Using context bit recursion checking, we can help increase the
performance of the ring buffer.
Before this patch:
# echo function > /debug/tracing/current_tracer
# for i in `seq 10`; do ./hackbench 50; done
Time: 10.285
Time: 10.407
Time: 10.243
Time: 10.372
Time: 10.380
Time: 10.198
Time: 10.272
Time: 10.354
Time: 10.248
Time: 10.253
(average: 10.3012)
Now we have:
# echo function > /debug/tracing/current_tracer
# for i in `seq 10`; do ./hackbench 50; done
Time: 9.712
Time: 9.824
Time: 9.861
Time: 9.827
Time: 9.962
Time: 9.905
Time: 9.886
Time: 10.088
Time: 9.861
Time: 9.834
(average: 9.876)
a 4% savings!
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The function tracer had two different versions of function tracing.
The disabling of irqs version and the preempt disable version.
As function tracing in very intrusive and can cause nasty recursion
issues, it has its own recursion protection. But the old method to
do this was a flat layer. If it detected that a recursion was happening
then it would just return without recording.
This made the preempt version (much faster than the irq disabling one)
not very useful, because if an interrupt were to occur after the
recursion flag was set, the interrupt would not be traced at all,
because every function that was traced would think it recursed on
itself (due to the context it preempted setting the recursive flag).
Now that we have a recursion flag for every context level, we
no longer need to worry about that. We can disable preemption,
set the current context recursion check bit, and go on. If an
interrupt were to come along, it would check its own context bit
and happily continue to trace.
As the preempt version is faster than the irq disable version,
there's no more reason to keep the preempt version around.
And the irq disable version still had an issue with missing
out on tracing NMI code.
Remove the irq disable function tracer version and have the
preempt disable version be the default (and only version).
Before this patch we had from running:
# echo function > /debug/tracing/current_tracer
# for i in `seq 10`; do ./hackbench 50; done
Time: 12.028
Time: 11.945
Time: 11.925
Time: 11.964
Time: 12.002
Time: 11.910
Time: 11.944
Time: 11.929
Time: 11.941
Time: 11.924
(average: 11.9512)
Now we have:
# echo function > /debug/tracing/current_tracer
# for i in `seq 10`; do ./hackbench 50; done
Time: 10.285
Time: 10.407
Time: 10.243
Time: 10.372
Time: 10.380
Time: 10.198
Time: 10.272
Time: 10.354
Time: 10.248
Time: 10.253
(average: 10.3012)
a 13.8% savings!
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When function tracing occurs, the following steps are made:
If arch does not support a ftrace feature:
call internal function (uses INTERNAL bits) which calls...
If callback is registered to the "global" list, the list
function is called and recursion checks the GLOBAL bits.
then this function calls...
The function callback, which can use the FTRACE bits to
check for recursion.
Now if the arch does not suppport a feature, and it calls
the global list function which calls the ftrace callback
all three of these steps will do a recursion protection.
There's no reason to do one if the previous caller already
did. The recursion that we are protecting against will
go through the same steps again.
To prevent the multiple recursion checks, if a recursion
bit is set that is higher than the MAX bit of the current
check, then we know that the check was made by the previous
caller, and we can skip the current check.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Currently for recursion checking in the function tracer, ftrace
tests a task_struct bit to determine if the function tracer had
recursed or not. If it has, then it will will return without going
further.
But this leads to races. If an interrupt came in after the bit
was set, the functions being traced would see that bit set and
think that the function tracer recursed on itself, and would return.
Instead add a bit for each context (normal, softirq, irq and nmi).
A check of which context the task is in is made before testing the
associated bit. Now if an interrupt preempts the function tracer
after the previous context has been set, the interrupt functions
can still be traced.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There is lots of places that perform:
op = rcu_dereference_raw(ftrace_control_list);
while (op != &ftrace_list_end) {
Add a helper macro to do this, and also optimize for a single
entity. That is, gcc will optimize a loop for either no iterations
or more than one iteration. But usually only a single callback
is registered to the function tracer, thus the optimized case
should be a single pass. to do this we now do:
op = rcu_dereference_raw(list);
do {
[...]
