Thread (17 messages) 17 messages, 4 authors, 2018-04-16

Re: [PATCH v3 2/4] mm/sparsemem: Defer the ms->section_mem_map clearing

From: Dave Hansen <hidden>
Date: 2018-04-09 16:02:35
Also in: lkml

On 04/07/2018 11:50 PM, Baoquan He wrote:
quoted
Should the " = 0" instead be clearing SECTION_MARKED_PRESENT or
something?  That would make it easier to match the code up with the code
that it is effectively undoing.
Not sure if I understand your question correctly. From memory_present(),
information encoded into ms->section_mem_map including numa node,
SECTION_IS_ONLINE and SECTION_MARKED_PRESENT. Not sure if it's OK to only
clear SECTION_MARKED_PRESENT.  People may wrongly check SECTION_IS_ONLINE
and do something on this memory section?
What is mean is that, instead of:

	
	ms->section_mem_map = 0;

we could literally do:

	ms->section_mem_map &= ~SECTION_MARKED_PRESENT;

That does the same thing in practice, but makes the _intent_ much more
clear.
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