Commit Graph

27802 Commits

Author SHA1 Message Date
Linus Torvalds
fe250923bb Merge tag 'usb-3.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
USB fixes for 3.3-rc3

Here are a few minor USB fixes and a bunch of device id updates for the
USB drivers.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

* tag 'usb-3.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  USB: usbserial: add new PID number (0xa951) to the ftdi driver
  usb: ch9.h: usb_endpoint_maxp() uses __le16_to_cpu()
  usb: musb: fix a build error on mips
  uwb & wusb & usb wireless controllers: fix kconfig error & build errors
  usb: Skip PCI USB quirk handling for Netlogic XLP
  powerpc/usb: fix issue of CPU halt when missing USB PHY clock
  usb: otg: mv_otg: Add dependence
  usb: host: Distinguish Kconfig text for Freescale controllers
  USB: add new zte 3g-dongle's pid to option.c
  usb: ch9.h: usb_endpoint_maxp() uses __le16_to_cpu()
  USB: qcserial: don't enable autosuspend
  USB: qcserial: add several new serial devices
  usb: otg: mv_otg: Add dependence
  usb: gadget: zero: fix bug in loopback autoresume handling
2012-02-09 13:50:54 -08:00
Linus Torvalds
abaaf3e12c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-2.6:
  mfd: Avoid twl6040-codec PLL reconfiguration when not needed
  mfd: Store twl6040-codec mclk configuration
2012-02-07 14:05:49 -08:00
Heiko Carstens
96e02d1586 exec: fix use-after-free bug in setup_new_exec()
Setting the task name is done within setup_new_exec() by accessing
bprm->filename. However this happens after flush_old_exec().
This may result in a use after free bug, flush_old_exec() may
"complete" vfork_done, which will wake up the parent which in turn
may free the passed in filename.
To fix this add a new tcomm field in struct linux_binprm which
contains the now early generated task name until it is used.

Fixes this bug on s390:

  Unable to handle kernel pointer dereference at virtual kernel address 0000000039768000
  Process kworker/u:3 (pid: 245, task: 000000003a3dc840, ksp: 0000000039453818)
  Krnl PSW : 0704000180000000 0000000000282e94 (setup_new_exec+0xa0/0x374)
  Call Trace:
  ([<0000000000282e2c>] setup_new_exec+0x38/0x374)
   [<00000000002dd12e>] load_elf_binary+0x402/0x1bf4
   [<0000000000280a42>] search_binary_handler+0x38e/0x5bc
   [<0000000000282b6c>] do_execve_common+0x410/0x514
   [<0000000000282cb6>] do_execve+0x46/0x58
   [<00000000005bce58>] kernel_execve+0x28/0x70
   [<000000000014ba2e>] ____call_usermodehelper+0x102/0x140
   [<00000000005bc8da>] kernel_thread_starter+0x6/0xc
   [<00000000005bc8d4>] kernel_thread_starter+0x0/0xc
  Last Breaking-Event-Address:
   [<00000000002830f0>] setup_new_exec+0x2fc/0x374

  Kernel panic - not syncing: Fatal exception: panic_on_oops

Reported-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-06 15:15:20 -08:00
Linus Torvalds
23783f817b Merge tag 'pm-fixes-for-3.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Power management fixes for 3.3-rc3

Three power management regression fixes, one for a recent regression introcuded
by the freezer changes during the 3.3 merge window and two for regressions
in cpuidle (resulting from PM QoS changes) and in the hibernate user space
interface, both introduced during the 3.2 development cycle.

They include:

* Two hibernate (s2disk) regression fixes from Srivatsa S. Bhat (for
 regressions introduced during the 3.3 merge window and during the 3.2
 development cycle).

* A cpuidle fix from Venki Pallipadi for a regression resulting from PM QoS
 changes during the 3.2 development cycle causing cpuidle to work incorrectly
 for CONFIG_PM unset.