} while (likely(op = rcu_dereference_raw((op)->next)) &&
unlikely((op) != &ftrace_list_end));
An op is always registered (ftrace_list_end when no callbacks is
registered), thus when a single callback is registered, the link
list looks like:
top => callback => ftrace_list_end => NULL.
The likely(op = op->next) still must be performed due to the race
of removing the callback, where the first op assignment could
equal ftrace_list_end. In that case, the op->next would be NULL.
But this is unlikely (only happens in a race condition when
removing the callback).
But it is very likely that the next op would be ftrace_list_end,
unless more than one callback has been registered. This tells
gcc what the most common case is and makes the fast path with
the least amount of branches.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The function tracing recursion self test should not crash
the machine if the resursion test fails. If it detects that
the function tracing is recursing when it should not be, then
bail, don't go into an infinite recursive loop.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If one of the function tracers set by the global ops is not recursion
safe, it can still be called directly without the added recursion
supplied by the ftrace infrastructure.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The test that checks function recursion does things differently
if the arch does not support all ftrace features. But that really
doesn't make a difference with how the test runs, and either way
the count variable should be 2 at the end.
Currently the test wrongly fails for archs that don't support all
the ftrace features.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There's a race condition between the setting of a new tracer and
the update of the max trace buffers (the swap). When a new tracer
is added, it sets current_trace to nop_trace before disabling
the old tracer. At this moment, if the old tracer uses update_max_tr(),
the update may trigger the warning against !current_trace->use_max-tr,
as nop_trace doesn't have that set.
As update_max_tr() requires that interrupts be disabled, we can
add a check to see if current_trace == nop_trace and bail if it
does. Then when disabling the current_trace, set it to nop_trace
and run synchronize_sched(). This will make sure all calls to
update_max_tr() have completed (it was called with interrupts disabled).
As a clean up, this commit also removes shrinking and recreating
the max_tr buffer if the old and new tracers both have use_max_tr set.
The old way use to always shrink the buffer, and then expand it
for the next tracer. This is a waste of time.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This reverts commit eccf2979b2.
The reason is that it broke TI WiLink shared transport on Panda.
Also, callback functions should not be added to board files anymore,
so revert to implementing the power functions in the driver itself.
Additionally, changed a variable name ('status' to 'err') so that this
revert compiles properly.
Cc: stable <stable@vger.kernel.org> [3.7]
Acked-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Luciano Coelho <coelho@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Hotplug
PCI: pciehp: Use per-slot workqueues to avoid deadlock
PCI: shpchp: Make shpchp_wq non-ordered
PCI: shpchp: Handle push button event asynchronously
PCI: shpchp: Use per-slot workqueues to avoid deadlock
Power management
PCI: Allow pcie_aspm=force even when FADT indicates it is unsupported
Misc
PCI/AER: pci_get_domain_bus_and_slot() call missing required pci_dev_put()
PCI: remove depends on CONFIG_EXPERIMENTAL
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Merge tag '3.8-pci-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull PCI updates from Bjorn Helgaas:
"The most important is a fix for a pciehp deadlock that occurs when
unplugging a Thunderbolt adapter. We also applied the same fix to
shpchp, removed CONFIG_EXPERIMENTAL dependencies, fixed a
pcie_aspm=force problem, and fixed a refcount leak.
