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| author | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2009-04-24 09:26:50 +0200 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2009-05-09 00:55:24 +0200 |
| commit | a789ed5fb6d0256c4177c2cc27e06520ddbe4d4c (patch) | |
| tree | afdbb0c64c15ec522eae260949bfec02df2291b2 /drivers/xen/events.c | |
| parent | xen/x86-64: clean up warnings about IST-using traps (diff) | |
| download | linux-a789ed5fb6d0256c4177c2cc27e06520ddbe4d4c.tar.xz linux-a789ed5fb6d0256c4177c2cc27e06520ddbe4d4c.zip | |
xen: cache cr0 value to avoid trap'n'emulate for read_cr0
stts() is implemented in terms of read_cr0/write_cr0 to update the
state of the TS bit. This happens during context switch, and so
is fairly performance critical. Rather than falling back to
a trap-and-emulate native read_cr0, implement our own by caching
the last-written value from write_cr0 (the TS bit is the only one
we really care about).
Impact: optimise Xen context switches
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Diffstat (limited to 'drivers/xen/events.c')
0 files changed, 0 insertions, 0 deletions