The current definition of wksidarr works fine on little endian arches
(since cpu_to_le32 is a no-op there), but on big-endian arches, it fails
to compile with this error:
error: braced-group within expression allowed only inside a function
The problem is that this static declaration has cpu_to_le32 embedded
within it, and that expands into a function macro. We need to use
__constant_cpu_to_le32() instead.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: Steven French <sfrench@us.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Try this:
mount a share with unix extensions
create a file on it
umount the share
You'll get the following message in the ring buffer:
VFS: Busy inodes after unmount of cifs. Self-destruct in 5 seconds. Have a
nice day...
...the problem is that cifs_get_inode_info_unix is creating and hashing
a new inode even when it's going to return error anyway. The first
lookup when creating a file returns an error so we end up leaking this
inode before we do the actual create. This appears to be a regression
caused by commit 0e4bbde94f.
The following patch seems to fix it for me, and fixes a minor
formatting nit as well.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix FRV irqs_disabled() to return an int, not an unsigned long to avoid
this warning:
kernel/sched.c: In function '__might_sleep':
kernel/sched.c:8198: warning: format '%d' expects type 'int', but argument 3 has type 'long unsigned int'
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Philippe Elie <phil.el@wanadoo.fr>
Cc: John Levon <levon@movementarian.org>
Cc: Maynard Johnson <maynardj@us.ibm.com>
Cc: Richard Purdie <rpurdie@openedhand.com>
Cc: Daniel Hansel <daniel.hansel@linux.vnet.ibm.com>
Cc: Jason Yeh <jason.yeh@amd.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Robert Richter <robert.richter@amd.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cortland Setlow pointed out a bug in ov7670.c where the result from
ov7670_read() was just being checked for !0, rather than <0. This made me
realize that ov7670_read's semantics were rather confusing; it both fills
in 'value' with the result, and returns it. This is goes against general
kernel convention; so rather than fixing callers, let's fix the function.
This makes ov7670_read return <0 in the case of an error, and 0 upon
success. Thus, code like:
res = ov7670_read(...);
if (!res)
goto error;
..will work properly.
Signed-off-by: Cortland Setlow <csetlow@tower-research.com>
Signed-off-by: Andres Salomon <dilinger@debian.org>
Acked-by: Jonathan Corbet <corbet@lwn.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I had 8250.nr_uarts=16 in the boot line of a test kernel and I had a weird
mysterious crash in sysfs. After taking an in-depth look I realized that
CONFIG_SERIAL_8250_NR_UARTS was set to 4 and I was walking off the end of
the serial8250_ports array.
Ouch!!!
Don't let this happen to someone else.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Alan Cox <alan@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch is a bugfix for how defio handles multiple processes manipulating
the same framebuffer.
Thanks to Bernard Blackham for identifying this bug.
It occurs when two applications mmap the same framebuffer and concurrently
write to the same page. Normally, this doesn't occur since only a single
process mmaps the framebuffer. The symptom of the bug is that the mapping
applications will hang. The cause is that defio incorrectly tries to add the
same page twice to the pagelist. The solution I have is to walk the pagelist
and check for a duplicate before adding. Since I needed to walk the pagelist,
I now also keep the pagelist in sorted order.
Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: Bernard Blackham <bernard@largestprime.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Coverity CID: 1356 RESOURCE_LEAK
I found a very old patch for this that was Acked but did not get applied
https://lists.linux-foundation.org/pipermail/kernel-janitors/2006-September/016362.html
There looks to be a small leak in isdn_writebuf_stub() in isdn_common.c, when
copy_from_user() returns an un-copied data length (length != 0). The below
patch should be a minimally invasive fix.
Signed-off-by: Darren Jenkins <darrenrjenkins@gmailcom>
Acked-by: Karsten Keil <kkeil@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Coverity CID: 2172 RESOURCE_LEAK
When pool_allocate() tries to enlarge a packet, if it can not allocate enough
memory, it returns NULL without first freeing the old packet.
This patch just frees the packet first.