Details:
- Hotplug
PCI: pciehp: Use per-slot workqueues to avoid deadlock
PCI: shpchp: Make shpchp_wq non-ordered
PCI: shpchp: Handle push button event asynchronously
PCI: shpchp: Use per-slot workqueues to avoid deadlock
- Power management
PCI: Allow pcie_aspm=force even when FADT indicates it is unsupported
- Misc
PCI/AER: pci_get_domain_bus_and_slot() call missing required pci_dev_put()
PCI: remove depends on CONFIG_EXPERIMENTAL"
* tag '3.8-pci-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
PCI: remove depends on CONFIG_EXPERIMENTAL
PCI: Allow pcie_aspm=force even when FADT indicates it is unsupported
PCI: shpchp: Use per-slot workqueues to avoid deadlock
PCI: shpchp: Handle push button event asynchronously
PCI: shpchp: Make shpchp_wq non-ordered
PCI/AER: pci_get_domain_bus_and_slot() call missing required pci_dev_put()
PCI: pciehp: Use per-slot workqueues to avoid deadlock
Commit 083b804c4d ("async: use workqueue for worker pool") made it
possible that async jobs are moved from pending to running out-of-order.
While pending async jobs will be queued and dispatched for execution in
the same order, nothing guarantees they'll enter "1) move self to the
running queue" of async_run_entry_fn() in the same order.
Before the conversion, async implemented its own worker pool. An async
worker, upon being woken up, fetches the first item from the pending
list, which kept the executing lists sorted. The conversion to
workqueue was done by adding work_struct to each async_entry and async
just schedules the work item. The queueing and dispatching of such work
items are still in order but now each worker thread is associated with a
specific async_entry and moves that specific async_entry to the
executing list. So, depending on which worker reaches that point
earlier, which is non-deterministic, we may end up moving an async_entry
with larger cookie before one with smaller one.
This broke __lowest_in_progress(). running->domain may not be properly
sorted and is not guaranteed to contain lower cookies than pending list
when not empty. Fix it by ensuring sort-inserting to the running list
and always looking at both pending and running when trying to determine
the lowest cookie.
Over time, the async synchronization implementation became quite messy.
We better restructure it such that each async_entry is linked to two
lists - one global and one per domain - and not move it when execution
starts. There's no reason to distinguish pending and running. They
behave the same for synchronization purposes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
. revert 20b279 - require exclude_guest to use PEBS - kernel side,
now older binaries will continue working for things like cycles:pp
without needing to pass extra modifiers, from David Ahern.
. Fix building from 'make perf-*-src-pkg' tarballs, broken by UAPI, from
Sebastian Andrzej Siewior
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux
Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
. revert 20b279 - require exclude_guest to use PEBS - kernel side, now
older binaries will continue working for things like cycles:pp
without needing to pass extra modifiers, from David Ahern.
. Fix building from 'make perf-*-src-pkg' tarballs, broken by UAPI,
from Sebastian Andrzej Siewior
[ Pulling directly, Ingo would normally pull but has been unresponsive ]
* tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
perf tools: Fix building from 'make perf-*-src-pkg' tarballs
perf x86: revert 20b279 - require exclude_guest to use PEBS - kernel side
Pull parisc fixes from Helge Deller:
"Improve the stability of the linux kernel on the parisc architecture"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: sigaltstack doesn't round ss.ss_sp as required
parisc: improve ptrace support for gdb single-step
parisc: don't claim cpu irqs more than once
parisc: avoid undefined shift in cnv_float.h
Pull fuse fixes from Miklos Szeredi:
"This contain a bugfix for CUSE and miscellaneous small fixes"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse:
fuse: remove unused variable in fuse_try_move_page()
fuse: make fuse_file_fallocate() static
fuse: Move CUSE Kconfig entry from fs/Kconfig into fs/fuse/Kconfig
cuse: fix uninitialized variable warnings
cuse: do not register multiple devices with identical names
cuse: use mutex as registration lock instead of spinlocks
- Remove a bad #include from the Samsung driver
- Some Kconfig hazzle for the Samsungs
- Skip gpiolib registration on EXYNOS5440
