From: Gavin Shan <shangw@linux.vnet.ibm.com>
To: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Gavin Shan <shangw@linux.vnet.ibm.com>,
linux-mm@kvack.org, rientjes@google.com, hannes@cmpxchg.org,
akpm@linux-foundation.org
Subject: Re: [PATCH 5/5] mm/sparse: return 0 if root mem_section exists
Date: Mon, 25 Jun 2012 09:09:06 +0800 [thread overview]
Message-ID: <20120625010906.GA4120@shangw> (raw)
In-Reply-To: <CAHGf_=o7CGkJevngH0UGn-FWaEEO1zTkFD+DjWDA_NDeHcVnnw@mail.gmail.com>
>> Function sparse_index_init() is used to setup memory section descriptors
>> dynamically. zero should be returned while mem_section[root] already has
>> been allocated.
>
>Why?
>
When CONFIG_SPARSEMEM_EXTREME is enabled, the memory section descriptors are
allocated dynamically and stored into "struct mem_section *mem_section[NR_SECTION_ROOTS]".
It's possible for multiple sections (e.g. 0, 1) sharing "mem_section[0]". When setup
the descriptor for section 0, the mem_section descriptor for section 1 should have
been created as well. So we needn't do same thing (actually duplicate) for section 1.
And the function returns "-EEXIST" in sparse_index_init() for section 1, which indicates
errors. Actually, here we need "0".
Does it make sense?
Thanks,
Gavin
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next prev parent reply other threads:[~2012-06-25 1:09 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-23 15:52 [PATCH 1/5] mm/sparse: check size of struct mm_section Gavin Shan
2012-06-23 15:52 ` [PATCH 2/5] mm/sparse: optimize sparse_index_alloc Gavin Shan
2012-06-25 15:30 ` Michal Hocko
2012-06-26 6:07 ` Gavin Shan
2012-06-26 7:04 ` Michal Hocko
2012-06-26 7:13 ` Gavin Shan
2012-06-23 15:52 ` [PATCH 3/5] mm/sparse: fix possible memory leak Gavin Shan
2012-06-25 15:48 ` Michal Hocko
2012-06-26 6:11 ` Gavin Shan
2012-06-26 7:14 ` Michal Hocko
2012-06-26 7:17 ` Gavin Shan
2012-06-23 15:52 ` [PATCH 4/5] mm/sparse: more check on mem_section number Gavin Shan
2012-06-26 16:15 ` Dave Hansen
2012-06-27 0:29 ` Gavin Shan
2012-06-23 15:52 ` [PATCH 5/5] mm/sparse: return 0 if root mem_section exists Gavin Shan
2012-06-24 19:18 ` KOSAKI Motohiro
2012-06-25 1:09 ` Gavin Shan [this message]
2012-06-25 15:39 ` Michal Hocko
2012-06-25 16:03 ` [PATCH 1/5] mm/sparse: check size of struct mm_section Michal Hocko
2012-06-25 16:35 ` Gavin Shan
2012-06-26 7:39 ` Michal Hocko
2012-06-26 7:48 ` Gavin Shan
2012-06-26 8:06 ` Michal Hocko
2012-06-26 8:24 ` Gavin Shan
2012-06-26 17:57 ` Michal Hocko
2012-06-27 3:01 ` Gavin Shan
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