Non-linear Remap Vs. VM Cleanup: Performance Hit

From: D. Cooper Stevenson
Date: Wed Feb 25 2015 - 01:36:34 EST


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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