- Don't free the MVEBU label
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Merge tag 'fixes-for-v3.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio
Pull GPIO fixes from Linus Walleij:
"Here are some GPIO fixes I stacked up in my GPIO tree:
- Remove a bad #include from the Samsung driver
- Some Kconfig hazzle for the Samsungs
- Skip gpiolib registration on EXYNOS5440
- Don't free the MVEBU label"
* tag 'fixes-for-v3.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio:
gpio: mvebu: Don't free chip label memory
gpio: samsung: skip gpio lib registration for EXYNOS5440
gpio: samsung: silent build warning for EXYNOS5 SoCs
gpio: samsung: fix pinctrl condition for exynos and exynos5440
gpio: samsung: remove inclusion <mach/regs-clock.h>
o Support swap file and link generic_file_remap_pages
o Enhance the bio streaming flow and free section control
o Major bug fix on recovery routine
o Minor bug/warning fixes and code cleanups
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Merge tag 'f2fs-for-3.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs
Pull f2fs fixes from Jaegeuk Kim:
o Support swap file and link generic_file_remap_pages
o Enhance the bio streaming flow and free section control
o Major bug fix on recovery routine
o Minor bug/warning fixes and code cleanups
* tag 'f2fs-for-3.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (22 commits)
f2fs: use _safe() version of list_for_each
f2fs: add comments of start_bidx_of_node
f2fs: avoid issuing small bios due to several dirty node pages
f2fs: support swapfile
f2fs: add remap_pages as generic_file_remap_pages
f2fs: add __init to functions in init_f2fs_fs
f2fs: fix the debugfs entry creation path
f2fs: add global mutex_lock to protect f2fs_stat_list
f2fs: remove the blk_plug usage in f2fs_write_data_pages
f2fs: avoid redundant time update for parent directory in f2fs_delete_entry
f2fs: remove redundant call to set_blocksize in f2fs_fill_super
f2fs: move f2fs_balance_fs to punch_hole
f2fs: add f2fs_balance_fs in several interfaces
f2fs: revisit the f2fs_gc flow
f2fs: check return value during recovery
f2fs: avoid null dereference in f2fs_acl_from_disk
f2fs: initialize newly allocated dnode structure
f2fs: update f2fs partition info about SIT/NAT layout
f2fs: update f2fs document to reflect SIT/NAT layout correctly
f2fs: remove unneeded INIT_LIST_HEAD at few places
...
is placed on a function mcount/nop location, and the arch supports it,
instead of adding a breakpoint, kprobes will register a function callback
as that is much more efficient.
The function tracer requires to update modules before they run, and
uses the module notifier to do so. But if something else in the module
notifiers registers a kprobe at one of these locations, before ftrace
can get to it, then the system could fail.
The function tracer must be initialized early, otherwise module notifiers
that probe will only work by chance.
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Merge tag 'trace-3.8-rc4-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fix from Steven Rostedt:
"Kprobes now uses the function tracer if it can. That is, if a probe
is placed on a function mcount/nop location, and the arch supports it,
instead of adding a breakpoint, kprobes will register a function
callback as that is much more efficient.
The function tracer requires to update modules before they run, and
uses the module notifier to do so. But if something else in the
module notifiers registers a kprobe at one of these locations, before
ftrace can get to it, then the system could fail.
The function tracer must be initialized early, otherwise module
notifiers that probe will only work by chance."
* tag 'trace-3.8-rc4-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Be first to run code modification on modules
Thought: I wonder if sparse could have caught this, somehow.
2) ahci: support a slightly odd Enmotus variant
3) core: fix a drive detection problem by correcting the logic
by which the DevSlp timing variables are obtained and used.
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Merge tag 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev
Pull libata fixes from Jeff Garzik:
1) ahci: Fix typo that caused erronenous error handling.
Thought: I wonder if sparse could have caught this, somehow.
2) ahci: support a slightly odd Enmotus variant
3) core: fix a drive detection problem by correcting the logic by which
the DevSlp timing variables are obtained and used.
