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  1. 25 Jun, 2019 19 commits
  3. 24 Jun, 2019 11 commits
    • Ian Rogers's avatar
      perf/cgroups: Don't rotate events for cgroups unnecessarily · fd7d5517
      Ian Rogers authored 
      Currently perf_rotate_context assumes that if the context's nr_events !=
nr_active a rotation is necessary for perf event multiplexing. With
cgroups, nr_events is the total count of events for all cgroups and
nr_active will not include events in a cgroup other than the current
task's. This makes rotation appear necessary for cgroups when it is not.

Add a perf_event_context flag that is set when rotation is necessary.
Clear the flag during sched_out and set it when a flexible sched_in
fails due to resources.
Signed-off-by: default avatarIan Rogers <irogers@google.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/20190601082722.44543-1-irogers@google.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      fd7d5517
    • Jiri Olsa's avatar
      perf/x86/rapl: Get quirk state from new probe framework · 637d97b5
      Jiri Olsa authored 
      Getting the apply_quirk bool from new rapl_model_match array.

And because apply_quirk was the last remaining piece of data
in rapl_cpu_match, replacing it with rapl_model_match as device
table.

The switch to new perf_msr_probe detection API is done.
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan <kan.liang@linux.intel.com>
Cc: Liang
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/20190616140358.27799-9-jolsa@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      637d97b5
    • Jiri Olsa's avatar
      perf/x86/rapl: Get attributes from new probe framework · 5fc1bd84
      Jiri Olsa authored 
      We no longer need model specific attribute arrays,
because we get all this detected in rapl_events_attrs.
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan <kan.liang@linux.intel.com>
Cc: Liang
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/20190616140358.27799-8-jolsa@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      5fc1bd84
    • Jiri Olsa's avatar
      perf/x86/rapl: Get MSR values from new probe framework · 122f1c51
      Jiri Olsa authored 
      There's no need to have special code for getting
the bit and MSR value for given event. We can
now easily get it from rapl_msrs array.

Also getting rid of RAPL_IDX_*, which is no longer
needed and replacing INTEL_RAPL* with PERF_RAPL*
enums.
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan <kan.liang@linux.intel.com>
Cc: Liang
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/20190616140358.27799-7-jolsa@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      122f1c51
    • Jiri Olsa's avatar
      perf/x86/rapl: Get rapl_cntr_mask from new probe framework · cd105aed
      Jiri Olsa authored 
      We get rapl_cntr_mask from perf_msr_probe call, as a replacement
for current intel_rapl_init_fun::cntr_mask value for each model.
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan <kan.liang@linux.intel.com>
Cc: Liang
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/20190616140358.27799-6-jolsa@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      cd105aed
    • Jiri Olsa's avatar
      perf/x86/rapl: Use new MSR detection interface · 5fb5273a
      Jiri Olsa authored 
      Using perf_msr_probe function to probe for RAPL MSRs.

Adding new rapl_model_match device table, that
gathers events info for given model, following
the MSR and cstate module design.

It will replace the current rapl_cpu_match device
table and detection code in following patches.
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan <kan.liang@linux.intel.com>
Cc: Liang
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/20190616140358.27799-5-jolsa@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      5fb5273a
    • Jiri Olsa's avatar
      perf/x86/cstate: Use new probe function · 8f2a28c5
      Jiri Olsa authored 
      Using perf_msr_probe function to probe for cstate events.

The functionality is the same, with one exception, that
perf_msr_probe checks for rdmsr to return value != 0 for
given MSR register.

Using the new attribute groups and adding the events via
pmu::attr_update.
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan <kan.liang@linux.intel.com>
Cc: Liang
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/20190616140358.27799-4-jolsa@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      8f2a28c5
    • Jiri Olsa's avatar
      perf/x86/msr: Use new probe function · dde5e720
      Jiri Olsa authored 
      Using perf_msr_probe function to probe for msr events.

The functionality is the same, with one exception, that
perf_msr_probe checks for rdmsr to return value != 0 for
given MSR register.