Signed-off-by: Darren Jenkins <darrenrjenkins@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If you do a modremove of any sas driver, you run into an oops on
shutdown when the host is removed (coming from the host bsg device).
The root cause seems to be that there's a use after free of the
bsg_class_device: In bsg_kref_release_function, this is used (to do a
put_device(bcg->parent) after bcg->release has been called. In sas (and
possibly many other things) bcd->release frees the queue which contains
the bsg_class_device, so we get a put_device on unreferenced memory.
Fix this by taking a copy of the pointer to the parent before releasing
bsg.
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
There's a fault on the FC controllers that makes them not respond
correctly to MSI. The SPI controllers are fine, but are likely to be
onboard on older motherboards which don't handle MSI correctly, so
default both these cases to disabled. Enable by setting the module
parameter mpt_msi_enable=1.
For the SAS case, enable MSI by default, but it can be disabled by
setting the module parameter mpt_msi_enable=0.
Cc: "Prakash, Sathya" <sathya.prakash@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Bevore issuing any s390 crypto operation check whether the
CPACF facility is enabled in the facility list. That way a
virtualization layer can prevent usage of the CPACF facility
regardless of the availability of the crypto instructions.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fix size of LDT entries. On x86-64, ldt_desc is a double-sized descriptor.
Signed-off-by: Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
On three of the several paths in entry_64.S that call
do_notify_resume() on the way back to user mode, we fail to properly
check again for newly-arrived work that requires another call to
do_notify_resume() before going to user mode. These paths set the
mask to check only _TIF_NEED_RESCHED, but this is wrong. The other
paths that lead to do_notify_resume() do this correctly already, and
entry_32.S does it correctly in all cases.
All paths back to user mode have to check all the _TIF_WORK_MASK
flags at the last possible stage, with interrupts disabled.
Otherwise, we miss any flags (TIF_SIGPENDING for example) that were
set any time after we entered do_notify_resume(). More work flags
can be set (or left set) synchronously inside do_notify_resume(), as
TIF_SIGPENDING can be, or asynchronously by interrupts or other CPUs
(which then send an asynchronous interrupt).
There are many different scenarios that could hit this bug, most of
them races. The simplest one to demonstrate does not require any
race: when one signal has done handler setup at the check before
returning from a syscall, and there is another signal pending that
should be handled. The second signal's handler should interrupt the
first signal handler before it actually starts (so the interrupted PC
is still at the handler's entry point). Instead, it runs away until
the next kernel entry (next syscall, tick, etc).
This test behaves correctly on 32-bit kernels, and fails on 64-bit
(either 32-bit or 64-bit test binary). With this fix, it works.
#define _GNU_SOURCE
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <sys/ucontext.h>
#ifndef REG_RIP
#define REG_RIP REG_EIP
#endif
static sig_atomic_t hit1, hit2;
static void
handler (int sig, siginfo_t *info, void *ctx)
{
ucontext_t *uc = ctx;
if ((void *) uc->uc_mcontext.gregs[REG_RIP] == &handler)
{
if (sig == SIGUSR1)
hit1 = 1;
else
hit2 = 1;
}
printf ("%s at %#lx\n", strsignal (sig),
uc->uc_mcontext.gregs[REG_RIP]);
}
int
main (void)
{
struct sigaction sa;
sigset_t set;
sigemptyset (&sa.sa_mask);
sa.sa_flags = SA_SIGINFO;
sa.sa_sigaction = &handler;
if (sigaction (SIGUSR1, &sa, NULL)
|| sigaction (SIGUSR2, &sa, NULL))
return 2;
sigemptyset (&set);
sigaddset (&set, SIGUSR1);
sigaddset (&set, SIGUSR2);
if (sigprocmask (SIG_BLOCK, &set, NULL))
return 3;
printf ("main at %p, handler at %p\n", &main, &handler);
raise (SIGUSR1);
raise (SIGUSR2);
if (sigprocmask (SIG_UNBLOCK, &set, NULL))
return 4;
if (hit1 + hit2 == 1)
{
puts ("PASS");
return 0;
}
puts ("FAIL");
return 1;
}
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We have two conflicting DMA-based quirks in there for the same set of
boxes (HP nx6325 and nx6125) and one of them actually breaks my box.