* tag 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
[libata] replace sata_settings with devslp_timing
[libata] ahci: Add support for Enmotus Bobcat device.
[libata] ahci: Fix lack of command retry after a success error handler.
Pull security subsystem bugfixes from James Morris.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
security/device_cgroup: lock assert fails in dev_exception_clean()
evm: checking if removexattr is not a NULL
wake_up_process() should never wakeup a TASK_STOPPED/TRACED task.
Change it to use TASK_NORMAL and add the WARN_ON().
TASK_ALL has no other users, probably can be killed.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
putreg() assumes that the tracee is not running and pt_regs_access() can
safely play with its stack. However a killed tracee can return from
ptrace_stop() to the low-level asm code and do RESTORE_REST, this means
that debugger can actually read/modify the kernel stack until the tracee
does SAVE_REST again.
set_task_blockstep() can race with SIGKILL too and in some sense this
race is even worse, the very fact the tracee can be woken up breaks the
logic.
As Linus suggested we can clear TASK_WAKEKILL around the arch_ptrace()
call, this ensures that nobody can ever wakeup the tracee while the
debugger looks at it. Not only this fixes the mentioned problems, we
can do some cleanups/simplifications in arch_ptrace() paths.
Probably ptrace_unfreeze_traced() needs more callers, for example it
makes sense to make the tracee killable for oom-killer before
access_process_vm().
While at it, add the comment into may_ptrace_stop() to explain why
ptrace_stop() still can't rely on SIGKILL and signal_pending_state().
Reported-by: Salman Qazi <sqazi@google.com>
Reported-by: Suleiman Souhlal <suleiman@google.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
By popular demand, arch/aarch64 is now known as arch/arm64. However,
uname -m (and indeed the GNU triplet) still use aarch64 as the machine
string.
This patch fixes native builds of both the kernel and perf tools by
updating the relevant Makefiles to munge the output of uname -m and
set the ARCH variable appropriately.
Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The kernel's internal definition of ELF_NGREG uses struct pt_regs, which
means that we disagree with userspace on the size of coredumps since
glibc correctly uses the user-visible struct user_pt_regs.
This patch fixes our ELF_NGREG definition to use struct user_pt_regs
and introduces our own ELF_CORE_COPY_REGS to convert between the user
and kernel structure definitions.
Cc: <stable@vger.kernel.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This patch (as1642) adds an ehci->priv field for private use by EHCI
platform drivers. The space was provided some time ago, but it didn't
have a name.
Until now none of the platform drivers has used this private space,
but that's about to change in the next patch of this series.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1641) fixes a minor bug in ehci-hcd left over from when
the Chipidea driver was converted to the "ehci-hcd is a library"
scheme. The test for whether the Chipidea platform driver is active
should be IS_ENABLED(), not defined().
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Without this, platform drivers e.g. ehci-omap.c will see a
different version of struct ehci_hcd than ehci-hcd.c and
break reference to 'debug_dir' and 'priv' members when
CONFIG_USB_DEBUG is enabled.
Signed-off-by: Roger Quadros <rogerq@ti.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As trace_clock is used by other things besides tracing, and it
does not require anything from trace.h, it is best not to include
the header file in trace_clock.c.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch (as1644) fixes a race that occurs during startup in
uhci-hcd. If the IRQ line is shared with other devices, it's possible
for the handler routine to be called before the data structures are
fully initialized.
The problem is fixed by adding a check to the IRQ handler routine. If
the initialization hasn't finished yet, the routine will return
immediately.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Don Zickus <dzickus@redhat.com>
Tested-by: "Huang, Adrian (ISS Linux TW)" <adrian.huang@hp.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cleanup and preparation for the next change.
signal_wake_up(resume => true) is overused. None of ptrace/jctl callers
actually want to wakeup a TASK_WAKEKILL task, but they can't specify the
necessary mask.
Turn signal_wake_up() into signal_wake_up_state(state), reintroduce
signal_wake_up() as a trivial helper, and add ptrace_signal_wake_up()
which adds __TASK_TRACED.
