Alan Cox [Tue, 14 Oct 2008 10:29:06 +0000 (11:29 +0100)]
8250: Fix lock warning (and possible crash)
Splitting the 8250 code back up to avoid a clash with the NR_IRQS removal
patch introduced a last minute bug. Put back the additional needed lines
for the old lock init
Signed-off-by: Alan Cox <alan@redhat.com>
[ Ingo also reports that this can cause a spontaneous reboot crash with
certain configs, and sends in an identical patch ] Tested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Brownell [Tue, 14 Oct 2008 15:30:06 +0000 (17:30 +0200)]
i2c: Do earlier driver model init
Move I2C driver model init earlier in the boot sequence.
This avoids oopsing in statically linked systems when some
subsystems register I2C drivers in subsys_initcall() code,
but those subsystems are linked (and initialized) before I2C.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Jean Delvare [Tue, 14 Oct 2008 15:30:06 +0000 (17:30 +0200)]
i2c: Only build Tyan SMBus mux drivers on x86
The two Tyan SMBus mux drivers (i2c-amd756-s4882 and i2c-nforce2-s4985)
are only useful on specific x86 motherboards, so there is no point in
letting them be built on other architectures.
David Brownell [Tue, 14 Oct 2008 15:30:05 +0000 (17:30 +0200)]
i2c: Guard against oopses from bad init sequences
Guard I2C against oopsing because of init sequence problems, by
verifying that i2c_init() has been called before calling any
routines that rely on that initialization. This specific test
just requires that bus_register(&i2c_bus_type) was called.
Examples of this kind of oopsing come from subystems and drivers
which register I2C drivers in their subsys_initcall code but
which are statically linked before I2C by drivers/Makefile.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Jean Delvare [Tue, 14 Oct 2008 15:30:04 +0000 (17:30 +0200)]
i2c-parport-light: Don't register a platform device resource
The i2c-parport-light driver isn't a real platform driver, so it
should not instantiate platform devices with resources. The resource
management system can't cope with colliding resources, and we are
likely to create such a colliding resource.
So, better just try to grab the I/O ports we need right at module
initialization time, and bail out if we can't. It has the added
benefit that the module will no longer load if it isn't going to work,
which is definitely more user-friendly.
Jean Delvare [Tue, 14 Oct 2008 15:30:04 +0000 (17:30 +0200)]
hwmon: (dme1737) Convert to a new-style i2c driver
The new-style dme1737 driver implements the optional detect() callback
to cover the use cases of the legacy driver. I don't actually expect
any new-style device for that driver, but as the old i2c API is going
away soon, we have to switch to the new one.
Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: Juerg Haefliger <juergh@gmail.com>
Jean Delvare [Tue, 14 Oct 2008 15:30:04 +0000 (17:30 +0200)]
hwmon: (dme1737) Be less i2c-centric
The dme1737 driver support both LPC (ISA) and SMBus devices. At the
moment it's rather i2c-centric, and LPC variants use a fake i2c_client
for some operations.
In a near future, i2c_client will be allocated by i2c-core rather than
by the device drivers, so non-i2c drivers will not have one. As a
preparation step, change the driver code to no longer assume that
an i2c_client structure is always available. No functional change.
Signed-off-by: Jean Delvare <khali@linux-fr.org> Cc: Juerg Haefliger <juergh@gmail.com>
Marek Vasut [Tue, 14 Oct 2008 15:30:04 +0000 (17:30 +0200)]
i2c/tps65010: Vibrator hookup to gpiolib
All the tps6501{0,1,2,3,4} chips have a signal for hooking up with
a vibrator (for non-auditory cell phone "ring") ... expose that as
one more (output-only) GPIO.
[ dbrownell@users.sourceforge.net: comments; list tps65014 too ]
Signed-off-by: Marek Vasut <marek.vasut@gmail.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Paul Mundt [Tue, 14 Oct 2008 15:30:03 +0000 (17:30 +0200)]
i2c: Renesas Highlander FPGA SMBus support
This adds support for the SMBus adapter found in the various FPGAs on
the Renesas Highlander platforms. Particularly the R0P7780LC0011RL and
R0P7785LC0011RL FPGAs.