So remove the extra code.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: =?iso-8859-1?q?T=F6r=F6k_Edwin?= <edwintorok@gmail.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove explicit lock_kernel() calls and document why the code is safe.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This patch corrects the handling of write operations to the IPMI watchdog
to work as intended by returning the number of characters actually
processed. Without this patch, an "echo V >/dev/watchdog" enables the
watchdog if IPMI is providing the watchdog function.
Signed-off-by: Mark Rustad <MRustad@gmail.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
In the course of the recent unification of the NMI watchdog an assignment
to timer_ack to switch off unnecesary POLL commands to the 8259A in the
case of a watchdog failure has been accidentally removed. The statement
used to be limited to the 32-bit variation as since the rewrite of the
timer code it has been relevant for the 82489DX only. This change brings
it back.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is no such entity as ISA IRQ2. The ACPI spec does not make it
explicitly clear, but does not preclude it either -- all it says is ISA
legacy interrupts are identity mapped by default (subject to overrides),
but it does not state whether IRQ2 exists or not. As a result if there is
no IRQ0 override, then IRQ2 is normally initialised as an ISA interrupt,
which implies an edge-triggered line, which is unmasked by default as this
is what we do for edge-triggered I/O APIC interrupts so as not to miss an
edge.
To the best of my knowledge it is useless, as IRQ2 has not been in use
since the PC/AT as back then it was taken by the 8259A cascade interrupt
to the slave, with the line position in the slot rerouted to newly-created
IRQ9. No device could thus make use of this line with the pair of 8259A
chips. Now in theory INTIN2 of the I/O APIC may be usable, but the
interrupt of the device wired to it would not be available in the PIC mode
at all, so I seriously doubt if anybody decided to reuse it for a regular
device.
However there are two common uses of INTIN2. One is for IRQ0, with an
ACPI interrupt override (or its equivalent in the MP table). But in this
case IRQ2 is gone entirely with INTIN0 left vacant. The other one is for
an 8959A ExtINTA cascade. In this case IRQ0 goes to INTIN0 and if ACPI is
used INTIN2 is assumed to be IRQ2 (there is no override and ACPI has no
way to report ExtINTA interrupts). This is where a problem happens.
The problem is INTIN2 is configured as a native APIC interrupt, with a
vector assigned and the mask cleared. And the line may indeed get active
and inject interrupts if the master 8959A has its timer interrupt enabled
(it might happen for other interrupts too, but they are normally masked in
the process of rerouting them to the I/O APIC). There are two cases where
it will happen:
* When the I/O APIC NMI watchdog is enabled. This is actually a misnomer
as the watchdog pulses are delivered through the 8259A to the LINT0
inputs of all the local APICs in the system. The implication is the
output of the master 8259A goes high and low repeatedly, signalling
interrupts to INTIN2 which is enabled too!
[The origin of the name is I think for a brief period during the
development we had a capability in our code to configure the watchdog to
use an I/O APIC input; that would be INTIN2 in this scenario.]
* When the native route of IRQ0 via INTIN0 fails for whatever reason -- as
it happens with the system considered here. In this scenario the timer
pulse is delivered through the 8259A to LINT0 input of the local APIC of
the bootstrap processor, quite similarly to how is done for the watchdog
described above. The result is, again, INTIN2 receives these pulses
too. Rafael's system used to escape this scenario, because an incorrect
IRQ0 override would occupy INTIN2 and prevent it from being unmasked.
My conclusion is IRQ2 should be excluded from configuration in all the
cases and the current exception for ACPI systems should be lifted. The
reason being the exception not only being useless, but harmful as well.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Unlike the 32-bit one, the 64-bit variation of the LVT0 setup code for
the "8259A Virtual Wire" through the local APIC timer configuration does
not fully configure the relevant irq_chip structure. Instead it relies on
the preceding I/O APIC code to have set it up, which does not happen if
the I/O APIC variants have not been tried.
