skb->truesize might be big even for a small packet.
Its even bigger after commit 87fb4b7b53 (net: more accurate skb
truesize) and big MTU.
We should allow queueing at least one packet per receiver, even with a
low RCVBUF setting.
Reported-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, the *_global_[un]lock_online() routines are not at all synchronized
with CPU hotplug. Soft-lockups detected as a consequence of this race was
reported earlier at https://lkml.org/lkml/2011/8/24/185. (Thanks to Cong Meng
for finding out that the root-cause of this issue is the race condition
between br_write_[un]lock() and CPU hotplug, which results in the lock states
getting messed up).
Fixing this race by just adding {get,put}_online_cpus() at appropriate places
in *_global_[un]lock_online() is not a good option, because, then suddenly
br_write_[un]lock() would become blocking, whereas they have been kept as
non-blocking all this time, and we would want to keep them that way.
So, overall, we want to ensure 3 things:
1. br_write_lock() and br_write_unlock() must remain as non-blocking.
2. The corresponding lock and unlock of the per-cpu spinlocks must not happen
for different sets of CPUs.
3. Either prevent any new CPU online operation in between this lock-unlock, or
ensure that the newly onlined CPU does not proceed with its corresponding
per-cpu spinlock unlocked.
To achieve all this:
(a) We introduce a new spinlock that is taken by the *_global_lock_online()
routine and released by the *_global_unlock_online() routine.
(b) We register a callback for CPU hotplug notifications, and this callback
takes the same spinlock as above.
(c) We maintain a bitmap which is close to the cpu_online_mask, and once it is
initialized in the lock_init() code, all future updates to it are done in
the callback, under the above spinlock.
(d) The above bitmap is used (instead of cpu_online_mask) while locking and
unlocking the per-cpu locks.
The callback takes the spinlock upon the CPU_UP_PREPARE event. So, if the
br_write_lock-unlock sequence is in progress, the callback keeps spinning,
thus preventing the CPU online operation till the lock-unlock sequence is
complete. This takes care of requirement (3).
The bitmap that we maintain remains unmodified throughout the lock-unlock
sequence, since all updates to it are managed by the callback, which takes
the same spinlock as the one taken by the lock code and released only by the
unlock routine. Combining this with (d) above, satisfies requirement (2).
Overall, since we use a spinlock (mentioned in (a)) to prevent CPU hotplug
operations from racing with br_write_lock-unlock, requirement (1) is also
taken care of.
By the way, it is to be noted that a CPU offline operation can actually run
in parallel with our lock-unlock sequence, because our callback doesn't react
to notifications earlier than CPU_DEAD (in order to maintain our bitmap
properly). And this means, since we use our own bitmap (which is stale, on
purpose) during the lock-unlock sequence, we could end up unlocking the
per-cpu lock of an offline CPU (because we had locked it earlier, when the
CPU was online), in order to satisfy requirement (2). But this is harmless,
though it looks a bit awkward.
Debugged-by: Cong Meng <mc@linux.vnet.ibm.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
net: Add a flow_cache_flush_deferred function
ipv4: reintroduce route cache garbage collector
net: have ipconfig not wait if no dev is available
sctp: Do not account for sizeof(struct sk_buff) in estimated rwnd
asix: new device id
davinci-cpdma: fix locking issue in cpdma_chan_stop
sctp: fix incorrect overflow check on autoclose
r8169: fix Config2 MSIEnable bit setting.
llc: llc_cmsg_rcv was getting called after sk_eat_skb.
net: bpf_jit: fix an off-one bug in x86_64 cond jump target
iwlwifi: update SCD BC table for all SCD queues
Revert "Bluetooth: Revert: Fix L2CAP connection establishment"
Bluetooth: Clear RFCOMM session timer when disconnecting last channel
Bluetooth: Prevent uninitialized data access in L2CAP configuration
iwlwifi: allow to switch to HT40 if not associated
iwlwifi: tx_sync only on PAN context
mwifiex: avoid double list_del in command cancel path
ath9k: fix max phy rate at rate control init
nfc: signedness bug in __nci_request()
iwlwifi: do not set the sequence control bit is not needed
flow_cach_flush() might sleep but can be called from
atomic context via the xfrm garbage collector. So add
a flow_cache_flush_deferred() function and use this if
the xfrm garbage colector is invoked from within the
packet path.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Acked-by: Timo Teräs <timo.teras@iki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time/clocksource: Fix kernel-doc warnings
rtc: m41t80: Workaround broken alarm functionality
rtc: Expire alarms after the time is set.
