linux-stable/arch/powerpc
sukadev@linux.vnet.ibm.com f34b6c72c3 powerpc/perf/hv-24x7: Use per-cpu page buffer
The 24x7 counters are continuously running and not updated on an
interrupt. So we record the event counts when stopping the event or
deleting it.

But to "read" a single counter in 24x7, we allocate a page and pass it
into the hypervisor (The HV returns the page full of counters from which
we extract the specific counter for this event).

We allocate a page using GFP_USER and when deleting the event, we end up
with the following warning because we are blocking in interrupt context.

  [  698.641709] BUG: scheduling while atomic: swapper/0/0/0x10010000

We could use GFP_ATOMIC but that could result in failures. Pre-allocate
a buffer so we don't have to allocate in interrupt context. Further as
Michael Ellerman suggested, use Per-CPU buffer so we only need to
allocate once per CPU.

Cc: stable@vger.kernel.org
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-12-12 16:05:18 +11:00
..
boot Merge remote-tracking branch 'scottwood/next' into next 2014-11-18 17:00:38 +11:00
configs powerpc/config: Enable memory driver 2014-11-17 19:36:42 -06:00
crypto
include powerpc/powernv: Return to cpu offline loop when finished in KVM guest 2014-12-08 13:16:31 +11:00
kernel powerpc: Secondary CPUs must set cpu_callin_map after setting active and online 2014-12-09 16:36:11 +11:00
kvm powerpc/powernv: Return to cpu offline loop when finished in KVM guest 2014-12-08 13:16:31 +11:00
lib powerpc: Remove more traces of bootmem 2014-11-19 21:41:51 +11:00
math-emu powerpc: Correct emulated mtfsf instruction 2014-04-07 10:33:11 +10:00
mm powerpc/mm: don't do tlbie for updatepp request with NO HPTE fault 2014-12-05 16:26:15 +11:00
net net: bpf: be friendly to kmemcheck 2014-09-09 16:58:56 -07:00
oprofile powerpc/oprofile: Disable pagefaults during user stack read 2014-12-02 14:10:08 +11:00
perf powerpc/perf/hv-24x7: Use per-cpu page buffer 2014-12-12 16:05:18 +11:00
platforms powerpc/powernv: Return to cpu offline loop when finished in KVM guest 2014-12-08 13:16:31 +11:00
sysdev powerpc: Remove more traces of bootmem 2014-11-19 21:41:51 +11:00
xmon powerpc/xmon: Cleanup the breakpoint flags 2014-12-02 14:23:04 +11:00
Kconfig Merge remote-tracking branch 'scottwood/next' into next 2014-11-18 17:00:38 +11:00
Kconfig.debug Patch queue for ppc - 2014-08-01 2014-08-05 09:58:11 +02:00
Makefile powerpc: Add POWER8 CPU selection 2014-09-25 23:14:49 +10:00
relocs_check.pl