The patch includes corresponding changes to the 32-bit variation too
which make them both the same, barring a small syntactic difference
involving sequence of functions in the source. That should work as an aid
with the upcoming merge.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
IRQ0 is edge-triggered, but the "8259A Virtual Wire" through the local
APIC configuration in the 32-bit version uses the "fasteoi" handler
suitable for level-triggered APIC interrupt. Rewrite code so that the
"edge" handler is used. The 64-bit version uses different code and is
unaffected.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In dwarf2_32.h, test for CONFIG_AS_CFI instead of
CONFIG_UNWIND_INFO. Turns out that searching for UNWIND_INFO
returns no match in any Kconfig or Makefile, so we're really
just throwing everything away regarding dwarf frames for i386.
The test that generates CONFIG_AS_CFI does not have anything
x86_64-specific, and right now, checking V=1 builds shows me
that the flags is there anyway, although unused.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In dwarf_64.h header, use the "ignore" macro the way
i386 does.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The RING0_INT_FRAME macro defines a CFI_STARTPROC.
So we should really be using CFI_ENDPROC after it.
Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently, ipr does not support HDIO_GET_IDENTITY to SATA devices.
An oops occurs if userspace attempts to send the command. Since hald
issues the command, ensure we fail the ioctl in ipr. This is a
temporary solution to the oops. Once the ipr libata EH conversion
is upstream, ipr will fully support HDIO_GET_IDENTITY.
Tested-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
libata-acpi: don't call sleeping function from invalid context
Added Targa Visionary 1000 IDE adapter to pata_sis.c
libata-acpi: filter out DIPM enable
When we release the iclog, we do an atomic_dec_and_lock to determine if
we are the last reference and need to trigger update of log headers and
writeout. However, in xlog_state_get_iclog_space() we also need to
check if we have the last reference count there. If we do, we release
the log buffer, otherwise we decrement the reference count.
But the compare and decrement in xlog_state_get_iclog_space() is not
atomic, so both places can see a reference count of 2 and neither will
release the iclog. That leads to a filesystem hang.
Close the race by replacing the atomic_read() and atomic_dec() pair with
atomic_add_unless() to ensure that they are executed atomically.
Signed-off-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Tim Shimmin <tes@sgi.com>
Tested-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
i spent a fair amount of time chasing a 64-bit bootup crash that manifested
itself as bootup segfaults:
S10network[1825]: segfault at 7f3e2b5d16b8 ip 00000031108748c9 sp 00007fffb9c14c70 error 4 in libc-2.7.so[3110800000+14d000]
eventually causing init to die and panic the system:
Kernel panic - not syncing: Attempted to kill init!
Pid: 1, comm: init Not tainted 2.6.26-rc9-tip #13878
after a maratonic bisection session, the bad commit turned out to be:
| b7675791859075418199c7af86a116ea34eaf5bd is first bad commit
| commit b7675791859075418199c7af86a116ea34eaf5bd
| Author: Jeremy Fitzhardinge <jeremy@goop.org>
| Date: Wed Jun 25 00:19:00 2008 -0400
|
| x86: remove open-coded save/load segment operations
|
| This removes a pile of buggy open-coded implementations of savesegment
| and loadsegment.
after some more bisection of this patch itself, it turns out that what
makes the difference are the savesegment() changes to __switch_to().
Taking a look at this portion of arch/x86/kernel/process_64.o revealed
this crutial difference:
| good: 99c: 8c e0 mov %fs,%eax
| 99e: 89 45 cc mov %eax,-0x34(%rbp)
|
| bad: 99c: 8c 65 cc mov %fs,-0x34(%rbp)
which is due to:
| unsigned fsindex;
| - asm volatile("movl %%fs,%0" : "=r" (fsindex));
| + savesegment(fs, fsindex);
savesegment() is implemented as:
#define savesegment(seg, value) \
asm("mov %%" #seg ",%0":"=rm" (value) : : "memory")
note the "m" modifier - it allows GCC to generate the segment move
into a memory operand as well.
