linux-kernel - Non-linear Remap Vs. VM Cleanup: Performance Hit

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Date:	Tue, 24 Feb 2015 14:36:25 -0800
From:	"D. Cooper Stevenson" <cooper@...per.stevenson.name>
To:	linux-kernel@...r.kernel.org
Subject: Non-linear Remap Vs. VM Cleanup: Performance Hit

Hello All,

I read the Linus's release for RC1. One of his favorite features in the 
release are, "actually some vm cleanups, where this release is getting 
rid of the largely unused non-linear remapping code (replaced with just 
emulating it with lots of smaller mappings) and unifies the NUMA and 
PROTNONE handling for page tables."

I understand that non-linear page remapping is unused (and, presumably, 
reduces the code base size) but according to the remap_file_pages man 
page (http://man7.org/linux/man-pages/man2/remap_file_pages.2.html) 
non-linear system will be, "eventually be replaced by a slower in-kernel 
emulation."

Was this a change of necessity? What gives?

Also, would you please Cc: me on your replies as I am not a member of 
the mailing list?

Best Regards,

-Cooper
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