diff options
| author | Jeremy Fitzhardinge <[email protected]> | 2007-07-17 18:37:06 -0700 |
|---|---|---|
| committer | Jeremy Fitzhardinge <[email protected]> | 2007-07-18 08:47:44 -0700 |
| commit | 8b84ad942b534f8faeb34b68f0f7277ea375fed0 (patch) | |
| tree | 911472add5b9068a95a77215a70dac63edf6202e /include/linux | |
| parent | d66bf8fcf3fce058a1cd164a7c8ee6093fdf039c (diff) | |
xen: hack to prevent bad segment register reload
The hypervisor saves and restores the segment registers as part of the
state is saves while context switching. If, during a context switch,
the next process doesn't use the TLS segments, it invalidates the GDT
entry, causing the segment register reload to fault. This fault
effectively doubles the cost of a context switch.
This patch is a band-aid workaround which clears the usermode %gs
after it has been saved for the previous process, but before it gets
reloaded for the next, and it avoids having the hypervisor attempt to
erroneously reload it.
Signed-off-by: Jeremy Fitzhardinge <[email protected]>
Signed-off-by: Chris Wright <[email protected]>
Diffstat (limited to 'include/linux')
0 files changed, 0 insertions, 0 deletions