Revision 110a5c8b389407e1e859c43293179f9089671a60 authored by Linus Torvalds on 26 April 2012, 22:24:45 UTC, committed by Linus Torvalds on 26 April 2012, 22:24:45 UTC
Merge fixes from Andrew Morton: "13 fixes. The acerhdf patches aren't (really) fixes. But they've been stuck in my tree for up to two years, sent to Matthew multiple times and the developers are unhappy." * emailed from Andrew Morton <akpm@linux-foundation.org>: (13 patches) mm: fix NULL ptr dereference in move_pages mm: fix NULL ptr dereference in migrate_pages revert "proc: clear_refs: do not clear reserved pages" drivers/rtc/rtc-ds1307.c: fix BUG shown with lock debugging enabled arch/arm/mach-ux500/mbox-db5500.c: world-writable sysfs fifo file hugetlbfs: lockdep annotate root inode properly acerhdf: lowered default temp fanon/fanoff values acerhdf: add support for new hardware acerhdf: add support for Aspire 1410 BIOS v1.3314 fs/buffer.c: remove BUG() in possible but rare condition mm: fix up the vmscan stat in vmstat epoll: clear the tfile_check_list on -ELOOP mm/hugetlb: fix warning in alloc_huge_page/dequeue_huge_page_vma
events-power.txt
Subsystem Trace Points: power
The power tracing system captures events related to power transitions
within the kernel. Broadly speaking there are three major subheadings:
o Power state switch which reports events related to suspend (S-states),
cpuidle (C-states) and cpufreq (P-states)
o System clock related changes
o Power domains related changes and transitions
This document describes what each of the tracepoints is and why they
might be useful.
Cf. include/trace/events/power.h for the events definitions.
1. Power state switch events
============================
1.1 New trace API
-----------------
A 'cpu' event class gathers the CPU-related events: cpuidle and
cpufreq.
cpu_idle "state=%lu cpu_id=%lu"
cpu_frequency "state=%lu cpu_id=%lu"
A suspend event is used to indicate the system going in and out of the
suspend mode:
machine_suspend "state=%lu"
Note: the value of '-1' or '4294967295' for state means an exit from the current state,
i.e. trace_cpu_idle(4, smp_processor_id()) means that the system
enters the idle state 4, while trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id())
means that the system exits the previous idle state.
The event which has 'state=4294967295' in the trace is very important to the user
space tools which are using it to detect the end of the current state, and so to
correctly draw the states diagrams and to calculate accurate statistics etc.
1.2 DEPRECATED trace API
------------------------
A new Kconfig option CONFIG_EVENT_POWER_TRACING_DEPRECATED with the default value of
'y' has been created. This allows the legacy trace power API to be used conjointly
with the new trace API.
The Kconfig option, the old trace API (in include/trace/events/power.h) and the
old trace points will disappear in a future release (namely 2.6.41).
power_start "type=%lu state=%lu cpu_id=%lu"
power_frequency "type=%lu state=%lu cpu_id=%lu"
power_end "cpu_id=%lu"
The 'type' parameter takes one of those macros:
. POWER_NONE = 0,
. POWER_CSTATE = 1, /* C-State */
. POWER_PSTATE = 2, /* Frequency change or DVFS */
The 'state' parameter is set depending on the type:
. Target C-state for type=POWER_CSTATE,
. Target frequency for type=POWER_PSTATE,
power_end is used to indicate the exit of a state, corresponding to the latest
power_start event.
2. Clocks events
================
The clock events are used for clock enable/disable and for
clock rate change.
clock_enable "%s state=%lu cpu_id=%lu"
clock_disable "%s state=%lu cpu_id=%lu"
clock_set_rate "%s state=%lu cpu_id=%lu"
The first parameter gives the clock name (e.g. "gpio1_iclk").
The second parameter is '1' for enable, '0' for disable, the target
clock rate for set_rate.
3. Power domains events
=======================
The power domain events are used for power domains transitions
power_domain_target "%s state=%lu cpu_id=%lu"
The first parameter gives the power domain name (e.g. "mpu_pwrdm").
The second parameter is the power domain target state.
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