* 'stable/for-linus-fixes-3.2' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
Revert "xen/pv-on-hvm kexec: add xs_reset_watches to shutdown watches from old kernel"
Commit 8ffd3208 voids the previous patches f6778aab and 810c0719 for
limiting the autoclose value. If userspace passes in -1 on 32-bit
platform, the overflow check didn't work and autoclose would be set
to 0xffffffff.
This patch defines a max_autoclose (in seconds) for limiting the value
and exposes it through sysctl, with the following intentions.
1) Avoid overflowing autoclose * HZ.
2) Keep the default autoclose bound consistent across 32- and 64-bit
platforms (INT_MAX / HZ in this patch).
3) Keep the autoclose value consistent between setsockopt() and
getsockopt() calls.
Suggested-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit ddacf5ef68.
As when booting the kernel under Amazon EC2 as an HVM guest it ends up
hanging during startup. Reverting this we loose the fix for kexec
booting to the crash kernels.
Fixes Canonical BZ #901305 (http://bugs.launchpad.net/bugs/901305)
Tested-by: Alessandro Salvatori <sandr8@gmail.com>
Reported-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Ian Campbell <Ian.Campbell@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
* git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6: (22 commits)
[SCSI] fcoe: fix fcoe in a DCB environment by adding DCB notifiers to set skb priority
[SCSI] bnx2i: Fixed kernel panic caused by unprotected task->sc->request deref
[SCSI] qla4xxx: check for failed conn setup
[SCSI] qla4xxx: a small loop fix
[SCSI] qla4xxx: fix flash/ddb support
[SCSI] zfcp: return early from slave_destroy if slave_alloc returned early
[SCSI] fcoe: Fix preempt count leak in fcoe_filter_frames()
[SCSI] qla2xxx: Update version number to 8.03.07.12-k.
[SCSI] qla2xxx: Submit all chained IOCBs for passthrough commands on request queue 0.
[SCSI] qla2xxx: Correct fc_host port_state display.
[SCSI] qla2xxx: Disable generating pause frames when firmware hang detected for ISP82xx.
[SCSI] qla2xxx: Clear mailbox busy flag during premature mailbox completion for ISP82xx.
[SCSI] qla2xxx: Encapsulate prematurely completing mailbox commands during ISP82xx firmware hang.
[SCSI] qla2xxx: Display IPE error message for ISP82xx.
[SCSI] qla2xxx: Return the correct value for a mailbox command if 82xx is in reset recovery.
[SCSI] qla2xxx: Enable Minidump by default with default capture mask 0x1f.
[SCSI] qla2xxx: Stop unconditional completion of mailbox commands issued in interrupt mode during firmware hang.
[SCSI] qla2xxx: Revert back the request queue mapping to request queue 0.
[SCSI] qla2xxx: Don't call alloc_fw_dump for ISP82XX.
[SCSI] qla2xxx: Check for SCSI status on underruns.
...
This makes the binary trace understandable by trace-cmd.
CC: Dave Chinner <david@fromorbit.com>
CC: Curt Wohlgemuth <curtw@google.com>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
* 'drm-intel-fixes' of git://people.freedesktop.org/~keithp/linux:
drm/i915/dp: Dither down to 6bpc if it makes the mode fit
drm/i915: enable semaphores on per-device defaults
drm/i915: don't set unpin_work if vblank_get fails
drm/i915: By default, enable RC6 on IVB and SNB when reasonable
iommu: Export intel_iommu_enabled to signal when iommu is in use
drm/i915/sdvo: Include LVDS panels for the IS_DIGITAL check
drm/i915: prevent division by zero when asking for chipset power
drm/i915: add PCH info to i915_capabilities
drm/i915: set the right SDVO transcoder for CPT
drm/i915: no-lvds quirk for ASUS AT5NM10T-I
drm/i915: Treat pre-gen4 backlight duty cycle value consistently
drm/i915: Hook up Ivybridge eDP
drm/i915: add multi-threaded forcewake support
In i915 driver, we do not enable either rc6 or semaphores on SNB when dmar
is enabled. The new 'intel_iommu_enabled' variable signals when the
iommu code is in operation.
