gfs2_lock() will skip locks on file which have mode set to 02666. This is a problem in cases where the mode of the file is changed after a process has obtained a lock on the file. Such a lock will be skipped and will result in a BUG in locks_remove_flock().
gfs2_lock() should skip the check for mandatory locks when unlocking a file.
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Since pick_next_highest_task_rt() already iterates all the cgroups and
is really only interested in tasks, skip over the !task entries.
Reported-by: Dhaval Giani <dhaval.giani@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Dhaval Giani <dhaval.giani@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Export perf_trace_regs and perf_arch_fetch_caller_regs since module will
use these.
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
[ use EXPORT_PER_CPU_SYMBOL_GPL() ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4B989C1B.2090407@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
What happens is that we schedule badly like:
<...>-1987 [019] 280.252808: x86_pmu_start: event-46/1300c0: idx: 0
<...>-1987 [019] 280.252811: x86_pmu_start: event-47/1300c0: idx: 1
<...>-1987 [019] 280.252812: x86_pmu_start: event-48/1300c0: idx: 2
<...>-1987 [019] 280.252813: x86_pmu_start: event-49/1300c0: idx: 3
<...>-1987 [019] 280.252814: x86_pmu_start: event-50/1300c0: idx: 32
<...>-1987 [019] 280.252825: x86_pmu_stop: event-46/1300c0: idx: 0
<...>-1987 [019] 280.252826: x86_pmu_stop: event-47/1300c0: idx: 1
<...>-1987 [019] 280.252827: x86_pmu_stop: event-48/1300c0: idx: 2
<...>-1987 [019] 280.252828: x86_pmu_stop: event-49/1300c0: idx: 3
<...>-1987 [019] 280.252829: x86_pmu_stop: event-50/1300c0: idx: 32
<...>-1987 [019] 280.252834: x86_pmu_start: event-47/1300c0: idx: 1
<...>-1987 [019] 280.252834: x86_pmu_start: event-48/1300c0: idx: 2
<...>-1987 [019] 280.252835: x86_pmu_start: event-49/1300c0: idx: 3
<...>-1987 [019] 280.252836: x86_pmu_start: event-50/1300c0: idx: 32
<...>-1987 [019] 280.252837: x86_pmu_start: event-51/1300c0: idx: 32 *FAIL*
This happens because we only iterate the n_running events in the first
pass, and reset their index to -1 if they don't match to force a
re-assignment.
Now, in our RR example, n_running == 0 because we fully unscheduled, so
event-50 will retain its idx==32, even though in scheduling it will have
gotten idx=0, and we don't trigger the re-assign path.
The easiest way to fix this is the below patch, which simply validates
the full assignment in the second pass.
Reported-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268311069.5037.31.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix:
arch/powerpc/kernel/perf_event.c:1334: error: 'power_pmu_notifier' undeclared (first use in this function)
arch/powerpc/kernel/perf_event.c:1334: error: (Each undeclared identifier is reported only once
arch/powerpc/kernel/perf_event.c:1334: error: for each function it appears in.)
arch/powerpc/kernel/perf_event.c:1334: error: implicit declaration of function 'power_pmu_notifier'
arch/powerpc/kernel/perf_event.c:1334: error: implicit declaration of function 'register_cpu_notifier'
Due to commit 3f6da390 (perf: Rework and fix the arch CPU-hotplug hooks).
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reduce warning message output to one line only instead of per
cpu.
Signed-of-by: Mike Travis <travis@sgi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: x86@kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Without this change, the install path is relative to
prefix/DESTDIR where prefix is automatically set to $HOME.
This can produce unexpected results. For example:
make -C tools/perf DESTDIR=/home/jkacur/tmp install-man
creates the directory: /home/jkacur/home/jkacur/tmp/share/...
instead of the expected: /home/jkacur/tmp/share/...
Signed-off-by: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Kyle McMartin <kyle@redhat.com>
Cc: <stable@kernel.org>
LKML-Reference: <1268312220-12880-1-git-send-email-jkacur@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
From : Ananth N Mavinakayanahalli <ananth@in.ibm.com>
When freeing the instruction slot, the arithmetic to calculate
the index of the slot in the page needs to account for the total
size of the instruction on the various architectures.
Calculate the index correctly when freeing the out-of-line
execution slot.
