot
2018-12-09 12:03 ` Wei Yang
2018-12-13 2:26 ` Rong Chen
2018-12-13 3:08 ` Wei Yang
2018-12-13 5:02 ` Rong Chen
2018-12-13 7:28 ` Wei Yang
2018-12-09 13:58 ` kbuild test robot
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