Cc: Ted Phelps <phelps@gnusto.com>
Cc: Peter <pab1612@gmail.com>
Cc: Lukas Hejtmanek <xhejtman@fi.muni.cz>
Cc: Andrew Lutomirski <luto@mit.edu>
CC: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Use DCB notifiers to set the skb priority to allow packets
to be steered and tagged correctly over DCB enabled drivers
that setup traffic classes.
This allows queue_mapping() routines to be removed in these
drivers that were previously inspecting the ethertype of
every skb to mark FCoE/FIP frames.
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Exactly like roundup_pow_of_two(1), the rounddown version was buggy for
the case of a compile-time constant '1' argument. Probably because it
originated from the same code, sharing history with the roundup version
from before the bugfix (for that one, see commit 1a06a52ee1b0: "Fix
roundup_pow_of_two(1)").
However, unlike the roundup version, the fix for rounddown is to just
remove the broken special case entirely. It's simply not needed - the
generic code
1UL << ilog2(n)
does the right thing for the constant '1' argment too. The only reason
roundup needed that special case was because rounding up does so by
subtracting one from the argument (and then adding one to the result)
causing the obvious problems with "ilog2(0)".
But rounddown doesn't do any of that, since ilog2() naturally truncates
(ie "rounds down") to the right rounded down value. And without the
ilog2(0) case, there's no reason for the special case that had the wrong
value.
tl;dr: rounddown_pow_of_two(1) should be 1, not 0.
Acked-by: Dmitry Torokhov <dtor@vmware.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc:
mmc: core: Fix deadlock when the CONFIG_MMC_UNSAFE_RESUME is not defined
mmc: sdhci-s3c: Remove old and misprototyped suspend operations
mmc: tmio: fix clock gating on platforms with a .set_pwr() method
mmc: sh_mmcif: fix clock gating on platforms with a .down_pwr() method
mmc: core: Fix typo at mmc_card_sleep
mmc: core: Fix power_off_notify during suspend
mmc: core: Fix setting power notify state variable for non-eMMC
mmc: core: Add quirk for long data read time
mmc: Add module.h include to sdhci-cns3xxx.c
mmc: mxcmmc: fix falling back to PIO
mmc: omap_hsmmc: DMA unmap only once in case of MMC error
On 64-bit platforms assigning a pointer to a 32-bit variable causes a
compiler warning and cannot actually work. Soc-camera currently doesn't
support any 64-bit systems, but such platforms can be added in the
and in any case compiler warnings should be avoided.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Adds a quirk that sets the data read timeout to a fixed value instead
of relying on the information in the CSD. The timeout value chosen
is 300ms since that has proven enough for the problematic cards found,
but could be increased if other cards require this.
This patch also enables this quirk for certain Micron cards known to
have this problem.
Signed-off-by: Stefan Nilsson XK <stefan.xk.nilsson@stericsson.com>
Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Cc: <stable@kernel.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile:
arch/tile: use new generic {enable,disable}_percpu_irq() routines
drivers/net/ethernet/tile: use skb_frag_page() API
asm-generic/unistd.h: support new process_vm_{readv,write} syscalls
arch/tile: fix double-free bug in homecache_free_pages()
arch/tile: add a few #includes and an EXPORT to catch up with kernel changes.
Use atomic-long operations instead of looping around cmpxchg().
[akpm@linux-foundation.org: massage atomic.h inclusions]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* '3.2-rc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (25 commits)
iscsi-target: Fix hex2bin warn_unused compile message
target: Don't return an error if disabling unsupported features
target/rd: fix or rewrite the copy routine
target/rd: simplify the page/offset computation
target: remove the unused se_dev_list
target/file: walk properly over sg list
target: remove unused struct fields
target: Fix page length in emulated INQUIRY VPD page 86h
target: Handle 0 correctly in transport_get_sectors_6()
target: Don't return an error status for 0-length READ and WRITE
iscsi-target: Use kmemdup rather than duplicating its implementation
iscsi-target: Add missing F_BIT for iscsi_tm_rsp
iscsi-target: Fix residual count hanlding + remove iscsi_cmd->residual_count
target: Reject SCSI data overflow for fabrics using transport_generic_map_mem_to_cmd
target: remove the unused t_task_pt_sgl and t_task_pt_sgl_num se_cmd fields
target: remove the t_tasks_bidi se_cmd field
target: remove the t_tasks_fua se_cmd field
target: remove the se_ordered_node se_cmd field
target: remove the se_obj_ptr and se_orig_obj_ptr se_cmd fields
target: Drop config_item_name usage in fabric TFO->free_wwn()
...