* tag 'pm-fixes-for-3.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / QoS: CPU C-state breakage with PM Qos change
  PM / Freezer: Thaw only kernel threads if freezing of kernel threads fails
  PM / Hibernate: Thaw kernel threads in SNAPSHOT_CREATE_IMAGE ioctl path
2012-02-04 15:21:39 -08:00
Venkatesh Pallipadi
d020283dc6 PM / QoS: CPU C-state breakage with PM Qos change
Looks like change "PM QoS: Move and rename the implementation files"
merged during the 3.2 development cycle made PM QoS depend on
CONFIG_PM which depends on (PM_SLEEP || PM_RUNTIME).

That breaks CPU C-states with kernels not having these CONFIGs, causing CPUs
to spend time in Polling loop idle instead of going into deep C-states,
consuming way way more power. This is with either acpi idle or intel idle
enabled.

Either CONFIG_PM should be enabled with any pm_qos users or
the !CONFIG_PM pm_qos_request() should return sane defaults not to break
the existing users. Here's is the patch for the latter option.

[rjw: Modified the changelog slightly.]

Signed-off-by: Venkatesh Pallipadi <venki@google.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@vger.kernel.org
2012-02-04 22:23:17 +01:00
Linus Torvalds
31c150a11c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: i8042 - add Lenovo Ideapad U455 to 'reset' blacklist
  Input: serio_raw - return proper result when serio_raw_read fails
  Input: document device properties
  Input: twl4030_keypad - fix comment (trivial)
  Input: gpio_keys - fix struct device declared inside parameter list
  Input: evdev - fix variable initialisation
2012-02-04 10:57:42 -08:00
Linus Torvalds
4554c135a0 Merge branch 'fixes' of git://git.infradead.org/users/vkoul/slave-dma
* 'fixes' of git://git.infradead.org/users/vkoul/slave-dma:
  i.MX SDMA: Fix burstsize settings
  ARM: mach-shmobile: both USB DMAC instances on sh7372 are slave-only
  dma: sh_dma: not all SH DMAC implementations support MEMCPY
  at_hdmac: bugfix for enabling channel irq
  dmaengine: fix missing 'cnt' in ?: in dmatest
2012-02-04 10:54:26 -08:00
Linus Torvalds
71b1b20b8a Merge tag 'for-linus-3.3' of git://git.infradead.org/~dwmw2/mtd-3.3
- Fix a regression in 16-bit Atmel NAND flash which was introduced in 3.1
 - Fix breakage with MTD suspend caused by the API rework
 - Fix a problem with resetting the MX28 BCH module
 - A couple of other trivial fixes

* tag 'for-linus-3.3-20120204' of git://git.infradead.org/~dwmw2/mtd-3.3:
  Revert "mtd: atmel_nand: optimize read/write buffer functions"
  mtd: fix MTD suspend
  jffs2: do not initialize variable unnecessarily
  mtd: gpmi-nand bugfix: reset the BCH module when it is not MX23
  mtd: nand: fix typo in comment
2012-02-04 07:17:47 -08:00
Peter Ujfalusi
f8447d6c21 mfd: Store twl6040-codec mclk configuration
Store the last used mclk configuration for the PLL.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2012-02-03 19:03:44 +01:00
Josh Triplett
ff05f603c3 include/linux/lp8727.h: Remove executable bit
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-02 15:43:40 -08:00
Christopher Yeoh
8cdb878dcb Fix race in process_vm_rw_core
This fixes the race in process_vm_core found by Oleg (see

  http://article.gmane.org/gmane.linux.kernel/1235667/

for details).

This has been updated since I last sent it as the creation of the new
mm_access() function did almost exactly the same thing as parts of the
previous version of this patch did.

In order to use mm_access() even when /proc isn't enabled, we move it to
kernel/fork.c where other related process mm access functions already
are.

Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-02 12:55:17 -08:00
Linus Torvalds
2f2fde9272 Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus', 'sched-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  bugs, x86: Fix printk levels for panic, softlockups and stack dumps

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf top: Fix number of samples displayed
  perf tools: Fix strlen() bug in perf_event__synthesize_event_type()
  perf tools: Fix broken build by defining _GNU_SOURCE in Makefile
  x86/dumpstack: Remove unneeded check in dump_trace()
  perf: Fix broken interrupt rate throttling

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/rt: Fix task stack corruption under __ARCH_WANT_INTERRUPTS_ON_CTXSW
  sched: Fix ancient race in do_exit()
  sched/nohz: Fix nohz cpu idle load balancing state with cpu hotplug
  sched/s390: Fix compile error in sched/core.c
  sched: Fix rq->nr_uninterruptible update race

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/reboot: Remove VersaLogic Menlow reboot quirk
  x86/reboot: Skip DMI checks if reboot set by user
  x86: Properly parenthesize cmpxchg() macro arguments
2012-02-02 11:11:13 -08:00
Linus Torvalds
ce106ad310 Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security
* 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  lib: Fix 32-bit sparc udiv_qrnnd() definition in mpilib's longlong.h
  lib: Fix multiple definitions of clz_tab
  lib/digsig: checks for NULL return value
  lib/mpi: added missing NULL check
  lib/mpi: added comment on divide by 0 case
  lib/mpi: check for possible zero length
  lib/digsig: pkcs_1_v1_5_decode_emsa cleanup
  lib/digsig: additional sanity checks against badly formated key payload
  lib/mpi: removed unused functions
  lib/mpi: checks for zero divisor length
  lib/mpi: return error code on dividing by zero
  lib/mpi: replaced MPI_NULL with normal NULL
  lib/mpi: added missing NULL check
2012-02-01 16:00:38 -08:00
Kuninori Morimoto
504b61630a usb: ch9.h: usb_endpoint_maxp() uses __le16_to_cpu()
The usb/ch9.h will be installed to /usr/include/linux,
and be used from user space.
But le16_to_cpu() is only defined for kernel code.
Without this patch, user space compile will be broken.
Special thanks to Stefan Becker

Reported-by: Stefan Becker <chemobejk@gmail.com>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2012-02-01 15:56:19 -08:00
Artem Bityutskiy
7d73101921 mtd: fix merge conflict resolution breakage
This patch fixes merge conflict resolution breakage introduced by merge
d3712b9dfc ("Merge tag 'for-linus' of git://github.com/prasad-joshi/logfs_upstream").

The commit changed 'mtd_can_have_bb()' function and made it always
return zero, which is incorrect.  Instead, we need it to return whether
the underlying flash device can have bad eraseblocks or not.  UBI needs
this information because it affects how it handles the underlying flash.
E.g., if the underlying flash is NOR, it cannot have bad blocks and any
write or erase error is fatal, and all we can do is to switch to R/O
mode.  We do not need to reserve a pool of good eraseblocks for bad
eraseblocks handling, and so on.

This patch also removes 'mtd_can_have_bb()' invocations from Logfs to
ensure correct Logfs behavior.

I've tested that with this patch UBI works on top of NOR and NAND
flashes emulated by mtdram and nandsim correspondingly.

This patch is based on patch from Linus Torvalds.

Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Acked-by: Jörn Engel <joern@logfs.org>
Acked-by: Prasad Joshi <prasadjoshi.linux@gmail.com>
Acked-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-02-01 11:10:24 -08:00
Heiko Stübner
b18db3d912 Input: gpio_keys - fix struct device declared inside parameter list
A struct device parameter is used in the enable and disable callbacks to
distinguish between different gpio_keys devices.