Using the new attribute groups and adding the events via
pmu::attr_update.
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan <kan.liang@linux.intel.com>
Cc: Liang
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/20190616140358.27799-3-jolsa@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      dde5e720
    • Jiri Olsa's avatar
      perf/x86: Add MSR probe interface · 98253a54
      Jiri Olsa authored 
      Adding perf_msr_probe function to provide interface for
checking up on MSR register and set the related attribute
group visibility.

User defines following struct for each MSR register:

  struct perf_msr {
       u64                       msr;
       struct attribute_group   *grp;
       bool                    (*test)(int idx, void *data);
       bool                      no_check;
  };

Where:
  msr      - is the MSR address
  attrs    - is attribute groups array to add if the check passed
  test     - is test function pointer
  no_check - is bool that bypass the check and adds the
              attribute without any test

The array of struct perf_msr is passed into:

  perf_msr_probe(struct perf_msr *msr, int cnt, bool zero, void *data)

Together with:
  cnt  - which is the number of struct msr array elements
  data - which is user pointer passed to the test function
  zero - allow counters that returns zero on rdmsr

The perf_msr_probe will executed test code, read the MSR and
check the value is != 0. If all these tests pass, related
attribute group is kept visible.

Also adding PMU_EVENT_GROUP macro helper to define attribute
group for single attribute. It will be used in following patches.
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan <kan.liang@linux.intel.com>
Cc: Liang
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lkml.kernel.org/r/20190616140358.27799-2-jolsa@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      98253a54
    • Ingo Molnar's avatar
      Merge branch 'x86/cpu' into perf/core, to pick up dependent patches · 9e6e87e6
      Ingo Molnar authored 
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      9e6e87e6
    • Ingo Molnar's avatar
      Merge tag 'v5.2-rc6' into perf/core, to refresh branch · b9271f0c
      Ingo Molnar authored 
      Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      b9271f0c
  5. 23 Jun, 2019 5 commits
    • Fenghua Yu's avatar
      Documentation/ABI: Document umwait control sysfs interfaces · 203dffac
      Fenghua Yu authored 
      Since two new sysfs interface files are created for umwait control, add
an ABI document entry for the files:

   /sys/devices/system/cpu/umwait_control/enable_c02
   /sys/devices/system/cpu/umwait_control/max_time

[ tglx: Made the write value instructions readable ]
Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarAshok Raj <ashok.raj@intel.com>
Cc: "Borislav Petkov" <bp@alien8.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Andy Lutomirski" <luto@kernel.org>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Link: https://lkml.kernel.org/r/1560994438-235698-6-git-send-email-fenghua.yu@intel.com
      203dffac
    • Fenghua Yu's avatar
      x86/umwait: Add sysfs interface to control umwait maximum time · bd9a0c97
      Fenghua Yu authored 
      IA32_UMWAIT_CONTROL[31:2] determines the maximum time in TSC-quanta
that processor can stay in C0.1 or C0.2. A zero value means no maximum
time.

Each instruction sets its own deadline in the instruction's implicit
input EDX:EAX value. The instruction wakes up if the time-stamp counter
reaches or exceeds the specified deadline, or the umwait maximum time
expires, or a store happens in the monitored address range in umwait.

The administrator can write an unsigned 32-bit number to
/sys/devices/system/cpu/umwait_control/max_time to change the default
value. Note that a value of zero means there is no limit. The lower two
bits of the value must be zero.

[ tglx: Simplify the write function. Massage changelog ]
Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarAshok Raj <ashok.raj@intel.com>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Cc: "Borislav Petkov" <bp@alien8.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Andy Lutomirski" <luto@kernel.org>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Link: https://lkml.kernel.org/r/1560994438-235698-5-git-send-email-fenghua.yu@intel.com
      bd9a0c97
    • Fenghua Yu's avatar
      x86/umwait: Add sysfs interface to control umwait C0.2 state · ff4b353f
      Fenghua Yu authored 
      C0.2 state in umwait and tpause instructions can be enabled or disabled
on a processor through IA32_UMWAIT_CONTROL MSR register.