__d_path() API is asking for trouble and in case of apparmor d_namespace_path()
getting just that. The root cause is that when __d_path() misses the root
it had been told to look for, it stores the location of the most remote ancestor
in *root. Without grabbing references. Sure, at the moment of call it had
been pinned down by what we have in *path. And if we raced with umount -l, we
could have very well stopped at vfsmount/dentry that got freed as soon as
prepend_path() dropped vfsmount_lock.
It is safe to compare these pointers with pre-existing (and known to be still
alive) vfsmount and dentry, as long as all we are asking is "is it the same
address?". Dereferencing is not safe and apparmor ended up stepping into
that. d_namespace_path() really wants to examine the place where we stopped,
even if it's not connected to our namespace. As the result, it looked
at ->d_sb->s_magic of a dentry that might've been already freed by that point.
All other callers had been careful enough to avoid that, but it's really
a bad interface - it invites that kind of trouble.
The fix is fairly straightforward, even though it's bigger than I'd like:
* prepend_path() root argument becomes const.
* __d_path() is never called with NULL/NULL root. It was a kludge
to start with. Instead, we have an explicit function - d_absolute_root().
Same as __d_path(), except that it doesn't get root passed and stops where
it stops. apparmor and tomoyo are using it.
* __d_path() returns NULL on path outside of root. The main
caller is show_mountinfo() and that's precisely what we pass root for - to
skip those outside chroot jail. Those who don't want that can (and do)
use d_path().
* __d_path() root argument becomes const. Everyone agrees, I hope.
* apparmor does *NOT* try to use __d_path() or any of its variants
when it sees that path->mnt is an internal vfsmount. In that case it's
definitely not mounted anywhere and dentry_path() is exactly what we want
there. Handling of sysctl()-triggered weirdness is moved to that place.
* if apparmor is asked to do pathname relative to chroot jail
and __d_path() tells it we it's not in that jail, the sucker just calls
d_absolute_path() instead. That's the other remaining caller of __d_path(),
BTW.
* seq_path_root() does _NOT_ return -ENAMETOOLONG (it's stupid anyway -
the normal seq_file logics will take care of growing the buffer and redoing
the call of ->show() just fine). However, if it gets path not reachable
from root, it returns SEQ_SKIP. The only caller adjusted (i.e. stopped
ignoring the return value as it used to do).
Reviewed-by: John Johansen <john.johansen@canonical.com>
ACKed-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
ftrace: Fix hash record accounting bug
perf: Fix parsing of __print_flags() in TP_printk()
jump_label: jump_label_inc may return before the code is patched
ftrace: Remove force undef config value left for testing
tracing: Restore system filter behavior
tracing: fix event_subsystem ref counting
Some are never used, some are set but never read, dev_hoq_count is
incremented and decremented, but never read.
Signed-off-by: Joern Engel <joern@logfs.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
We never walk ordered_cmd_list in the se_device, so remove all code related
to supporting it.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
We already have a perfectly valid se_device pointer in the command, so
remove the mostly useless duplicates.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Convert to unsigned bit fields for active I/O shutdown fields.
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This patch removes legacy usage of PYX_TRANSPORT_* return codes in a number
of locations and addresses cases where transport_generic_request_failure()
was returning the incorrect sense upon CHECK_CONDITION status after the
v3.1 converson to use errno return codes.
This includes the conversion of transport_generic_request_failure() to
process cmd->scsi_sense_reason and handle extra TCM_RESERVATION_CONFLICT
before calling transport_send_check_condition_and_sense() to queue up
response status. It also drops PYX_TRANSPORT_OUT_OF_MEMORY_RESOURCES legacy
usgae, and returns TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE w/ a response
for these cases.
transport_generic_allocate_tasks(), transport_generic_new_cmd(), backend
SCF_SCSI_DATA_SG_IO_CDB ->do_task(), and emulated ->execute_task() have
all been updated to set se_cmd->scsi_sense_reason and return errno codes
universally upon failure. This includes cmd->scsi_sense_reason assignment
in target_core_alua.c, target_core_pr.c and target_core_cdb.c emulation code.