Reported-by: Sachin Sant <sachinp@in.ibm.com>
Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <4B9667AB.9050507@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We haven't used the "orig_rq" variable since
055a00865d "Fix/add missing update_rq_clock() calls"
Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: efault@gmx.de
LKML-Reference: <20100306111752.GL4958@bicker>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Replace the calls to read_barrier_depends() in
ftrace_list_func() with rcu_dereference_raw() to improve
readability. The reason that we use rcu_dereference_raw() here
is that removed entries are never freed, instead they are simply
leaked. This is one of a very few cases where use of
rcu_dereference_raw() is the long-term right answer. And I
don't yet know of any others. ;-)
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1267830207-9474-1-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
At present, the perf subcommands that do system-wide monitoring
(perf stat, perf record and perf top) don't work properly unless
the online cpus are numbered 0, 1, ..., N-1. These tools ask
for the number of online cpus with sysconf(_SC_NPROCESSORS_ONLN)
and then try to create events for cpus 0, 1, ..., N-1.
This creates problems for systems where the online cpus are
numbered sparsely. For example, a POWER6 system in
single-threaded mode (i.e. only running 1 hardware thread per
core) will have only even-numbered cpus online.
This fixes the problem by reading the /sys/devices/system/cpu/online
file to find out which cpus are online. The code that does that is in
tools/perf/util/cpumap.[ch], and consists of a read_cpu_map()
function that sets up a cpumap[] array and returns the number of
online cpus. If /sys/devices/system/cpu/online can't be read or
can't be parsed successfully, it falls back to using sysconf to
ask how many cpus are online and sets up an identity map in cpumap[].
The perf record, perf stat and perf top code then calls
read_cpu_map() in the system-wide monitoring case (instead of
sysconf) and uses cpumap[] to get the cpu numbers to pass to
perf_event_open.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
LKML-Reference: <20100310093609.GA3959@brick.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Anton Blanchard found that he could reliably make the kernel hit a
BUG_ON in the slab allocator by taking a cpu offline and then online
while a system-wide perf record session was running.
The reason is that when the cpu comes up, we completely reinitialize
the ctx field of the struct perf_cpu_context for the cpu. If there is
a system-wide perf record session running, then there will be a struct
perf_event that has a reference to the context, so its refcount will
be 2. (The perf_event has been removed from the context's group_entry
and event_entry lists by perf_event_exit_cpu(), but that doesn't
remove the perf_event's reference to the context and doesn't decrement
the context's refcount.)
When the cpu comes up, perf_event_init_cpu() gets called, and it calls
__perf_event_init_context() on the cpu's context. That resets the
refcount to 1. Then when the perf record session finishes and the
perf_event is closed, the refcount gets decremented to 0 and the
context gets kfreed after an RCU grace period. Since the context
wasn't kmalloced -- it's part of a per-cpu variable -- bad things
happen.
In fact we don't need to completely reinitialize the context when the
cpu comes up. It's sufficient to initialize the context once at boot,
but we need to do it for all possible cpus.
This moves the context initialization to happen at boot time. With
this, we don't trash the refcount and the context never gets kfreed,
and we don't hit the BUG_ON.
Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Tested-by: Anton Blanchard <anton@samba.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
GFS2 tracks the number of revokes and unrevokes that are part of committed
transactions via sd_log_commited_revoke. It is possible for one process to add
revokes during its transaction, while another process unrevokes them during its
transaction. If the second process finishes its transaction first,
sd_log_commited_revoke will be decremented by the number of unrevokes that the
second process did, without first being incremented by the number of revokes
the first process did. This is fine, since all started transactions must be
completed before the journal can be flushed. However, sd_log_commited_revoke
is an unsigned integer, and log_refund() causes an assertion failure if it
would go negative at the end of a transaction. This patch makes
sd_log_commited_revoke a signed integer and allows it to go negative.
__gfs2_log_flush() still checks that it mataches the actual number of revokes.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
Now that the WM831x core has been converted to use genirq for the
interrupt controller there is no need for the client drivers to
use a WM831x-specific API rather than just calling genirq directly.
Also fixes a leak of the IRQ during init failure - the error path
free_irq() was using NULL rather than the driver data as the data
pointer so free_irq() wouldn't have matched.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Add wakeup support to the ads7846 driver. Platforms can enable wakeup
capability by setting the wakeup flag in ads7846_platform_data. With this
patch the ads7846 driver can be used to wake the system from suspend.
Signed-off-by: Ranjith Lohithakshan <ranjithl@ti.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
When reading data from Geyser 2 touchpads used on post Oct 2005 Apple
PowerBooks the driver was casting X and Y coordinates values to
'signed char'. Testing on one of such PowerBooks I have noticed that
touchpad always generates positive values, but some of them are greater
that 127, and thus, when cast to 'signed char' being interpreted as
a negative.
Such bigger values have been observed infrequently, closer to the
edges of a touchpad, so the problem was not very visible.
Nevertheless, the patch would potentially improve touchpad
driver accuracy.
