From: Michael Neuling Date: Mon, 10 May 2010 20:28:26 +0000 (+0000) Subject: powerpc/kexec: Speedup kexec hash PTE tear down X-Git-Tag: v2.6.35-rc1~450^2~9 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d504bed676caad29a3dba3d3727298c560628f5c;p=pandora-kernel.git powerpc/kexec: Speedup kexec hash PTE tear down Currently for kexec the PTE tear down on 1TB segment systems normally requires 3 hcalls for each PTE removal. On a machine with 32GB of memory it can take around a minute to remove all the PTEs. This optimises the path so that we only remove PTEs that are valid. It also uses the read 4 PTEs at once HCALL. For the common case where a PTEs is invalid in a 1TB segment, this turns the 3 HCALLs per PTE down to 1 HCALL per 4 PTEs. This gives an > 10x speedup in kexec times on PHYP, taking a 32GB machine from around 1 minute down to a few seconds. Signed-off-by: Michael Neuling Signed-off-by: Benjamin Herrenschmidt --- Reading git-diff-tree failed