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a5ccfee05a
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Anton Blanchard a5ccfee05a powerpc: Fix RCU idle and hcall tracing 
Tracepoints should not be called inside an rcu_idle_enter/rcu_idle_exit
region. Since pSeries calls H_CEDE in the idle loop, we were violating
this rule.

commit a7b152d534 (powerpc: Tell RCU about idle after hcall tracing)
tried to work around it by delaying the rcu_idle_enter until after we
called the hcall tracepoint, but there are a number of issues with it.

The hcall tracepoint trampoline code is called conditionally when the
tracepoint is enabled. If the tracepoint is not enabled we never call
rcu_idle_enter. The idle_uses_rcu check was also done at compile time
which breaks multiplatform builds.

The simple fix is to avoid tracing H_CEDE and rely on other tracepoints
and the hypervisor dispatch trace log to work out if we called H_CEDE.

This fixes a hang during boot on pSeries.

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2012-01-11 11:54:20 +11:00
..
boot Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2012-01-06 17:58:22 -08:00
configs Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2012-01-06 17:58:22 -08:00
include/asm Merge branch 'kvm-updates/3.3' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2012-01-10 09:57:11 -08:00
kernel powerpc: Fix RCU idle and hcall tracing 2012-01-11 11:54:20 +11:00
kvm Merge branch 'kvm-updates/3.3' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2012-01-10 09:57:11 -08:00
lib powerpc: POWER7 optimised copy_to_user/copy_from_user using VMX 2011-12-19 14:40:40 +11:00
math-emu powerpc/math_emu/efp: Look for errata handler when type mismatches 2011-10-06 23:36:47 -05:00
mm Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2012-01-08 13:21:22 -08:00
net net: filter: BPF 'JIT' compiler for PPC64 2011-07-21 12:38:32 -07:00
oprofile powerpc/oprofile: Handle events that raise an exception without overflowing 2011-05-26 13:38:57 +10:00
platforms powerpc: Fix RCU idle and hcall tracing 2012-01-11 11:54:20 +11:00
sysdev Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2012-01-08 12:19:57 -08:00
xmon powerpc/xmon: Fix #if typo for systems without MSR[RI] 2011-11-25 14:11:28 +11:00
Kconfig Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc 2012-01-06 17:58:22 -08:00
Kconfig.debug powerpc: Implement CONFIG_STRICT_DEVMEM 2011-11-28 11:42:08 +11:00
Makefile powerpc: Process dynamic relocations for kernel 2011-12-20 10:21:08 -05:00
relocs_check.pl powerpc: Process dynamic relocations for kernel 2011-12-20 10:21:08 -05:00