By default, C0.2 is enabled and the user wait instructions results in
lower power consumption with slower wakeup time.

But in real time systems which require faster wakeup time although power
savings could be smaller, the administrator needs to disable C0.2 and all
umwait invocations from user applications use C0.1.

Create a sysfs interface which allows the administrator to control C0.2
state during run time.

Andy Lutomirski suggested to turn off local irqs before writing the MSR to
ensure the cached control value is not changed by a concurrent sysfs write
from a different CPU via IPI.

[ tglx: Simplified the update logic in the write function and got rid of
  	all the convoluted type casts. Added a shared update function and
	made the namespace consistent. Moved the sysfs create invocation.
	Massaged changelog ]
Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarAshok Raj <ashok.raj@intel.com>
Reviewed-by: default avatarTony Luck <tony.luck@intel.com>
Cc: "Borislav Petkov" <bp@alien8.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Andy Lutomirski" <luto@kernel.org>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Link: https://lkml.kernel.org/r/1560994438-235698-4-git-send-email-fenghua.yu@intel.com
      ff4b353f
    • Fenghua Yu's avatar
      x86/umwait: Initialize umwait control values · bd688c69
      Fenghua Yu authored 
      umwait or tpause allows the processor to enter a light-weight
power/performance optimized state (C0.1 state) or an improved
power/performance optimized state (C0.2 state) for a period specified by
the instruction or until the system time limit or until a store to the
monitored address range in umwait.

IA32_UMWAIT_CONTROL MSR register allows the OS to enable/disable C0.2 on
the processor and to set the maximum time the processor can reside in C0.1
or C0.2.

By default C0.2 is enabled so the user wait instructions can enter the
C0.2 state to save more power with slower wakeup time.

Andy Lutomirski proposed to set the maximum umwait time to 100000 cycles by
default. A quote from Andy:

  "What I want to avoid is the case where it works dramatically differently
   on NO_HZ_FULL systems as compared to everything else. Also, UMWAIT may
   behave a bit differently if the max timeout is hit, and I'd like that
   path to get exercised widely by making it happen even on default
   configs."

A sysfs interface to adjust the time and the C0.2 enablement is provided in
a follow up change.

[ tglx: Renamed MSR_IA32_UMWAIT_CONTROL_MAX_TIME to
  	MSR_IA32_UMWAIT_CONTROL_TIME_MASK because the constant is used as
  	mask throughout the code.
	Massaged comments and changelog ]
Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarAshok Raj <ashok.raj@intel.com>
Reviewed-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: "Borislav Petkov" <bp@alien8.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Link: https://lkml.kernel.org/r/1560994438-235698-3-git-send-email-fenghua.yu@intel.com
      bd688c69
    • Fenghua Yu's avatar
      x86/cpufeatures: Enumerate user wait instructions · 6dbbf5ec
      Fenghua Yu authored 
      umonitor, umwait, and tpause are a set of user wait instructions.

umonitor arms address monitoring hardware using an address. The
address range is determined by using CPUID.0x5. A store to
an address within the specified address range triggers the
monitoring hardware to wake up the processor waiting in umwait.

umwait instructs the processor to enter an implementation-dependent
optimized state while monitoring a range of addresses. The optimized
state may be either a light-weight power/performance optimized state
(C0.1 state) or an improved power/performance optimized state
(C0.2 state).

tpause instructs the processor to enter an implementation-dependent
optimized state C0.1 or C0.2 state and wake up when time-stamp counter
reaches specified timeout.

The three instructions may be executed at any privilege level.

The instructions provide power saving method while waiting in
user space. Additionally, they can allow a sibling hyperthread to
make faster progress while this thread is waiting. One example of an
application usage of umwait is when waiting for input data from another
application, such as a user level multi-threaded packet processing
engine.

