linux/arch
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
..
alpha Introduce path_put() 2008-02-14 21:13:33 -08:00
arm Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm 2008-02-10 14:09:44 -08:00
avr32 ide: introduce HAVE_IDE 2008-02-09 10:46:40 +01:00
blackfin d_path: Make d_path() use a struct path 2008-02-14 21:17:09 -08:00
cris cris: import memset.c from newlib: fixes compile error with newer (pre4.3) gcc 2008-02-14 20:58:04 -08:00
frv xtime_lock vs update_process_times 2008-02-13 13:29:25 -08:00
h8300 ide: introduce HAVE_IDE 2008-02-09 10:46:40 +01:00
ia64 [IA64] Fix build for sim_defconfig 2008-02-11 13:23:46 -08:00
m32r ide: introduce HAVE_IDE 2008-02-09 10:46:40 +01:00
m68k ide: introduce HAVE_IDE 2008-02-09 10:46:40 +01:00
m68knommu m68knommu: fix profile timer 2008-02-14 20:58:05 -08:00
mips Introduce path_put() 2008-02-14 21:13:33 -08:00
mn10300 mn10300: add platform MTD support for the ASB2303 board 2008-02-08 09:22:30 -08:00
parisc Introduce path_put() 2008-02-14 21:13:33 -08:00
powerpc [POWERPC] spufs: fix scheduler starvation by idle contexts 2008-02-19 10:12:02 +11:00
ppc ide: introduce HAVE_IDE 2008-02-09 10:46:40 +01:00
s390 [S390] dynamic page tables. 2008-02-09 18:24:41 +01:00
sh sh: Fix multiple UTLB hit on UP SH-4. 2008-02-14 14:45:08 +09:00
sparc xtime_lock vs update_process_times 2008-02-13 13:29:25 -08:00
sparc64 Introduce path_put() 2008-02-14 21:13:33 -08:00
um Embed a struct path into struct nameidata instead of nd->{dentry,mnt} 2008-02-14 21:13:33 -08:00
v850 ide: introduce HAVE_IDE 2008-02-09 10:46:40 +01:00
x86 Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux-acpi-2.6 2008-02-14 21:29:46 -08:00
xtensa ide: introduce HAVE_IDE 2008-02-09 10:46:40 +01:00
.gitignore arch: Ignore arch/i386 and arch/x86_64 2008-01-19 21:29:39 -08:00
Kconfig Move Kconfig.instrumentation to arch/Kconfig and init/Kconfig 2008-02-03 08:58:08 +01:00