From: Juergen Gross Date: Fri, 28 Nov 2014 10:53:59 +0000 (+0100) Subject: xen: Speed up set_phys_to_machine() by using read-only mappings X-Git-Tag: omap-for-v3.19/fixes-rc1~69^2^2~4 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2e917175e1ef147a527a9158b9f09773ec94c0bd;p=pandora-kernel.git xen: Speed up set_phys_to_machine() by using read-only mappings Instead of checking at each call of set_phys_to_machine() whether a new p2m page has to be allocated due to writing an entry in a large invalid or identity area, just map those areas read only and react to a page fault on write by allocating the new page. This change will make the common path with no allocation much faster as it only requires a single write of the new mfn instead of walking the address translation tables and checking for the special cases. Suggested-by: David Vrabel Signed-off-by: Juergen Gross Reviewed-by: David Vrabel Reviewed-by: Konrad Rzeszutek Wilk Signed-off-by: David Vrabel --- Reading git-diff-tree failed