Availability of the user wait instructions is indicated by the presence
of the CPUID feature flag WAITPKG CPUID.0x07.0x0:ECX[5].

Detailed information on the instructions and CPUID feature WAITPKG flag
can be found in the latest Intel Architecture Instruction Set Extensions
and Future Features Programming Reference and Intel 64 and IA-32
Architectures Software Developer's Manual.
Signed-off-by: default avatarFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarAshok Raj <ashok.raj@intel.com>
Reviewed-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: "Borislav Petkov" <bp@alien8.de>
Cc: "H Peter Anvin" <hpa@zytor.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Link: https://lkml.kernel.org/r/1560994438-235698-2-git-send-email-fenghua.yu@intel.com
      6dbbf5ec
  7. 22 Jun, 2019 5 commits
    • Linus Torvalds's avatar
      Linux 5.2-rc6 · 4b972a01
      Linus Torvalds authored
      4b972a01
    • Linus Torvalds's avatar
      Merge tag 'iommu-fix-v5.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu · 6698a71a
      Linus Torvalds authored 
      Pull iommu fix from Joerg Roedel:
 "Revert a commit from the previous pile of fixes which causes new
  lockdep splats. It is better to revert it for now and work on a better
  and more well tested fix"

* tag 'iommu-fix-v5.2-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  Revert "iommu/vt-d: Fix lock inversion between iommu->lock and device_domain_lock"
      6698a71a
    • Peter Xu's avatar
      Revert "iommu/vt-d: Fix lock inversion between iommu->lock and device_domain_lock" · 0aafc8ae
      Peter Xu authored 
      This reverts commit 7560cc3c.

With 5.2.0-rc5 I can easily trigger this with lockdep and iommu=pt:

    ======================================================
    WARNING: possible circular locking dependency detected
    5.2.0-rc5 #78 Not tainted
    ------------------------------------------------------
    swapper/0/1 is trying to acquire lock:
    00000000ea2b3beb (&(&iommu->lock)->rlock){+.+.}, at: domain_context_mapping_one+0xa5/0x4e0
    but task is already holding lock:
    00000000a681907b (device_domain_lock){....}, at: domain_context_mapping_one+0x8d/0x4e0
    which lock already depends on the new lock.
    the existing dependency chain (in reverse order) is:
    -> #1 (device_domain_lock){....}:
           _raw_spin_lock_irqsave+0x3c/0x50
           dmar_insert_one_dev_info+0xbb/0x510
           domain_add_dev_info+0x50/0x90
           dev_prepare_static_identity_mapping+0x30/0x68
           intel_iommu_init+0xddd/0x1422
           pci_iommu_init+0x16/0x3f
           do_one_initcall+0x5d/0x2b4
           kernel_init_freeable+0x218/0x2c1
           kernel_init+0xa/0x100
           ret_from_fork+0x3a/0x50
    -> #0 (&(&iommu->lock)->rlock){+.+.}:
           lock_acquire+0x9e/0x170
           _raw_spin_lock+0x25/0x30
           domain_context_mapping_one+0xa5/0x4e0
           pci_for_each_dma_alias+0x30/0x140
           dmar_insert_one_dev_info+0x3b2/0x510
           domain_add_dev_info+0x50/0x90
           dev_prepare_static_identity_mapping+0x30/0x68
           intel_iommu_init+0xddd/0x1422
           pci_iommu_init+0x16/0x3f
           do_one_initcall+0x5d/0x2b4
           kernel_init_freeable+0x218/0x2c1
           kernel_init+0xa/0x100
           ret_from_fork+0x3a/0x50

    other info that might help us debug this:
     Possible unsafe locking scenario:
           CPU0                    CPU1
           ----                    ----
      lock(device_domain_lock);
                                   lock(&(&iommu->lock)->rlock);
                                   lock(device_domain_lock);
      lock(&(&iommu->lock)->rlock);