Platforms that don't use these callbacks may not include struct device
at all, as seen on arch/arm/mach-s3c2410/mach-n30.c

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
2012-02-01 09:13:11 -08:00
Guennadi Liakhovetski
e9c8d7a03e dma: sh_dma: not all SH DMAC implementations support MEMCPY
Add a flag to allow platforms to specify, whether a DMAC instance supports
the MEMCPY operation. To avoid regressions, preserve the current default.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>
2012-02-01 22:23:53 +05:30
Dmitry Kasatkin
3cccd1543a lib/mpi: replaced MPI_NULL with normal NULL
MPI_NULL is replaced with normal NULL.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Reviewed-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: James Morris <jmorris@namei.org>
2012-02-02 00:23:14 +11:00
Linus Torvalds
d3712b9dfc Merge tag 'for-linus' of git://github.com/prasad-joshi/logfs_upstream
There are few important bug fixes for LogFS

* tag 'for-linus' of git://github.com/prasad-joshi/logfs_upstream:
  Logfs: Allow NULL block_isbad() methods
  logfs: Grow inode in delete path
  logfs: Free areas before calling generic_shutdown_super()
  logfs: remove useless BUG_ON
  MAINTAINERS: Add Prasad Joshi in LogFS maintiners
  logfs: Propagate page parameter to __logfs_write_inode
  logfs: set superblock shutdown flag after generic sb shutdown
  logfs: take write mutex lock during fsync and sync
  logfs: Prevent memory corruption
  logfs: update page reference count for pined pages

Fix up conflict in fs/logfs/dev_mtd.c due to semantic change in what
"mtd->block_isbad" means in commit f2933e86ad: "Logfs: Allow NULL
block_isbad() methods" clashing with the abstraction changes in the
commits 7086c19d07: "mtd: introduce mtd_block_isbad interface" and
d58b27ed58: "logfs: do not use 'mtd->block_isbad' directly".

This resolution takes the semantics from commit f2933e86ad, and just
makes mtd_block_isbad() return zero (false) if the 'block_isbad'
function is NULL.  But that also means that now "mtd_can_have_bb()"
always returns 0.

Now, "mtd_block_markbad()" will obviously return an error if the
low-level driver doesn't support bad blocks, so this is somewhat
non-symmetric, but it actually makes sense if a NULL "block_isbad"
function is considered to mean "I assume that all my blocks are always
good".
2012-01-31 09:23:59 -08:00
Linus Torvalds
6bc2b95ee6 Merge tag 'usb-3.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb
Here are a bunch of USB patches for 3.3-rc1.

Nothing major, largest thing here is the removal of some drivers that
did not work at all.  Other than that, the normal collection of bugfixes
and new device ids.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

* tag 'usb-3.3-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (52 commits)
  uwb & wusb: fix kconfig error
  USB: Realtek cr: fix autopm scheduling while atomic
  USB: ftdi_sio: Add more identifiers
  xHCI: Cleanup isoc transfer ring when TD length mismatch found
  usb: musb: omap2430: minor cleanups.
  qcaux: add more Pantech UML190 and UML290 ports
  Revert "drivers: usb: Fix dependency for USB_HWA_HCD"
  usb: mv-otg - Fix build if CONFIG_USB is not set
  USB: cdc-wdm: Avoid hanging on interface with no USB_CDC_DMM_TYPE
  usb: add support for STA2X11 host driver
  drivers: usb: Fix dependency for USB_HWA_HCD
  kernel-doc: fix new warning in usb.h
  USB: OHCI: fix new compiler warnings
  usb: serial: kobil_sct: fix compile warning:
  drivers/usb/host/ehci-fsl.c: add missing iounmap
  USB: cdc-wdm: better allocate a buffer that is at least as big as we tell the USB core
  USB: cdc-wdm: call wake_up_all to allow driver to shutdown on device removal
  USB: cdc-wdm: use two mutexes to allow simultaneous read and write
  USB: cdc-wdm: updating desc->length must be protected by spin_lock
  USB: usbsevseg: fix max length
  ...
2012-01-30 11:38:28 -08:00
Artem Bityutskiy
1a30871fe6 mtd: fix MTD suspend
Commits 3fe4bae884 and
079c985e7a broke MTD suspend in 2 ways:

1. When the '->suspend' method is not present, we return -EOPNOTSUPP, but
   the callers of 'mtd_suspend()' expects 0 instead.
2. Checking of the 'mtd' parameter against NULL has been incorrectly removed
   in 'mtd_cls_suspend()'.