Finally it updates fabric modules to remove the legacy usage, and for
TFO->new_cmd_map() callers forwards return values outside of fabric code.
iscsi-target has also been updated to remove a handful of special cases
related to the cleanup and signaling QUEUE_FULL handling w/ ft_write_pending()
(v2: Drop extra SCF_SCSI_CDB_EXCEPTION check during failure from
transport_generic_new_cmd, and re-add missing task->task_error_status
assignment in transport_complete_task)
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
intr_remapping: Fix section mismatch in ir_dev_scope_init()
intel-iommu: Fix section mismatch in dmar_parse_rmrr_atsr_dev()
x86, amd: Fix up numa_node information for AMD CPU family 15h model 0-0fh northbridge functions
x86, AMD: Correct align_va_addr documentation
x86/rtc, mrst: Don't register a platform RTC device for for Intel MID platforms
x86/mrst: Battery fixes
x86/paravirt: PTE updates in k(un)map_atomic need to be synchronous, regardless of lazy_mmu mode
x86: Fix "Acer Aspire 1" reboot hang
x86/mtrr: Resolve inconsistency with Intel processor manual
x86: Document rdmsr_safe restrictions
x86, microcode: Fix the failure path of microcode update driver init code
Add TAINT_FIRMWARE_WORKAROUND on MTRR fixup
x86/mpparse: Account for bus types other than ISA and PCI
x86, mrst: Change the pmic_gpio device type to IPC
mrst: Added some platform data for the SFI translations
x86,mrst: Power control commands update
x86/reboot: Blacklist Dell OptiPlex 990 known to require PCI reboot
x86, UV: Fix UV2 hub part number
x86: Add user_mode_vm check in stack_overflow_check
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Fix loss of notification with multi-event
perf, x86: Force IBS LVT offset assignment for family 10h
perf, x86: Disable PEBS on SandyBridge chips
trace_events_filter: Use rcu_assign_pointer() when setting ftrace_event_call->filter
perf session: Fix crash with invalid CPU list
perf python: Fix undefined symbol problem
perf/x86: Enable raw event access to Intel offcore events
perf: Don't use -ENOSPC for out of PMU resources
perf: Do not set task_ctx pointer in cpuctx if there are no events in the context
perf/x86: Fix PEBS instruction unwind
oprofile, x86: Fix crash when unloading module (nmi timer mode)
oprofile: Fix crash when unloading module (hr timer mode)
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched, x86: Avoid unnecessary overflow in sched_clock
sched: Fix buglet in return_cfs_rq_runtime()
sched: Avoid SMT siblings in select_idle_sibling() if possible
sched: Set the command name of the idle tasks in SMP kernels
sched, rt: Provide means of disabling cross-cpu bandwidth sharing
sched: Document wait_for_completion_*() return values
sched_fair: Fix a typo in the comment describing update_sd_lb_stats
sched: Add a comment to effective_load() since it's a pain
Though not all events have field 'prev_pid', it was allowed to do this:
# echo 'prev_pid == 100' > events/sched/filter
but commit 75b8e98263 (tracing/filter: Swap
entire filter of events) broke it without any reason.
Link: http://lkml.kernel.org/r/4EAF46CF.8040408@cn.fujitsu.com
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
I've received complaints that the numa_node attribute for family
15h model 00-0fh (e.g. Interlagos) northbridge functions shows
-1 instead of the proper node ID.
Correct this with attached quirks (similar to quirks for other
AMD CPU families used in multi-socket systems).
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Cc: Frank Arnold <frank.arnold@amd.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
Link: http://lkml.kernel.org/r/20111202072143.GA31916@alberich.amd.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When you do:
$ perf record -e cycles,cycles,cycles noploop 10
You expect about 10,000 samples for each event, i.e., 10s at
1000samples/sec. However, this is not what's happening. You
get much fewer samples, maybe 3700 samples/event:
$ perf report -D | tail -15
Aggregated stats:
TOTAL events: 10998
MMAP events: 66
COMM events: 2
SAMPLE events: 10930
cycles stats:
TOTAL events: 3644
SAMPLE events: 3644
cycles stats:
TOTAL events: 3642
SAMPLE events: 3642
cycles stats:
TOTAL events: 3644
SAMPLE events: 3644
On a Intel Nehalem or even AMD64, there are 4 counters capable
of measuring cycles, so there is plenty of space to measure those
events without multiplexing (even with the NMI watchdog active).
And even with multiplexing, we'd expect roughly the same number
of samples per event.
