From: Jeremy Kerr Date: Mon, 18 Feb 2008 23:05:35 +0000 (+1100) Subject: [POWERPC] spufs: fix scheduler starvation by idle contexts X-Git-Tag: v2.6.25-rc3~102^2^2~1 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4ef110141b3e0758fe30d686417b5686b87eb25b;p=pandora-kernel.git [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 --- Reading git-diff-tree failed