This patch fixes the breakages. This has been found, analyzed, reported
and tested by Rafael J. Wysocki <rjw@sisk.pl>.

Note, this patch is not needed in the stable tree because it causes a
regression introduced during the v3.3 merge window.

Reported-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Rafael J. Wysocki <rjw@sisk.pl>
Tested-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
2012-01-30 14:23:07 +00:00
Rafael J. Wysocki
181e9bdef3 PM / Hibernate: Fix s2disk regression related to freezing workqueues
Commit 2aede851dd

  PM / Hibernate: Freeze kernel threads after preallocating memory

introduced a mechanism by which kernel threads were frozen after
the preallocation of hibernate image memory to avoid problems with
frozen kernel threads not responding to memory freeing requests.
However, it overlooked the s2disk code path in which the
SNAPSHOT_CREATE_IMAGE ioctl was run directly after SNAPSHOT_FREE,
which caused freeze_workqueues_begin() to BUG(), because it saw
that worqueues had been already frozen.

Although in principle this issue might be addressed by removing
the relevant BUG_ON() from freeze_workqueues_begin(), that would
reintroduce the very problem that commit 2aede851dd
attempted to avoid into that particular code path.  For this reason,
to fix the issue at hand, introduce thaw_kernel_threads() and make
the SNAPSHOT_FREE ioctl execute it.

Special thanks to Srivatsa S. Bhat for detailed analysis of the
problem.

Reported-and-tested-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: stable@kernel.org
2012-01-29 20:35:52 +01:00
Linus Torvalds
0a96265754 Merge tag 'driver-core-3.3-rc1-bugfixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Here are some patches for the 3.3-rc1 tree.

It contains the removal of the sysdev code, now that all users of it are
gone, as well as some sysfs bugfixes that have been reported by users.
There are also some documentation updates here as well.

* tag 'driver-core-3.3-rc1-bugfixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  sysfs: Complain bitterly about attempts to remove files from nonexistent directories.
  stable: update documentation to ask for kernel version
  base/core.c:fix typo in comment in function device_add
  Documentation: devres: add allocation functions to list of supported calls
  Documentation update for the driver model core
  kernel-doc: fix new warnings in driver-core
  kernel-doc: fix new warnings in debugfs
  kernel-doc: fix new warnings in device.h
  driver core: remove drivers/base/sys.c and include/linux/sysdev.h
2012-01-28 18:20:48 -08:00
Linus Torvalds
deb9b4ce97 Merge branch 'fixes' of git://git.linaro.org/people/rmk/linux-arm
* 'fixes' of git://git.linaro.org/people/rmk/linux-arm: (31 commits)
  ARM: 7304/1: ioremap: fix boundary check when reusing static mapping
  ARM: 7301/1: Rename the T() macro to TUSER() to avoid namespace conflicts
  ARM: 7299/1: ftrace: clear zero bit in reported IPs for Thumb-2
  ARM: 7298/1: realview: fix mapping of MPCore private memory region
  PCMCIA: fix sa1111 oops on remove
  ARM: 7288/1: mach-sa1100: add missing module_init() call
  ARM: 7297/1: smp_twd: make sure timer is stopped before registering it
  ARM: 7296/1: proc-v7.S: remove HARVARD_CACHE preprocessor guards
  ARM: 7295/1: cortex-a7: move proc_info out of !CONFIG_ARM_LPAE block
  ARM: 7293/1: logical_cpu_map: decouple CPU mapping from SMP
  ARM: 7291/1: cache: assume 64-byte L1 cachelines for ARMv7 CPUs
  ARM: 7290/1: vmlinux.lds.S: align the exception fixup table to a 4-byte boundary
  ARM: 7289/1: vmlinux.lds.S: do not hardcode cacheline size as 32 bytes
  MFD: ucb1x00-ts: fix resume failure
  MFD: ucb1x00-core: fix gpiolib direction_output handling
  MFD: ucb1x00-core: fix missing restore of io output data on resume
  MFD: mcp-core: fix mcp_priv() to be more type safe
  MFD: mcp-core: fix complaints from the genirq layer
  Revert "ARM: sa11x0: Implement autoloading of codec and codec pdata for mcp bus."
  Revert "ARM: sa1100: Refactor mcp-sa11x0 to use platform resources."
  ...