Functionality is fairly restricted, in that only byte and block data
transfers are supported. Normal/fast mode and IRQ/polling are also
supported. Primarily used for various RTCs and thermal sensors.
Signed-off-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Jean Delvare <khali@linux-fr.org>
Rene Herman [Tue, 14 Oct 2008 15:30:03 +0000 (17:30 +0200)]
i2c-pca-isa: Don't grab arbitrary resources
Grabbing ISA bus resources without anything or anyone telling us we
should can break boot on randconfig/allyesconfig builds by keeping
resources that are in fact owned by different hardware busy and does
as reported by Ingo Molnar.
Generally it's also dangerous to just poke at random I/O ports and
especially those in the range where other old easily confused ISA
hardware might live.
For this specialized I2C bus driver, insist that the user specifies
the resources before grabbing them.
Oleg Nesterov [Sun, 8 Jun 2008 17:20:43 +0000 (21:20 +0400)]
do_generic_file_read: s/EINTR/EIO/ if lock_page_killable() fails
If lock_page_killable() fails because the task was killed by SIGKILL or
any other fatal signal, do_generic_file_read() returns -EIO.
This seems to be OK, because in fact the userspace won't see this error,
the task will dequeue SIGKILL and exit.
However, /sbin/init is different, it will dequeue SIGKILL, ignore it, and
return to the user-space with the bogus -EIO.
Change the code to return the error code from lock_page_killable(), -EINTR.
This doesn't fix the bug, but perhaps makes sense anyway. Imho, with this
change the code looks a bit more logical, and the "good" init should handle
the spurious EINTR or short read.
Afaics we can also change lock_page_killable() to return -ERESTARTNOINTR,
but this can't prevent the short reads.
Ext4 was the only user of range_cont writeback mode and ext4 switched
to a different method. So remove the range_cont mode which is not used
in the kernel.
Richard Genoud [Sun, 12 Oct 2008 06:42:28 +0000 (08:42 +0200)]
[MTD] [NAND] Bug on atmel_nand HW ECC : OOB info not correctly written
The functions that write the OOB info (on hardware ECC only) use the
HW_SYNDROME method.
This is not correct : the start position is "pos = eccsize + chunk" and
should be eccsize. So, the standard (nand_write_oob_std) function should
be used. This patch corrects this by using NAND_ECC_HW instead of
NAND_ECC_HW_SYNDROME.
This has only been tested on small pages nand flash.
(if anyone can test it on large pages that would be great).
kernel version : 2.6.27-rc2 (current git mtd-2.6)
Signed-off-by: Richard Genoud <richard.genoud@gmail.com> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Marc Zyngier [Tue, 14 Oct 2008 08:57:05 +0000 (09:57 +0100)]
ALSA: Fix pxa2xx-ac97-lib.c compilation
The last ALSA merge broke pxa2xx-ac97-lib.c, as it brought back
references to cpu_is_pxa21x that Eric Miao removed in commit 0ffcbfd54ea81ca24c0749f55ca4fcf3e2bdc23e:
[ARM] pxa: make cpu_is_pxa2* macros more consistent
This patch gets rid of those references, and only keeps cpu_is_pxa25x().
Signed-off-by: Marc Zyngier <maz@misterjones.org> Acked-by: Eric Miao <eric.miao@marvell.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Takashi Iwai <tiwai@suse.de>
tracing/fastboot: fix bootgraph.pl initcall name regexp
The regexp used to match the start and the end of an initcall
are matching only on [a-zA-Z\_]. This rules out initcalls with
a number in them. This patch is fixing that.
Arjan van de Ven [Sun, 14 Sep 2008 22:30:52 +0000 (15:30 -0700)]
tracing/fastboot: fix issues and improve output of bootgraph.pl
David Sanders reported some issues with bootgraph.pl's display
of his sytems bootup; this commit fixes these by scaling the graph
not from 0 - end time but from the first initcall to the end time;
the minimum display size etc also now need to scale with this, as does
the axis display.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Create tracepoint_synchronize_unregister() which must be called before the end
of exit() to make sure every probe callers have exited the non preemptible
section and thus are not executing the probe code anymore.
This is not friendly to disassemblers because an odd number of 0x00s
ends in the middle of an instruction boundary. This changes the 0x00s
to 1-byte NOPs (0x90).