The root of the problem was that when the event that caused the buffer
to become full was not the first event passed on the cmdline, the user
notification would get lost. The notification was sent to the file
descriptor of the overflowed event but the perf tool was not polling
on it. The perf tool aggregates all samples into a single buffer,
i.e., the buffer of the first event. Consequently, it assumes
notifications for any event will come via that descriptor.
The seemingly straight forward solution of moving the waitq into the
ringbuffer object doesn't work because of life-time issues. One could
perf_event_set_output() on a fd that you're also blocking on and cause
the old rb object to be freed while its waitq would still be
referenced by the blocked thread -> FAIL.
Therefore link all events to the ringbuffer and broadcast the wakeup
from the ringbuffer object to all possible events that could be waited
upon. This is rather ugly, and we're open to better solutions but it
works for now.
Reported-by: Stephane Eranian <eranian@google.com>
Finished-by: Stephane Eranian <eranian@google.com>
Reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20111126014731.GA7030@quad
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Also prototype the "compat" functions so they can be referenced
from C code.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
* 'drm-fixes' of git://people.freedesktop.org/~airlied/linux:
vmwgfx: integer overflow in vmw_kms_update_layout_ioctl()
drm/radeon/kms: fix 2D tiling CS support on EG/CM
drm/radeon/kms: fix scanout of 2D tiled buffers on EG/CM
drm: Fix lack of CRTC disable for drm_crtc_helper_set_config(.fb=NULL)
drm/radeon/kms: add some new pci ids
drm/radeon/kms: Skip ACPI call to ATIF when possible
drm/radeon/kms: Hide debugging message
drm/radeon/kms: add some loop timeouts in pageflip code
drm/nv50/disp: silence compiler warning
drm/nouveau: fix oopses caused by clear being called on unpopulated ttms
drm/nouveau: Keep RAMIN heap within the channel.
drm/nvd0/disp: fix sor dpms typo, preventing dpms on in some situations
drm/nvc0/gr: fix TP init for transform feedback offset queries
drm/nouveau: add dumb ioctl support
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
ALSA: hda - Fix S3/S4 problem on machines with VREF-pin mute-LED
ALSA: hda_intel - revert a quirk that affect VIA chipsets
ALSA: hda - Avoid touching mute-VREF pin for IDT codecs
firmware: Sigma: Fix endianess issues
firmware: Sigma: Skip header during CRC generation
firmware: Sigma: Prevent out of bounds memory access
ALSA: usb-audio - Support for Roland GAIA SH-01 Synthesizer
ASoC: Supply dcs_codes for newer WM1811 revisions
ASoC: Error out if we can't generate a LRCLK at all for WM8994
ASoC: Correct name of Speyside Main Speaker widget
ASoC: skip resume of soc-audio devices without codecs
ASoC: cs42l51: Fix off-by-one for reg_cache_size
ASoC: drop support for PlayPaq with WM8510
ASoC: mpc8610: tell the CS4270 codec that it's the master
ASoC: cs4720: use snd_soc_cache_sync()
ASoC: SAMSUNG: Fix build error
ASoC: max9877: Update register if either val or val2 is changed
ASoC: Fix wrong define for AD1836_ADC_WORD_OFFSET
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (73 commits)
netfilter: Remove ADVANCED dependency from NF_CONNTRACK_NETBIOS_NS
ipv4: flush route cache after change accept_local
sch_red: fix red_change
Revert "udp: remove redundant variable"
bridge: master device stuck in no-carrier state forever when in user-stp mode
ipv4: Perform peer validation on cached route lookup.
net/core: fix rollback handler in register_netdevice_notifier
sch_red: fix red_calc_qavg_from_idle_time
bonding: only use primary address for ARP
ipv4: fix lockdep splat in rt_cache_seq_show
sch_teql: fix lockdep splat
net: fec: Select the FEC driver by default for i.MX SoCs
isdn: avoid copying too long drvid
isdn: make sure strings are null terminated
netlabel: Fix build problems when IPv6 is not enabled
sctp: better integer overflow check in sctp_auth_create_key()
sctp: integer overflow in sctp_auth_create_key()
ipv6: Set mcast_hops to IPV6_DEFAULT_MCASTHOPS when -1 was given.
net: Fix corruption in /proc/*/net/dev_mcast
mac80211: fix race between the AGG SM and the Tx data path
...
Linus Torvalds