tmp_suning_uos_patched/arch/powerpc/platforms
Jeremy Kerr b65fe0356b powerpc/spufs: Fix race for a free SPU
We currently have a race for a free SPE. With one thread doing a
spu_yield(), and another doing a spu_activate():

thread 1				thread 2
spu_yield(oldctx)			spu_activate(ctx)
  __spu_deactivate(oldctx)
  spu_unschedule(oldctx, spu)
  spu->alloc_state = SPU_FREE
					spu = spu_get_idle(ctx)
					    - searches for a SPE in
					      state SPU_FREE, gets
					      the context just
					      freed by thread 1
					spu_schedule(ctx, spu)
					  spu->alloc_state = SPU_USED
spu_schedule(newctx, spu)
  - assumes spu is still free
  - tries to schedule context on
    already-used spu

This change introduces a 'free_spu' flag to spu_unschedule, to indicate
whether or not the function should free the spu after descheduling the
context. We only set this flag if we're not going to re-schedule
another context on this SPU.

Add a comment to document this behaviour.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
2008-09-05 10:52:03 +10:00
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cell powerpc/spufs: Fix race for a free SPU 2008-09-05 10:52:03 +10:00
chrp
embedded6xx
iseries
maple
pasemi
powermac
prep
ps3
pseries
fsl_uli1575.c
Kconfig
Kconfig.cputype
Makefile