Signed-off-by: Anders Kaseorg <andersk@mit.edu> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Use a #define for synchronize marker unregister to fix include dependencies.
Fixes the slab circular inclusion which triggers when slab.git is combined
with tracing.git, where rcupdate includes slab, which includes markers
which includes rcupdate.
Tim Bird [Thu, 9 Oct 2008 22:23:05 +0000 (15:23 -0700)]
tracing/fastboot: add better resolution to initcall debug/tracing
Change the time resolution for initcall_debug to microseconds, from
milliseconds. This is handy to determine which initcalls you want to work
on for faster booting.
One one of my test machines, over 90% of the initcalls are less than a
millisecond and (without this patch) these are all reported as 0 msecs.
Working on the 900 us ones is more important than the 4 us ones.
With 'quiet' on the kernel command line, this adds no significant overhead
to kernel boot time.
Signed-off-by: Tim Bird <tim.bird@am.sony.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
[based on a patch by Philippe Reynes <tremyfr@yahoo.fr>] Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Steven Rostedt [Sat, 4 Oct 2008 06:00:59 +0000 (02:00 -0400)]
ring-buffer: make reentrant
This patch replaces the local_irq_save/restore with preempt_disable/
enable. This allows for interrupts to enter while recording.
To write to the ring buffer, you must reserve data, and then
commit it. During this time, an interrupt may call a trace function
that will also record into the buffer before the commit is made.
The interrupt will reserve its entry after the first entry, even
though the first entry did not finish yet.
The time stamp delta of the interrupt entry will be zero, since
in the view of the trace, the interrupt happened during the
first field anyway.
Locking still takes place when the tail/write moves from one page
to the next. The reader always takes the locks.
A new page pointer is added, called the commit. The write/tail will
always point to the end of all entries. The commit field will
point to the last committed entry. Only this commit entry may
update the write time stamp.
The reader can only go up to the commit. It cannot go past it.
If a lot of interrupts come in during a commit that fills up the
buffer, and it happens to make it all the way around the buffer
back to the commit, then a warning is printed and new events will
be dropped.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Steven Rostedt [Sat, 4 Oct 2008 06:00:58 +0000 (02:00 -0400)]
ring-buffer: move page indexes into page headers
Remove the global head and tail indexes and move them into the
page header. Each page will now keep track of where the last
write and read was made. We also rename the head and tail to read
and write for better clarification.
This patch is needed for future enhancements to move the ring buffer
to a lockless solution.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Steven Rostedt [Thu, 2 Oct 2008 23:18:09 +0000 (19:18 -0400)]
ring_buffer: map to cpu not page
My original patch had a compile bug when NUMA was configured. I
referenced cpu when it should have been cpu_buffer->cpu.
Ingo quickly fixed this bug by replacing cpu with 'i' because that
was the loop counter. Unfortunately, the 'i' was the counter of
pages, not CPUs. This caused a crash when the number of pages allocated
for the buffers exceeded the number of pages, which would usually
be the case.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
tracing/fastboot: get the initcall name before it disappears
After some initcall traces, some initcall names may be inconsistent.
That's because these functions will disappear from the .init section
and also their name from the symbols table.
So we have to copy the name of the function in a buffer large enough
during the trace appending. It is not costly for the ring_buffer because
the number of initcall entries is commonly not really large.
tracing/fastboot: change the printing of boot tracer according to bootgraph.pl
Change the boot tracer printing to make it parsable for
the scripts/bootgraph.pl script.
We have now to output two lines for each initcall, according to the
printk in do_one_initcall() in init/main.c
We need now the call's time and the return's time.
Ingo Molnar [Thu, 2 Oct 2008 09:04:14 +0000 (11:04 +0200)]
ring-buffer: fix build error
fix:
kernel/trace/ring_buffer.c: In function ‘rb_allocate_pages’:
kernel/trace/ring_buffer.c:235: error: ‘cpu’ undeclared (first use in this function)
kernel/trace/ring_buffer.c:235: error: (Each undeclared identifier is reported only once
kernel/trace/ring_buffer.c:235: error: for each function it appears in.)