This way ptrace_signal_wake_up() can work "inside" ptrace_request()
even if the tracee doesn't have the TASK_WAKEKILL bit set.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Due to a userspace issue with PowerTop v2beta, which hardcoded
the offset of event fields that it was using, it broke when
we removed the Big Kernel Lock counter from the event header.
(commit e6e1e2593 "tracing: Remove lock_depth from event entry")
Because this broke userspace, it was determined that we must
keep those 4 bytes around.
(commit a3a4a5acd "Regression: partial revert "tracing: Remove lock_depth from event entry"")
This unfortunately wastes space in the ring buffer. 4 bytes per
event, where a lot of events are just 24 bytes. That's 16% of the
buffer wasted. A million events will add 4 megs of white space
into the buffer.
It was later noticed that PowerTop v2beta could not work on systems
where the kernel was 64 bit but the userspace was 32 bits.
The reason was because the offsets are different between the
two and the hard coded offset of one would not work with the other.
With PowerTop v2 final, it implemented the same interface that both
perf and trace-cmd use. That is, it reads the format file of
the event to find the offsets of the fields it needs. This fixes
the problem with running powertop on a 32 bit userspace running
on a 64 bit kernel. It also no longer requires the 4 byte padding.
As PowerTop v2 has been out for a while, and is included in all
major distributions, it is time that we can safely remove the
4 bytes of padding. Users of PowerTop v2beta should upgrade to
PowerTop v2 final.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This is calling list_del() inside a loop which is a problem when we try
move to the next item on the list. I've converted it to use the _safe
version. And also, as a cleanup, I've converted it to use
list_for_each_entry instead of list_for_each.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
The caller of start_bidx_of_node() should give proper node offsets which
point only direct node blocks. Otherwise, it is a caller's bug.
This patch adds comments to make it clear.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
If some small bios of dirty node pages are supposed to be issued during the
sequential data writes, there-in well-produced consecutive data bios are able
to be split by the small node bios, resulting in performance degradation.
So, let's collect a number of dirty node pages until reaching a threshold.
And, by default, I set the threshold as 2MB, a segment size.
This improves sequential write performance on i5, 512GB SSD (830 w/ SATA2) as
follows.
Before: 231 MB/s -> After: 255 MB/s
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Reviewed-by: Namjae Jeon <namjae.jeon@samsung.com>
This patch adds f2fs_bmap operation to the data address space.
This enables f2fs to support swapfile.
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
This was added for all the file systems before.
See the following commit.
commit id: 0b173bc4da
[PATCH] mm: kill vma flag VM_CAN_NONLINEAR
This patch moves actual ptes filling for non-linear file mappings
into special vma operation: ->remap_pages().
File system must implement this method to get non-linear mappings support,
if it uses filemap_fault() then generic_file_remap_pages() can be used.
Now device drivers can implement this method and obtain nonlinear vma support."
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Add __init to functions in init_f2fs_fs for code consistency.
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>
Finally we have a build fix for fsl-mxc-udc UDC driver.
We also have a fix for ep0 maxburst setting on DWC3
which could confuse the HW if we tell it we had way
too many streams on that endpoint when it _has_ to be
only one.
cppi_dma support for MUSB got a fix when running as a
module. By dropping the wrong __init annotation, the
function will be available even when we're modules and
we're done with .init.text section.
Last, but not least, we have a fix on FunctionFS which
was causing a bug on our option parsing algorithm.
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Merge tag 'fixes-for-v3.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb into usb-linus
Felipe writes:
usb: fixes for v3.8-rc5
Finally we have a build fix for fsl-mxc-udc UDC driver.
We also have a fix for ep0 maxburst setting on DWC3
which could confuse the HW if we tell it we had way
too many streams on that endpoint when it _has_ to be
only one.
cppi_dma support for MUSB got a fix when running as a
module. By dropping the wrong __init annotation, the
function will be available even when we're modules and
we're done with .init.text section.
