linux/include
Peter Zijlstra 6ad4c18884 sched: Fix balance vs hotplug race
Since (e761b77: cpu hotplug, sched: Introduce cpu_active_map and redo
sched domain managment) we have cpu_active_mask which is suppose to rule
scheduler migration and load-balancing, except it never (fully) did.

The particular problem being solved here is a crash in try_to_wake_up()
where select_task_rq() ends up selecting an offline cpu because
select_task_rq_fair() trusts the sched_domain tree to reflect the
current state of affairs, similarly select_task_rq_rt() trusts the
root_domain.

However, the sched_domains are updated from CPU_DEAD, which is after the
cpu is taken offline and after stop_machine is done. Therefore it can
race perfectly well with code assuming the domains are right.

Cure this by building the domains from cpu_active_mask on
CPU_DOWN_PREPARE.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-06 21:10:56 +01:00
..
acpi ACPI: remove acpi_device_uid() and related stuff 2009-09-25 15:09:49 -04:00
asm-generic fcntl: rename F_OWNER_GID to F_OWNER_PGRP 2009-11-17 17:40:33 -08:00
crypto
drm Merge branch 'drm-next' of ../drm-next into drm-linus 2009-10-08 14:03:05 +10:00
keys
linux sched: Fix balance vs hotplug race 2009-12-06 21:10:56 +01:00
math-emu
media
mtd
net Merge branch 'security' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6 2009-11-30 16:47:16 -08:00
pcmcia Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2009-12-05 09:42:59 -08:00
rdma
rxrpc
scsi [SCSI] fix async scan add/remove race resulting in an oops 2009-11-26 09:43:39 -06:00
sound
trace Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-05 15:30:21 -08:00
video davinci-fb-frame-buffer-driver-for-ti-da8xx-omap-l1xx-v4 2009-09-23 07:39:51 -07:00
xen
Kbuild