Steven Rostedt [Wed, 1 Oct 2008 17:14:09 +0000 (13:14 -0400)]
ftrace: preempt disable over interrupt disable
With the new ring buffer infrastructure in ftrace, I'm trying to make
ftrace a little more light weight.
This patch converts a lot of the local_irq_save/restore into
preempt_disable/enable. The original preempt count in a lot of cases
has to be sent in as a parameter so that it can be recorded correctly.
Some places were recording it incorrectly before anyway.
This is also laying the ground work to make ftrace a little bit
more reentrant, and remove all locking. The function tracers must
still protect from reentrancy.
Note: All the function tracers must be careful when using preempt_disable.
It must do the following:
resched = need_resched();
preempt_disable_notrace();
[...]
if (resched)
preempt_enable_no_resched_notrace();
else
preempt_enable_notrace();
The reason is that if this function traces schedule() itself, the
preempt_enable_notrace() will cause a schedule, which will lead
us into a recursive failure.
If we needed to reschedule before calling preempt_disable, we
should have already scheduled. Since we did not, this is most
likely that we should not and are probably inside a schedule
function.
If resched was not set, we still need to catch the need resched
flag being set when preemption was off and the if case at the
end will catch that for us.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Steven Rostedt [Wed, 1 Oct 2008 15:14:54 +0000 (11:14 -0400)]
ring_buffer: allocate buffer page pointer
The current method of overlaying the page frame as the buffer page pointer
can be very dangerous and limits our ability to do other things with
a page from the buffer, like send it off to disk.
This patch allocates the buffer_page instead of overlaying the page's
page frame. The use of the buffer_page has hardly changed due to this.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Steven Rostedt [Wed, 1 Oct 2008 14:52:51 +0000 (10:52 -0400)]
ftrace: type cast filter+verifier
The mmiotrace map had a bug that would typecast the entry from
the trace to the wrong type. That is a known danger of C typecasts,
there's absolutely zero checking done on them.
Help that problem a bit by using a GCC extension to implement a
type filter that restricts the types that a trace record can be
cast into, and by adding a dynamic check (in debug mode) to verify
the type of the entry.
This patch adds a macro to assign all entries of ftrace using the type
of the variable and checking the entry id. The typecasts are now done
in the macro for only those types that it knows about, which should
be all the types that are allowed to be read from the tracer.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Steven Rostedt [Wed, 1 Oct 2008 04:29:53 +0000 (00:29 -0400)]
ring_buffer: implement new locking
The old "lock always" scheme had issues with lockdep, and was not very
efficient anyways.
This patch does a new design to be partially lockless on writes.
Writes will add new entries to the per cpu pages by simply disabling
interrupts. When a write needs to go to another page than it will
grab the lock.
A new "read page" has been added so that the reader can pull out a page
from the ring buffer to read without worrying about the writer writing over
it. This allows us to not take the lock for all reads. The lock is
now only taken when a read needs to go to a new page.
This is far from lockless, and interrupts still need to be disabled,
but it is a step towards a more lockless solution, and it also
solves a lot of the issues that were noticed by the first conversion
of ftrace to the ring buffers.
Note: the ring_buffer_{un}lock API has been removed.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
tracing/ftrace: change the type of the print_line callback
We need a kind of disambiguation when a print_line callback
returns 0.
_There is not enough space to print all the entry.
Please flush the seq and retry.
_I can't handle this type of entry
This patch changes the type of this callback for better information.
Also some changes have been made in this V2.
_ Only relay to default functions after the print_line callback fails.
_ This patch doesn't fix the issue with the broken pipe (see patch 2/4 for that)
Some things are still in discussion:
_ Find better names for the enum print_line_t values
_ Change the type of print_trace_line into boolean.
Steven Rostedt [Tue, 30 Sep 2008 03:02:42 +0000 (23:02 -0400)]
ftrace: take advantage of variable length entries
Now that the underlining ring buffer for ftrace now hold variable length
entries, we can take advantage of this by only storing the size of the
actual event into the buffer. This happens to increase the number of
entries in the buffer dramatically.