Last, but not least, we have a fix on FunctionFS which
was causing a bug on our option parsing algorithm.
Move SAVE_REGS support flag into Kconfig and rename
it to CONFIG_DYNAMIC_FTRACE_WITH_REGS. This also introduces
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS which indicates
the architecture depending part of ftrace has a code
that saves full registers.
On the other hand, CONFIG_DYNAMIC_FTRACE_WITH_REGS indicates
the code is enabled.
Link: http://lkml.kernel.org/r/20120928081516.3560.72534.stgit@ltc138.sdl.hitachi.co.jp
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Add the file max_graph_depth to the debug tracing directory that lets
the user define the depth of the function graph.
A very useful operation is to set the depth to 1. Then it traces only
the first function that is called when entering the kernel. This can
be used to determine what system operations interrupt a process.
For example, to work on NOHZ processes (single tasks running without
a timer tick), if any interrupt goes off and preempts that task, this
code will show it happening.
# cd /sys/kernel/debug/tracing
# echo 1 > max_graph_depth
# echo function_graph > current_tracer
# cat per_cpu/cpu/<cpu-of-process>/trace
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
When function tracing with either debug locks enabled or tracing
preempt disabled, the add_preempt_count() is traced. This is an
issue with lockdep and function tracing. As function tracing
can disable interrupts, and lockdep records that change,
lockdep may not be able to handle this recursion if it happens from
an NMI context.
The first thing that an NMI does is:
#define nmi_enter() \
do { \
ftrace_nmi_enter(); \
BUG_ON(in_nmi()); \
add_preempt_count(NMI_OFFSET + HARDIRQ_OFFSET); \
lockdep_off(); \
rcu_nmi_enter(); \
trace_hardirq_enter(); \
} while (0)
When the add_preempt_count() is traced, and the tracing callback
disables interrupts, it will jump into the lockdep code. There's
some places in lockdep that can't handle this re-entrance, and
causes lockdep to fail.
As the lockdep_off() (and lockdep_on) is a simple:
void lockdep_off(void)
{
current->lockdep_recursion++;
}
and is never traced, it can be called first in nmi_enter()
and lockdep_on() last in nmi_exit().
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
There's now a check in tracing_reset_online_cpus() if the buffer is
allocated or NULL. No need to do a check before calling it with max_tr.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
max_tr->buffer could be NULL in the tracing_reset{_online_cpus}. In this
case, a NULL pointer dereference happens, so we should return immediately
from these functions.
Note, the current code does not call tracing_reset*() with max_tr when
its buffer is NULL, but future code will. This patch is needed to prevent
the future code from crashing.
Link: http://lkml.kernel.org/r/20121219070234.31200.93863.stgit@liselsia
Signed-off-by: Hiraku Toyooka <hiraku.toyooka.gu@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Some functions in the syscall tracing is used only locally to
the file, but they are labeled global. Convert them to static functions.
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Without this patch, we can register a uprobe event for a directory.
Enabling such a uprobe event would anyway fail.
Example:
$ echo 'p /bin:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events
However dirctories cannot be valid targets for uprobe.
Hence verify if the target is a regular file during the probe
registration.
Link: http://lkml.kernel.org/r/20130103004212.690763002@goodmis.org
Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
[ cleaned up whitespace and removed redundant IS_DIR() check ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
typeof(&buffer) is a pointer to array of 1024 char, or char (*)[1024].
But, typeof(&buffer[0]) is a pointer to char which match the return type of get_trace_buf().
As well-known, the value of &buffer is equal to &buffer[0].
so return this_cpu_ptr(&percpu_buffer->buffer[0]) can avoid type cast.
Link: http://lkml.kernel.org/r/50A1A800.3020102@gmail.com
Reviewed-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Shan Wei <davidshan@tencent.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Steven Rostedt