Impact: deadlock fix in ring_buffer_read_start
The ring_buffer_iter_reset was called from ring_buffer_read_start
where both grabbed the reader_lock.
This patch separates out the internals of ring_buffer_iter_reset
to its own function so that both APIs may grab the reader_lock.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: Cleanups on the boot tracer and ftrace
This patch bring some cleanups about the boot tracer headers. The
functions and structures of this tracer have nothing related to ftrace
and should have so their own header file.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: Restructure WARN_ONs in ring_buffer.c
The current WARN_ON macros in ring_buffer.c are quite ugly.
This patch cleans them up and uses a single RB_WARN_ON that returns
the value of the condition. This allows the caller to abort the
function if the condition is true.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: enable/disable ring buffer recording API added
Several kernel developers have requested that there be a way to stop
recording into the ring buffers with a simple switch that can also
be enabled from userspace. This patch addes a new kernel API to the
ring buffers called:
tracing_on()
tracing_off()
When tracing_off() is called, all ring buffers will not be able to record
into their buffers.
tracing_on() will enable the ring buffers again.
These two act like an on/off switch. That is, there is no counting of the
number of times tracing_off or tracing_on has been called.
A new file is added to the debugfs/tracing directory called
tracing_on
This allows for userspace applications to also flip the switch.
echo 0 > debugfs/tracing/tracing_on
disables the tracing.
echo 1 > /debugfs/tracing/tracing_on
enables it.
Note, this does not disable or enable any tracers. It only sets or clears
a flag that needs to be set in order for the ring buffers to write to
their buffers. It is a global flag, and affects all ring buffers.
The buffers start out with tracing_on enabled.
There are now three flags that control recording into the buffers:
tracing_on: which affects all ring buffer tracers.
buffer->record_disabled: which affects an allocated buffer, which may be set
if an anomaly is detected, and tracing is disabled.
cpu_buffer->record_disabled: which is set by tracing_stop() or if an
anomaly is detected. tracing_start can not reenable this if
an anomaly occurred.
The userspace debugfs/tracing/tracing_enabled is implemented with
tracing_stop() but the user space code can not enable it if the kernel
called tracing_stop().
Userspace can enable the tracing_on even if the kernel disabled it.
It is just a switch used to stop tracing if a condition was hit.
tracing_on is not for protecting critical areas in the kernel nor is
it for stopping tracing if an anomaly occurred. This is because userspace
can reenable it at any time.
Side effect: With this patch, I discovered a dead variable in ftrace.c
called tracing_on. This patch removes it.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
timers: handle HRTIMER_CB_IRQSAFE_UNLOCKED correctly from softirq context
nohz: disable tick_nohz_kick_tick() for now
irq: call __irq_enter() before calling the tick_idle_check
x86: HPET: enter hpet_interrupt_handler with interrupts disabled
x86: HPET: read from HPET_Tn_CMP() not HPET_T0_CMP
x86: HPET: convert WARN_ON to WARN_ON_ONCE
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: release buddies on yield
fix for account_group_exec_runtime(), make sure ->signal can't be freed under rq->lock
sched: clean up debug info
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ring-buffer: prevent infinite looping on time stamping
ftrace: disable tracing on resize
ftrace: fix breakage in bin_fmt results
ftrace: ftrace.txt version update
ftrace: update txt document
Impact: serialize reader accesses to individual CPU ring buffers
The code in the ring buffer expects only one reader at a time, but currently
it puts that requirement on the caller. This is not strong enough, and this
patch adds a "reader_lock" that serializes the access to the reader API
of the ring buffer.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://oss.sgi.com/xfs/xfs:
[XFS] XFS: Check for valid transaction headers in recovery
[XFS] handle memory allocation failures during log initialisation
[XFS] Account for allocated blocks when expanding directories
[XFS] Wait for all I/O on truncate to zero file size
[XFS] Fix use-after-free with log and quotas
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mfasheh/ocfs2: (21 commits)
ocfs2: Check search result in ocfs2_xattr_block_get()
ocfs2: fix printk related build warnings in xattr.c
ocfs2: truncate outstanding block after direct io failure
ocfs2/xattr: Proper hash collision handle in bucket division
ocfs2: return 0 in page_mkwrite to let VFS retry.
ocfs2: Set journal descriptor to NULL after journal shutdown
ocfs2: Fix check of return value of ocfs2_start_trans() in xattr.c.
ocfs2: Let inode be really deleted when ocfs2_mknod_locked() fails
ocfs2: Fix checking of return value of new_inode()
ocfs2: Fix check of return value of ocfs2_start_trans()
ocfs2: Fix some typos in xattr annotations.
ocfs2: Remove unused ocfs2_restore_xattr_block().
ocfs2: Don't repeat ocfs2_xattr_block_find()
ocfs2: Specify appropriate journal access for new xattr buckets.
ocfs2: Check errors from ocfs2_xattr_update_xattr_search()
ocfs2: Don't return -EFAULT from a corrupt xattr entry.
ocfs2: Check xattr block signatures properly.
ocfs2: add handler_map array bounds checking
ocfs2: remove duplicate definition in xattr
ocfs2: fix function declaration and definition in xattr
...
