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| author | Michael Neuling | 2010-05-10 22:28:26 +0200 |
|---|---|---|
| committer | Benjamin Herrenschmidt | 2010-05-21 09:31:11 +0200 |
| commit | d504bed676caad29a3dba3d3727298c560628f5c (patch) | |
| tree | ea7077d57b3e3018dc6be5b8687889283ba3f6e6 /arch/powerpc/kernel/machine_kexec_64.c | |
| parent | powerpc/pseries: Add hcall to read 4 ptes at a time in real mode (diff) | |
| download | kernel-qcow2-linux-d504bed676caad29a3dba3d3727298c560628f5c.tar.gz kernel-qcow2-linux-d504bed676caad29a3dba3d3727298c560628f5c.tar.xz kernel-qcow2-linux-d504bed676caad29a3dba3d3727298c560628f5c.zip | |
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 <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/machine_kexec_64.c')
0 files changed, 0 insertions, 0 deletions