diff options
| author | Jeremy Kerr <jk@ozlabs.org> | 2008-02-19 10:05:35 +1100 |
|---|---|---|
| committer | Jeremy Kerr <jk@ozlabs.org> | 2008-02-19 10:12:02 +1100 |
| commit | 4ef110141b3e0758fe30d686417b5686b87eb25b (patch) | |
| tree | 388b52684d98bfc2e8ad443c391edb675eaf5360 /arch/powerpc/platforms/cell/spufs/run.c | |
| parent | 101142c37be8e5af9b847860219217e6b958c739 (diff) | |
[POWERPC] spufs: fix scheduler starvation by idle contexts
2.6.25 has a regression where we can starve the scheduler by creating
(N_SPES+1) contexts, then running them one at a time.
The final context will never be run, as the other contexts are loaded on
the SPEs, none of which are repoted as free (ie, spu->alloc_state !=
SPU_FREE), so spu_get_idle() doesn't give us a spu to run on. Because
all of the contexts are stopped, none are descheduled by the scheduler
tick, as spusched_tick returns if spu_stopped(ctx).
This change replaces the spu_stopped() check with checking for SCHED_IDLE
in ctx->policy. We set a context's policy to SCHED_IDLE when we're not
in spu_run(). We also favour SCHED_IDLE contexts when looking for contexts
to unbind, but leave their timeslice intact for later resumption.
This patch fixes the following test in the spufs-testsuite:
tests/20-scheduler/02-yield-starvation
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Diffstat (limited to 'arch/powerpc/platforms/cell/spufs/run.c')
| -rw-r--r-- | arch/powerpc/platforms/cell/spufs/run.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/run.c b/arch/powerpc/platforms/cell/spufs/run.c index fca22e18069..6221968c2a3 100644 --- a/arch/powerpc/platforms/cell/spufs/run.c +++ b/arch/powerpc/platforms/cell/spufs/run.c @@ -234,6 +234,7 @@ static int spu_run_fini(struct spu_context *ctx, u32 *npc, *npc = ctx->ops->npc_read(ctx); spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED); + ctx->policy = SCHED_IDLE; spu_release(ctx); if (signal_pending(current)) |