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-2.6: (35 commits)
V4L/DVB (9516): cx18: Move DVB buffer transfer handling from irq handler to work_queue
V4L/DVB (9557): gspca: Small changes for the sensor HV7131B in zc3xx.
V4L/DVB (9556): gspca: Bad init sequence for sensor HV7131B in zc3xx.
V4L/DVB (9549): gspca: Fix a typo in one of gspca chips name.
V4L/DVB (9515): cx18: Use correct Mailbox IRQ Ack values and misc IRQ handling cleanup
V4L/DVB (9493): kconfig patch
V4L/DVB (9527): af9015: fix compile warnings
V4L/DVB (9524): af9013: fix bug in status reading
V4L/DVB (9511): cx18: Mark CX18_CPU_DE_RELEASE_MDL as a slow API call
V4L/DVB (9510): cx18: Fix write retries for registers that always change - part 2.
V4L/DVB (9506): ivtv/cx18: fix test whether modules should be loaded or not.
V4L/DVB (9499): cx88-mpeg: final fix for analogue only compilation + de-alloc fix
V4L/DVB (9496): cx88-blackbird: bugfix: cx88-blackbird-mpeg-users
V4L/DVB (9495): cx88-blackbird: bugfix: cx88-blackbird-poll-fix
V4L/DVB (9494): anysee: initialize anysee_usb_mutex statically
V4L/DVB (9492): unplug oops from dvb_frontend_init...
V4L/DVB (9486): ivtv/ivtvfb: no longer experimental
V4L/DVB (9485): ivtv: remove incorrect V4L1 & tvaudio dependency
V4L/DVB (9482): Documentation, especially regarding audio and informational links
V4L/DVB (9475): cx18: Disable write retries for registers that always change - part 1.
...
* 'drm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6:
drm/i915: Move legacy breadcrumb out of the reserved status page area
drm/i915: Filter pci devices based on PCI_CLASS_DISPLAY_VGA
drm/radeon: map registers at load time
drm: Remove infrastructure for supporting i915's vblank swapping.
i915: Remove racy delayed vblank swap ioctl.
i915: Don't whine when pci_enable_msi() fails.
i915: Don't attempt to short-circuit object_wait_rendering by checking domains.
i915: Clean up sarea pointers on leavevt
i915: Save/restore MCHBAR_RENDER_STANDBY on GM965/GM45
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
dsa: fix master interface allmulti/promisc handling
dsa: fix skb->pkt_type when mac address of slave interface differs
net: fix setting of skb->tail in skb_recycle_check()
net: fix /proc/net/snmp as memory corruptor
mac80211: fix a buffer overrun in station debug code
netfilter: payload_len is be16, add size of struct rather than size of pointer
ipv6: fix ip6_mr_init error path
[4/4] dca: fixup initialization dependency
[3/4] I/OAT: fix async_tx.callback checking
[2/4] I/OAT: fix dma_pin_iovec_pages() error handling
[1/4] I/OAT: fix channel resources free for not allocated channels
ssb: Fix DMA-API compilation for non-PCI systems
SSB: hide empty sub menu
vlan: Fix typos in proc output string
[netdrvr] usb/hso: Cleanup rfkill error handling
sfc: Correct address of gPXE boot configuration in EEPROM
el3_common_init() should be __devinit, not __init
hso: rfkill type should be WWAN
mlx4_en: Start port error flow bug fix
af_key: mark policy as dead before destroying
fix:
arch/x86/kernel/ftrace.c: In function 'ftrace_return_to_handler':
arch/x86/kernel/ftrace.c:112: error: implicit declaration of function 'cpu_clock'
cpu_clock() is implicitly included via a number of ways, but its real
location is sched.h. (Build failure is triggerable if enough other
kernel components are turned off.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Clear buddies on yield, so that the buddy rules don't schedule them
despite them being placed right-most.
This fixed a performance regression with yield-happy binary JVMs.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Lin Ming <ming.m.lin@intel.com>
Ingo Molnar
Steven Rostedt
Frederic Weisbecker
Steven Rostedt
Linus Torvalds
Alan Cox
Peter Zijlstra