But regarding segment operands there's a subtle detail in the x86
instruction set: the above 16-bit moves are zero-extend, but only
if it goes to a register.
If it goes to a memory operand, -0x34(%rbp) in the above case, there's
no zero-extend to 32-bit and the instruction will only save 16 bits
instead of the intended 32-bit.
The other 16 bits is random data - which can cause problems when that
value is used later on.
The solution is to only allow segment operands to go to registers.
This fix allows my test-system to boot up without crashing.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
fix:
kernel/trace/ftrace.c:1615: error: 'ftraced_suspend' undeclared (first use in this function)
kernel/trace/ftrace.c:1615: error: (Each undeclared identifier is reported only once
kernel/trace/ftrace.c:1615: error: for each function it appears in.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The sched_clock code currently tries to keep all CPU clocks of all CPUS
somewhat in sync. At every clock tick it records the gtod clock and
uses that and jiffies and the TSC to calculate a CPU clock that tries to
stay in sync with all the other CPUs.
ftrace depends heavily on this timer and it detects when this timer
"jumps". One problem is that the TSC and the gtod also drift.
When the TSC is 0.1% faster or slower than the gtod it is very noticeable
in ftrace. To help compensate for this, I've added a multiplier that
tries to keep the CPU clock updating at the same rate as the gtod.
I've tried various ways to get it to be in sync and this ended up being
the most reliable. At every scheduler tick we calculate the new multiplier:
multi = delta_gtod / delta_TSC
This means we perform a 64 bit divide at the tick (once a HZ). A shift
is used to handle the accuracy.
Other methods that failed due to dynamic HZ are:
(not used) multi += (gtod - tsc) / delta_gtod
(not used) multi += (gtod - (last_tsc + delta_tsc)) / delta_gtod
as well as other variants.
This code still allows for a slight drift between TSC and gtod, but
it keeps the damage down to a minimum.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
To read the gtod we need to grab the xtime lock for read. Reading the gtod
before the TSC can cause a bigger gab if the xtime lock is contended.
This patch simply reverses the order to read the TSC after the gtod.
The locking in the reading of the gtod handles any barriers one might
think is needed.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reading the CPU clock should try to stay accurate within the CPU.
By reading the CPU clock from another CPU and updating the deltas can
cause unneeded jumps when reading from the local CPU.
This patch changes the code to update the last read TSC only when read
from the local CPU.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The algorithm to calculate the 'now' of another CPU is not correct.
At each scheduler tick, each CPU records the last sched_clock and
gtod (tick_raw and tick_gtod respectively). If the TSC is somewhat the
same in speed between two clocks the algorithm would be:
tick_gtod1 + (now1 - tick_raw1) = tick_gtod2 + (now2 - tick_raw2)
To calculate now2 we would have:
now2 = (tick_gtod1 - tick_gtod2) + (tick_raw2 - tick_raw1) + now1
Currently the algorithm is:
now2 = (tick_gtod1 - tick_gtod2) + (tick_raw1 - tick_raw2) + now1
This solves most of the rest of the issues I've had with timestamps in
ftace.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Working with ftrace I would get large jumps of 11 millisecs or more with
the clock tracer. This killed the latencing timings of ftrace and also
caused the irqoff self tests to fail.
What was happening is with NO_HZ the idle would stop the jiffy counter and
before the jiffy counter was updated the sched_clock would have a bad
delta jiffies to compare with the gtod with the maximum.
The jiffies would stop and the last sched_tick would record the last gtod.
On wakeup, the sched clock update would compare the gtod + delta jiffies
(which would be zero) and compare it to the TSC. The TSC would have
correctly (with a stable TSC) moved forward several jiffies. But because the
jiffies has not been updated yet the clock would be prevented from moving
forward because it would appear that the TSC jumped too far ahead.