     *** DEADLOCK ***
    2 locks held by swapper/0/1:
     #0: 00000000033eb13d (dmar_global_lock){++++}, at: intel_iommu_init+0x1e0/0x1422
     #1: 00000000a681907b (device_domain_lock){....}, at: domain_context_mapping_one+0x8d/0x4e0

    stack backtrace:
    CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.2.0-rc5 #78
    Hardware name: LENOVO 20KGS35G01/20KGS35G01, BIOS N23ET50W (1.25 ) 06/25/2018
    Call Trace:
     dump_stack+0x85/0xc0
     print_circular_bug.cold.57+0x15c/0x195
     __lock_acquire+0x152a/0x1710
     lock_acquire+0x9e/0x170
     ? domain_context_mapping_one+0xa5/0x4e0
     _raw_spin_lock+0x25/0x30
     ? domain_context_mapping_one+0xa5/0x4e0
     domain_context_mapping_one+0xa5/0x4e0
     ? domain_context_mapping_one+0x4e0/0x4e0
     pci_for_each_dma_alias+0x30/0x140
     dmar_insert_one_dev_info+0x3b2/0x510
     domain_add_dev_info+0x50/0x90
     dev_prepare_static_identity_mapping+0x30/0x68
     intel_iommu_init+0xddd/0x1422
     ? printk+0x58/0x6f
     ? lockdep_hardirqs_on+0xf0/0x180
     ? do_early_param+0x8e/0x8e
     ? e820__memblock_setup+0x63/0x63
     pci_iommu_init+0x16/0x3f
     do_one_initcall+0x5d/0x2b4
     ? do_early_param+0x8e/0x8e
     ? rcu_read_lock_sched_held+0x55/0x60
     ? do_early_param+0x8e/0x8e
     kernel_init_freeable+0x218/0x2c1
     ? rest_init+0x230/0x230
     kernel_init+0xa/0x100
     ret_from_fork+0x3a/0x50

domain_context_mapping_one() is taking device_domain_lock first then
iommu lock, while dmar_insert_one_dev_info() is doing the reverse.

That should be introduced by commit:

7560cc3c ("iommu/vt-d: Fix lock inversion between iommu->lock and
              device_domain_lock", 2019-05-27)

So far I still cannot figure out how the previous deadlock was
triggered (I cannot find iommu lock taken before calling of
iommu_flush_dev_iotlb()), however I'm pretty sure that that change
should be incomplete at least because it does not fix all the places
so we're still taking the locks in different orders, while reverting
that commit is very clean to me so far that we should always take
device_domain_lock first then the iommu lock.

We can continue to try to find the real culprit mentioned in
7560cc3c, but for now I think we should revert it to fix current
breakage.

CC: Joerg Roedel <joro@8bytes.org>
CC: Lu Baolu <baolu.lu@linux.intel.com>
CC: dave.jiang@intel.com
Signed-off-by: default avatarPeter Xu <peterx@redhat.com>
Tested-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
      0aafc8ae
    • Linus Torvalds's avatar
      Merge tag 'pci-v5.2-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci · b253d5f3
      Linus Torvalds authored 
      Pull PCI fix from Bjorn Helgaas:
 "If an IOMMU is present, ignore the P2PDMA whitelist we added for v5.2
  because we don't yet know how to support P2PDMA in that case (Logan
  Gunthorpe)"

* tag 'pci-v5.2-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI/P2PDMA: Ignore root complex whitelist when an IOMMU is present
      b253d5f3
    • Linus Torvalds's avatar
      Merge tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi · f4102766
      Linus Torvalds authored 
      Pull SCSI fixes from James Bottomley:
 "Three driver fixes (and one version number update): a suspend hang in
  ufs, a qla hard lock on module removal and a qedi panic during
  discovery"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: qla2xxx: Fix hardlockup in abort command during driver remove
  scsi: ufs: Avoid runtime suspend possibly being blocked forever
  scsi: qedi: update driver version to 8.37.0.20
  scsi: qedi: Check targetname while finding boot target information
      f4102766
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