We can also get rid of the "trace_cont" operation, but I'm keeping that
until we have no more users. Some of the ftrace tracers can now change
their code to adapt to this new feature.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Steven Rostedt [Tue, 30 Sep 2008 03:02:39 +0000 (23:02 -0400)]
ring_buffer: add paranoid check for buffer page
If for some strange reason the buffer_page gets bigger, or the page struct
gets smaller, I want to know this ASAP. The best way is to not let the
kernel compile.
This patch adds code to test the size of the struct buffer_page against the
page struct and will cause compile issues if the buffer_page ever gets bigger
than the page struct.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
The minimum size of an event is 8 bytes. All events are 4 byte
aligned inside the buffer.
There are 4 types (all internal use for the ring buffer, only
the data type is exported to the interface users).
RINGBUF_TYPE_PADDING: this type is used to note extra space at the end
of a buffer page.
RINGBUF_TYPE_TIME_EXTENT: This type is used when the time between events
is greater than the 27 bit delta can hold. We add another
32 bits, and record that in its own event (8 byte size).
RINGBUF_TYPE_TIME_STAMP: (Not implemented yet). This will hold data to
help keep the buffer timestamps in sync.
RINGBUF_TYPE_DATA: The event actually holds user data.
The "len" field is only three bits. Since the data must be
4 byte aligned, this field is shifted left by 2, giving a
max length of 28 bytes. If the data load is greater than 28
bytes, the first array field holds the full length of the
data load and the len field is set to zero.
Example, data size of 7 bytes:
type = RINGBUF_TYPE_DATA
len = 2
time_delta: <time-stamp> - <prev_event-time-stamp>
array[0..1]: <7 bytes of data> <1 byte empty>
This event is saved in 12 bytes of the buffer.
An event with 82 bytes of data:
type = RINGBUF_TYPE_DATA
len = 0
time_delta: <time-stamp> - <prev_event-time-stamp>
array[0]: 84 (Note the alignment)
array[1..14]: <82 bytes of data> <2 bytes empty>
The above event is saved in 92 bytes (if my math is correct).
82 bytes of data, 2 bytes empty, 4 byte header, 4 byte length.
Do not reference the above event struct directly. Use the following
functions to gain access to the event table, since the
ring_buffer_event structure may change in the future.
ring_buffer_event_length(event): get the length of the event.
This is the size of the memory used to record this
event, and not the size of the data pay load.
ring_buffer_time_delta(event): get the time delta of the event
This returns the delta time stamp since the last event.
Note: Even though this is in the header, there should
be no reason to access this directly, accept
for debugging.
ring_buffer_event_data(event): get the data from the event
This is the function to use to get the actual data
from the event. Note, it is only a pointer to the
data inside the buffer. This data must be copied to
another location otherwise you risk it being written
over in the buffer.
ring_buffer_lock: A way to lock the entire buffer.
ring_buffer_unlock: unlock the buffer.
ring_buffer_alloc: create a new ring buffer. Can choose between
overwrite or consumer/producer mode. Overwrite will
overwrite old data, where as consumer producer will
throw away new data if the consumer catches up with the
producer. The consumer/producer is the default.
ring_buffer_free: free the ring buffer.
ring_buffer_resize: resize the buffer. Changes the size of each cpu
buffer. Note, it is up to the caller to provide that
the buffer is not being used while this is happening.
This requirement may go away but do not count on it.
ring_buffer_lock_reserve: locks the ring buffer and allocates an
entry on the buffer to write to.
ring_buffer_unlock_commit: unlocks the ring buffer and commits it to
the buffer.
ring_buffer_write: writes some data into the ring buffer.
ring_buffer_peek: Look at a next item in the cpu buffer.
ring_buffer_consume: get the next item in the cpu buffer and
consume it. That is, this function increments the head
pointer.
ring_buffer_read_start: Start an iterator of a cpu buffer.
For now, this disables the cpu buffer, until you issue
a finish. This is just because we do not want the iterator
to be overwritten. This restriction may change in the future.
But note, this is used for static reading of a buffer which
is usually done "after" a trace. Live readings would want
to use the ring_buffer_consume above, which will not
disable the ring buffer.
ring_buffer_read_finish: Finishes the read iterator and reenables
the ring buffer.
ring_buffer_iter_peek: Look at the next item in the cpu iterator.
ring_buffer_read: Read the iterator and increment it.
ring_buffer_iter_reset: Reset the iterator to point to the beginning
of the cpu buffer.
ring_buffer_iter_empty: Returns true if the iterator is at the end
of the cpu buffer.
ring_buffer_size: returns the size in bytes of each cpu buffer.