Fix up conflict due to arch/arm/mach-mx5/Kconfig having been merged into
mach-imx5 (commit 784a90c0a7: "ARM i.MX: Merge i.MX5 support into
mach-imx"), but the ARM_L1_CACHE_SHIFT_6 entry was moved to be driven by
the CPU_V7 logic from it in the old location in rmk's branch (commit
a092f2b153: "ARM: 7291/1: cache: assume 64-byte L1 cachelines for
ARMv7 CPUs").
2012-01-28 13:27:10 -08:00
Stephane Eranian
e050e3f0a7 perf: Fix broken interrupt rate throttling
This patch fixes the sampling interrupt throttling mechanism.

It was broken in v3.2. Events were not being unthrottled. The
unthrottling mechanism required that events be checked at each
timer tick.

This patch solves this problem and also separates:

  - unthrottling
  - multiplexing
  - frequency-mode period adjustments

Not all of them need to be executed at each timer tick.

This third version of the patch is based on my original patch +
PeterZ proposal (https://lkml.org/lkml/2012/1/7/87).

At each timer tick, for each context:

  - if the current CPU has throttled events, we unthrottle events

  - if context has frequency-based events, we adjust sampling periods

  - if we have reached the jiffies interval, we multiplex (rotate)

We decoupled rotation (multiplexing) from frequency-mode sampling
period adjustments.  They should not necessarily happen at the same
rate. Multiplexing is subject to jiffies_interval (currently at 1
but could be higher once the tunable is exposed via sysfs).

We have grouped frequency-mode adjustment and unthrottling into the
same routine to minimize code duplication. When throttled while in
frequency mode, we scan the events only once.

We have fixed the threshold enforcement code in __perf_event_overflow().
There was a bug whereby it would allow more than the authorized rate
because an increment of hwc->interrupts was not executed at the right
place.

The patch was tested with low sampling limit (2000) and fixed periods,
frequency mode, overcommitted PMU.

On a 2.1GHz AMD CPU:

 $ cat /proc/sys/kernel/perf_event_max_sample_rate
 2000

We set a rate of 3000 samples/sec (2.1GHz/3000 = 700000):

 $ perf record -e cycles,cycles -c 700000  noploop 10
 $ perf report -D | tail -21

 Aggregated stats:
           TOTAL events:      80086
            MMAP events:         88
            COMM events:          2
            EXIT events:          4
        THROTTLE events:      19996
      UNTHROTTLE events:      19996
          SAMPLE events:      40000

 cycles stats:
           TOTAL events:      40006
            MMAP events:          5
            COMM events:          1
            EXIT events:          4
        THROTTLE events:       9998
      UNTHROTTLE events:       9998
          SAMPLE events:      20000

 cycles stats:
           TOTAL events:      39996
        THROTTLE events:       9998
      UNTHROTTLE events:       9998
          SAMPLE events:      20000

For 10s, the cap is 2x2000x10 = 40000 samples.
We get exactly that: 20000 samples/event.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: <stable@kernel.org> # v3.2+
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20120126160319.GA5655@quad
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-01-27 12:06:39 +01:00