Signed-off-by: Vadim Zaliva <lord@crocodile.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Fix memory leak and use kmalloc() instead of kzalloc() as we are going
to overwrite the allocated buffer.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Currently hardware with !IEEE80211_HW_PS_NULLFUNC_STACK and
IEEE80211_HW_REPORTS_TX_ACK_STATUS will never enter PSM due to the
conditions in the power save entry functions.
Fix those conditions.
Signed-off-by: Juuso Oikarinen <juuso.oikarinen@nokia.com>
Cc: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Fixed below compiler warning:
drivers/net/wireless/ipw2x00/ipw2200.c: In function ‘ipw_load_firmware’:
drivers/net/wireless/ipw2x00/ipw2200.c:3260: warning: the frame size of
1168 bytes is larger than 1024 bytes
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
we read the IQ correction values (i_cal and q_cal) for G mode from a wrong
location (the same shifts as for A mode is applied which is incorrect). use
correct locations, matching the docs and HAL sources.
also we should write IQ correction only when we have that information in the
EEPROM, starting from version 4. also write it in the same way as we do in the
periodic recalibration (enable last), just to be sure.
Signed-off-by: Bruno Randolf <br1@einfach.org>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
I/Q calibration was completely broken, resulting in a high number of CRC errors
on received packets. before i could see around 10% to 20% CRC errors, with this
patch they are between 0% and 3%.
1.) the removal of the mask in commit "ath5k: Fix I/Q calibration
(f1cf2dbd0f)" resulted in no mask beeing used
when writing the I/Q values into the register. additional errors in the
calculation of the values (see 2.) resulted too high numbers, exceeding the
masks, so wrong values like 0xfffffffe were written. to be safe we should
always use the bitmask when writing parts of a register.
2.) using a (s32) cast for q_coff is a wrong conversion to signed, since we
convert to a signed value later by substracting 128. this resulted in too low
numbers for Q many times, which were limited to -16 by the boundary check later
on.
3.) checked everything against the HAL sources and took over comments and minor
optimizations from there.
4.) we can't use ENABLE_BITS when we want to write a number (the number can
contain zeros). also always write the correction values first and set ENABLE
bit last, like the HAL does.
Signed-off-by: Bruno Randolf <br1@einfach.org>
Cc: stable@kernel.org
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
to reset the TSF, AR5K_BEACON_RESET_TSF has to be 1, not 0. also we have a
function for that so use it.
Signed-off-by: Bruno Randolf <br1@einfach.org>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
when using a fixed antenna we should use the antenna number in all tx
descriptors, otherwise the hardware will sometimes send the frame out on the
other antenna. it seems like the hardware does not always respect the default
antenna and diversity settings (esp. AR5K_STA_ID1_DEFAULT_ANTENNA).
also i would like to note that antenna diversity does not always work correctly
on 5414 (at least) when only one antenna is connected: for example all frames
might be received on antenna A but still the HW tries to send on antenna B some
times, causing packet loss.
this is both verified with the antenna statistics output of the previous patch
and a spectrum analyzer.
Signed-off-by: Bruno Randolf <br1@einfach.org>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
The ieee->networks consists of 128 struct libipw_network entries. If
we allocate this chunk of memory altogether, it ends up with an
order 4 page allocation. High order page allocation is likely to fail
on system high load. This patch splits the big chunk memory allocation
into small pieces, each is 344 bytes, allocates them with 128 times.
The patch fixed bug http://bugzilla.kernel.org/show_bug.cgi?id=14989
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Commit 34e895075e introduced sta_mtx
locking into sta_info_insert() (now sta_info_insert_rcu), but forgot
to unlock this mutex on one of the error paths. Fix this by adding
the missing mutex_unlock() call for the case where STA insert fails
due to an entry existing already. This may happen at least in AP mode
when a STA roams between two BSSes (vifs).
Signed-off-by: Jouni Malinen <j@w1.fi>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Remove the KSEG1ADDR define from rt2x00soc.h as it redefines and covers the
correct one from the arch/mips/include/asm/addrspace.h. Otherwise the driver
oopses on the target platform (Ralink rt3050 board).
Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
If the NFS_INO_REVAL_FORCED flag is set, that means that we don't yet have
an up to date attribute cache. Even if we hold a delegation, we must
put a GETATTR on the wire.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org
Some embedded ColdFire based boards use the SMC 91x family of ethernet
devices. (For example the Freescale M5249C3 and MoretonBay NETtel).
Add IO access support to the SMC91x driver, and allow this driver to
be configured for ColdFire platforms.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Setting new MAC address only worked when device was set to promiscuous mode.
Fix MAC address by writing new address to device using undocumented command
AX_CMD_READ_NODE_ID+1. Patch is tested with AX88772 device.
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Acked-by: David Hollis <dhollis@davehollis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit a43912ab19... ("tunnel: eliminate recursion field") eliminated
use of recursion field from tunnel structures, but its definition
still exists in ip6_tnl{}.
