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  1. 02 Mar, 2009 3 commits
    • Jeremy Fitzhardinge's avatar
      x86: add forward decl for tss_struct · 2fb6b2a0
      Jeremy Fitzhardinge authored 
      Its the correct thing to do before using the struct in a prototype.
Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      2fb6b2a0
    • Jeremy Fitzhardinge's avatar
      x86: unify chunks of kernel/process*.c · 389d1fb1
      Jeremy Fitzhardinge authored 
      With x86-32 and -64 using the same mechanism for managing the
tss io permissions bitmap, large chunks of process*.c are
trivially unifyable, including:

 - exit_thread
 - flush_thread
 - __switch_to_xtra (along with tsc enable/disable)

and as bonus pickups:

 - sys_fork
 - sys_vfork

(Note: asmlinkage expands to empty on x86-64)
Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      389d1fb1
    • Jeremy Fitzhardinge's avatar
      x86-32: use non-lazy io bitmap context switching · db949bba
      Jeremy Fitzhardinge authored 
      Impact: remove 32-bit optimization to prepare unification

x86-32 and -64 differ in the way they context-switch tasks
with io permission bitmaps.  x86-64 simply copies the next
tasks io bitmap into place (if any) on context switch.  x86-32
invalidates the bitmap on context switch, so that the next
IO instruction will fault; at that point it installs the
appropriate IO bitmap.

This makes context switching IO-bitmap-using tasks a bit more
less expensive, at the cost of making the next IO instruction
slower due to the extra fault.  This tradeoff only makes sense
if IO-bitmap-using processes are relatively common, but they
don't actually use IO instructions very often.

However, in a typical desktop system, the only process likely
to be using IO bitmaps is the X server, and nothing at all on
a server.  Therefore the lazy context switch doesn't really win
all that much, and its just a gratuitious difference from
64-bit code.

This patch removes the lazy context switch, with a view to
unifying this code in a later change.
Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      db949bba
  3. 01 Mar, 2009 3 commits
  5. 28 Feb, 2009 23 commits
  7. 27 Feb, 2009 11 commits
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