Note, the real size is this times the number of CPUs.
ring_buffer_reset_cpu: Sets the cpu buffer to empty
ring_buffer_reset: sets all cpu buffers to empty
ring_buffer_swap_cpu: swaps a cpu buffer from one buffer with a
cpu buffer of another buffer. This is handy when you
want to take a snap shot of a running trace on just one
cpu. Having a backup buffer, to swap with facilitates this.
Ftrace max latencies use this.
ring_buffer_empty: Returns true if the ring buffer is empty.
ring_buffer_empty_cpu: Returns true if the cpu buffer is empty.
ring_buffer_record_disable: disable all cpu buffers (read only)
ring_buffer_record_disable_cpu: disable a single cpu buffer (read only)
ring_buffer_record_enable: enable all cpu buffers.
ring_buffer_record_enabl_cpu: enable a single cpu buffer.
ring_buffer_entries: The number of entries in a ring buffer.
ring_buffer_overruns: The number of entries removed due to writing wrap.
ring_buffer_time_stamp: Get the time stamp used by the ring buffer
ring_buffer_normalize_time_stamp: normalize the ring buffer time stamp
into nanosecs.
I still need to implement the GTOD feature. But we need support from
the cpu frequency infrastructure. But this can be done at a later
time without affecting the ring buffer interface.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Steven Rostedt [Tue, 30 Sep 2008 03:02:37 +0000 (23:02 -0400)]
ftrace: give time for wakeup test to run
It is possible that the testing thread in the ftrace wakeup test does not
run before we stop the trace. This will cause the trace to fail since nothing
will be in the buffers.
This patch adds a small wait in the wakeup test to allow for the woken task
to run and be traced.
Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
ftrace/fastboot: disable tracers self-tests when boot tracer is selected
The tracing engine resets the ring buffer and the tracers touch it
too during self-tests. These self-tests happen during tracers registering
and work against boot tracing which is logging initcalls.
We have to disable tracing self-tests if the boot-tracer is selected.
tracing/ftrace: launch boot tracing after pre-smp initcalls
Launch the boot tracing inside the initcall_debug area. Old printk
have not been removed to keep the old way of initcall tracing for
backward compatibility.
It's primary purpose is to be able to trace the initcalls.
It is intended to be used with scripts/bootgraph.pl after some small
improvements.
Note that it is not active after its init. To avoid tracing (and so
crashing) before the whole tracing engine init, you have to explicitly
call start_boot_trace() after do_pre_smp_initcalls() to enable it.
Arjan van de Ven [Sat, 13 Sep 2008 16:36:06 +0000 (09:36 -0700)]
tracing/fastboot: add a script to visualize the kernel boot process / time
When optimizing the kernel boot time, it's very valuable to visualize
what is going on at which time. In addition, with the fastboot asynchronous
initcall level, it's very valuable to see which initcall gets run where
and when.
This patch adds a script to turn a dmesg into a SVG graph (that can be
shown with tools such as InkScape, Gimp or Firefox) and a small change
to the initcall code to print the PID of the thread calling the initcall
(so that the script can work out the parallelism).
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Lai Jiangshan [Fri, 10 Oct 2008 06:43:57 +0000 (14:43 +0800)]
markers: bit-field is not thread-safe nor smp-safe
bit-field is not thread-safe nor smp-safe.
struct marker_entry.rcu_pending is not protected by any lock
in rcu-callback free_old_closure().
so we must turn it into a safe type.
detail:
I suppose rcu_pending and ptype are store in struct marker_entry.tmp1
free_old_closure() side: change ptype side:
| load struct marker_entry.tmp1
--------------------------------|--------------------------------
| change ptype bit in tmp1
load struct marker_entry.tmp1 |
change rcu_pending bit in tmp1 |
store tmp1 |
--------------------------------|--------------------------------
| store tmp1
now this result equals that free_old_closure() do not change rcu_pending
bit, bug! This bug will cause redundant rcu_barrier_sched() called.
not too harmful.
