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linux-next/arch/powerpc
Jeremy Kerr 4ef110141b [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>
2008-02-19 10:12:02 +11:00
..
boot [POWERPC] Remove generated files on make clean 2008-02-14 22:11:02 +11:00
configs [POWERPC] 83xx: Update mpc83xx_defconfig 2008-02-05 23:48:06 -06:00
kernel [POWERPC] vdso_do_func_patch{32,64}() must be __init 2008-02-14 22:11:02 +11:00
lib [POWERPC] rheap: Changes config mechanism 2007-10-16 17:09:21 -06:00
math-emu [POWERPC] Fix carry bug in 128-bit unsigned integer adding 2008-01-23 19:34:21 -06:00
mm Merge branch 'for-2.6.25' of git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc 2008-02-08 09:31:42 -08:00
oprofile d_path: Make get_dcookie() use a struct path argument 2008-02-14 21:17:08 -08:00
platforms [POWERPC] spufs: fix scheduler starvation by idle contexts 2008-02-19 10:12:02 +11:00
sysdev [POWERPC] Add missing native dcr dcr_ind_lock spinlock 2008-02-06 21:02:56 -06:00
xmon [POWERPC] Make setjmp/longjmp code usable outside of xmon 2008-01-25 22:52:50 +11:00
.gitignore [POWERPC] Add files build to .gitignore 2006-12-04 20:41:29 +11:00
Kconfig [POWERPC] Remove unused CONFIG_WANT_DEVICE_TREE 2008-02-14 22:11:03 +11:00
Kconfig.debug [POWERPC] 4xx: Base support for 440GX Taishan eval board 2007-12-23 13:13:33 -06:00
Makefile [POWERPC] bootwrapper: Build multiple cuImages 2008-02-07 11:40:19 +11:00