The clock would then virtually stop, until the jiffies are updated. Then
the next sched clock update would see that the clock was very much behind
since the delta jiffies is now correct. This would then jump the clock
forward by several jiffies.
This caused ftrace to report several milliseconds of interrupts off
latency at every resume from NO_HZ idle.
This patch adds hooks into the nohz code to disable the checking of the
maximum clock update when nohz is in effect. It resumes the max check
when nohz has updated the jiffies again.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
With keeping the max and min sched time within one jiffy of the gtod clock
was too tight. Just before a schedule tick the max could easily be hit, as
well as just after a schedule_tick the min could be hit. This caused the
clock to jump around by a jiffy.
This patch widens the minimum to
last gtod + (delta_jiffies ? delta_jiffies - 1 : 0) * TICK_NSECS
and the maximum to
last gtod + (2 + delta_jiffies) * TICK_NSECS
This keeps the minum to gtod or if one jiffy less than delta jiffies
and the maxim 2 jiffies ahead of gtod. This may cause unstable TSCs to be
a bit more sporadic, but it helps keep a clock with a stable TSC working well.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The sched_clock code tries to keep within the gtod time by one tick (jiffy).
The current code mistakenly keeps track of the delta jiffies between
updates of the clock, where the the delta is used to compare with the
number of jiffies that have past since an update of the gtod. The gtod is
updated at each schedule tick not each sched_clock update. After one
jiffy passes the clock is updated fine. But the delta is taken from the
last update so if the next update happens before the next tick the delta
jiffies used will be incorrect.
This patch changes the code to check the delta of jiffies between ticks
and not updates to match the comparison of the updates with the gtod.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently the function tracer uses the global tracer_enabled variable that
is used to keep track if the tracer is enabled or not. The function tracing
startup needs to be separated out, otherwise the internal happenings of
the tracer startup is also recorded.
This patch creates a ftrace_function_enabled variable to all the starting
of the function traces to happen after everything has been started.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
It has been suggested that I add a way to disable the function tracer
on an oops. This code adds a ftrace_kill_atomic. It is not meant to be
used in normal situations. It will disable the ftrace tracer, but will
not perform the nice shutdown that requires scheduling.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This is more of a clean up. Currently the function tracer initializes the
tracer with which ever CPU was last used for tracing. This value isn't
realy useful for function tracing, but at least it should be something other
than a random number.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Enabling the wakeup tracer before enabling the function tracing causes
some strange results due to the dynamic enabling of the functions.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There is no CONFIG_PREEMPT_DESKTOP. Use the proper entry CONFIG_PREEMPT.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
After the sched_clock code has been removed from sched.c we can now trace
the scheduler. The scheduler has a lot of functions that would be worth
tracing.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When CONFIG_FTRACE is not enabled, the tracing_start_functon_trace
and tracing_stop_function_trace should be nops.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We have two markers now that are enabled on sched_switch. One that records
the context switching and the other that records task wake ups. Currently
we enable the tracing first and then set the markers. This causes some
confusing traces:
# tracer: sched_switch
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
trace-cmd-3973 [00] 115.834817: 3973:120:R + 3: 0:S
trace-cmd-3973 [01] 115.834910: 3973:120:R + 6: 0:S
trace-cmd-3973 [02] 115.834910: 3973:120:R + 9: 0:S
trace-cmd-3973 [03] 115.834910: 3973:120:R + 12: 0:S
trace-cmd-3973 [02] 115.834910: 3973:120:R + 9: 0:S
<idle>-0 [02] 115.834910: 0:140:R ==> 3973:120:R
Here we see that trace-cmd with PID 3973 wakes up task 9 but the next line
shows the idle task doing a context switch to task 3973.
Enabling the tracing to _after_ the markers are set creates a much saner
output:
# tracer: sched_switch
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
<idle>-0 [02] 7922.634225: 0:140:R ==> 4790:120:R
trace-cmd-4789 [03] 7922.634225: 0:140:R + 4790:120:R
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