Let's remove that unused field.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 6e17d45a (net: add addr len check to dev_mc_add)
added a bug in dev_mc_add(), since it can now exit with a lock
imbalance.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Annotates neigh_invalidate() with __releases() and __acquires() for
sparse sake.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit d218d111 (tcp: Generalized TTL Security Mechanism) added a bug
for TIMEWAIT sockets. We should not test min_ttl for TW sockets.
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 09943a1819
Author: Matt Carlson <mcarlson@broadcom.com>
Date: Fri Aug 28 14:01:57 2009 +0000
tg3: Convert ISR parameter to tnapi
forgot to update tg3_poll_controller(), leading to intermittent crashes with
netpoll.
Fix this.
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Cc: stable@kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
Deactivate inbound checksumming on HiperSocket is a valid but
dangerous optimization in case the frame is routed from an OSA
network to an HiperSockets network. To go for sure we change the
default to software checksumming.
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Depending on their definition in z/VM, virtual devices for z/VM
VSWITCH or GuestLAN must be configured either in layer2 or in
layer3 mode. If qeth detects a layer mismatch, device activation
fails. Trying to recover from this error cannot help; thus
scheduling a recovery should be avoided.
In addition, since recovery is forbidden during online setting of
a qeth device, existence of its network device is guaranteed for all
dev_close() calls in qeth. The corresponding checks can be removed.
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If HiperSockets Network Traffic Analyzer is switched off, but trace
disabling fails somehow, the qeth driver does not switch off its
promisc mode status. A following sniffer reactivation fails, since
qeth does not see a need to reenable tracing.
At the same time the code analyzing results of trace commands is
restructured.
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
dhcp frames are valid IPv4 packets so there is no need to send them
in pass thru mode. This allows dhcp packets to pass HiperSockets.
Also the dhcp release frame is send out correctly with this patch.
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
provide qeth kmsg definitions to enable hash string generation for
kernel message created with dev_err().
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reinstates the lost unpressing of BTN_TOUCH. To prevent undesireably
touch toggles this also deals with tip switch events.
Added a trap to prevent going out of bounds for hidinputs with empty reports.
Clear bits of unused buttons which result in misidentification.
Signed-off-by: Rafi Rubin <rafi@seas.upenn.edu>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Drop the obsolete "profile" naming used by perf for trace events.
Perf can now do more than simple events counting, so generalize
the API naming.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
We are taking a wrong regs snapshot when a trace event triggers.
Either we use get_irq_regs(), which gives us the interrupted
registers if we are in an interrupt, or we use task_pt_regs()
which gives us the state before we entered the kernel, assuming
we are lucky enough to be no kernel thread, in which case
task_pt_regs() returns the initial set of regs when the kernel
thread was started.
What we want is different. We need a hot snapshot of the regs,
so that we can get the instruction pointer to record in the
sample, the frame pointer for the callchain, and some other
things.
Let's use the new perf_fetch_caller_regs() for that.
Comparison with perf record -e lock: -R -a -f -g
Before:
perf [kernel] [k] __do_softirq
|
--- __do_softirq
|
|--55.16%-- __open
|
--44.84%-- __write_nocancel
After:
perf [kernel] [k] perf_tp_event
|
--- perf_tp_event
|
|--41.07%-- lock_acquire
| |
| |--39.36%-- _raw_spin_lock
| | |
| | |--7.81%-- hrtimer_interrupt
| | | smp_apic_timer_interrupt
| | | apic_timer_interrupt
The old case was producing unreliable callchains. Now having
right frame and instruction pointers, we have the trace we
want.
Also syscalls and kprobe events already have the right regs,
let's use them instead of wasting a retrieval.
v2: Follow the rename perf_save_regs() -> perf_fetch_caller_regs()
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Archs <linux-arch@vger.kernel.org>
Events that trigger overflows by interrupting a context can
use get_irq_regs() or task_pt_regs() to retrieve the state
when the event triggered. But this is not the case for some
other class of events like trace events as tracepoints are
executed in the same context than the code that triggered
the event.
It means we need a different api to capture the regs there,
namely we need a hot snapshot to get the most important
informations for perf: the instruction pointer to get the
event origin, the frame pointer for the callchain, the code
segment for user_mode() tests (we always use __KERNEL_CS as
trace events always occur from the kernel) and the eflags
for further purposes.
v2: rename perf_save_regs to perf_fetch_caller_regs as per
Masami's suggestion.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Archs <linux-arch@vger.kernel.org>
We were using the frame pointer based stack walker on every
contexts in x86-32, but not in x86-64 where we only use the
seven-league boots on the exception stacks.
Use it also on irq and process stacks. This utterly accelerate
the captures.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