----- corresponding:
free_old_closure() side: change ptype side:
load struct marker_entry.tmp1 |
--------------------------------|--------------------------------
| load struct marker_entry.tmp1
change rcu_pending bit in tmp1 |
| change ptype bit in tmp1
| store tmp1
--------------------------------|--------------------------------
store tmp1 |
now this result equals that change ptype side do not change ptype
bit, bug! this bug cause marker_probe_cb() access to invalid memory.
oops!
Lai Jiangshan discovered a reentrancy issue with markers and fixed it by
adding synchronize_sched() calls at each registration/unregistraiton.
It works, but it removes the ability to do batch
registration/unregistration and can cause registration of ~100 markers
to take about 30 seconds on a loaded machine (synchronize_sched() is
much slower on such workloads).
This patch implements a version of the fix which won't slow down marker batch
registration/unregistration. It also go back to the original non-synchronized
reg/unreg.
We need a marker_synchronize_unregister() before the end of exit() to make sure
every probe callers have exited the non preemptible section and thus are not
executing the probe code anymore.
Document the need for a marker_synchronize_unregister() before the end of
exit() to make sure every probe callers have exited the non preemptible
section and thus are not executing the probe code anymore.
Need a marker_synchronize_unregister() before the end of exit() to make sure
every probe callers have exited the non preemptible section and thus are not
executing the probe code anymore.
markers: fix unregister bug and reenter bug, cleanup
Use the new rcu_read_lock_sched/unlock_sched() in marker code around the call
site instead of preempt_disable/enable(). It helps reviewing the code more
easily.
Create marker_synchronize_unregister() which must be called before the end of
exit() to make sure every probe callers have exited the non preemptible section
and thus are not executing the probe code anymore.
Lai Jiangshan [Mon, 29 Sep 2008 08:00:05 +0000 (16:00 +0800)]
markers: fix unregister bug and reenter bug
unregister bug:
codes using makers are typically calling marker_probe_unregister()
and then destroying the data that marker_probe_func needs(or
unloading this module). This is bug when the corresponding
marker_probe_func is still running(on other cpus),
it is using the destroying/ed data.
we should call synchronize_sched() after marker_update_probes().
reenter bug:
marker_probe_register(), marker_probe_unregister() and
marker_probe_unregister_private_data() are not reentrant safe
functions. these 3 functions release markers_mutex and then
require it again and do "entry->oldptr = old; ...", but entry->oldptr
maybe is using now for these 3 functions may reenter when markers_mutex
is released.
we use synchronize_sched() instead of call_rcu_sched() to fix
this bug. actually we can do:
"
if (entry->rcu_pending)
rcu_barrier_sched();
"
after require markers_mutex again. but synchronize_sched()
is better and simpler. For these 3 functions are not critical path.
It is because ftrace_modify_code() calls copy_to_user and
copy_from_user.
These functions have been inserted after guessing that there
couldn't be any race condition but copy_[to/from]_user might
sleep and __ftrace_update_code is called with local_irq_saved.
Harvey Harrison [Tue, 23 Sep 2008 22:05:46 +0000 (15:05 -0700)]
x86: suppress trivial sparse signedness warnings
Could just as easily change the three casts to cast to the correct
type...this patch changes the type of ftrace_nop instead.
Supresses sparse warnings:
arch/x86/kernel/ftrace.c:157:14: warning: incorrect type in assignment (different signedness)
arch/x86/kernel/ftrace.c:157:14: expected long *static [toplevel] ftrace_nop
arch/x86/kernel/ftrace.c:157:14: got unsigned long *<noident>
arch/x86/kernel/ftrace.c:161:14: warning: incorrect type in assignment (different signedness)
arch/x86/kernel/ftrace.c:161:14: expected long *static [toplevel] ftrace_nop
arch/x86/kernel/ftrace.c:161:14: got unsigned long *<noident>
arch/x86/kernel/ftrace.c:165:14: warning: incorrect type in assignment (different signedness)
arch/x86/kernel/ftrace.c:165:14: expected long *static [toplevel] ftrace_nop
arch/x86/kernel/ftrace.c:165:14: got unsigned long *<noident>
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
projects / linux-2.6-omap-h63xx.git / log