Julia Lawall [Sat, 14 Jul 2012 16:43:08 +0000 (18:43 +0200)]
arch/x86/kernel/kdebugfs.c: Ensure a consistent return value in error case
Typically, the return value desired for the failure of a
function with an integer return value is a negative integer. In
these cases, the return value is sometimes a negative integer
and sometimes 0, due to a subsequent initialization of the
return variable within the loop.
A simplified version of the semantic match that finds this
problem is: (http://coccinelle.lip6.fr/)
ret = -C
... when != ret = e3
when any
if@p (...) S
... when any
if (\(ret != 0\|ret < 0\|ret > 0\) || ...) { ... return ...; }
... when != ret = e3
when any
*if@p (...)
{
... when != ret = e4
return ret;
}
//</smpl>
Tony Luck [Thu, 19 Jul 2012 18:28:46 +0000 (11:28 -0700)]
x86/mce: Add quirk for instruction recovery on Sandy Bridge processors
Sandy Bridge processors follow the SDM (Vol 3B, Table 15-20) and
set both the RIPV and EIPV bits in the MCG_STATUS register to
zero for machine checks during instruction fetch. This is more
than a little counter-intuitive and means that Linux cannot
recover from these errors. Rather than insert special case code
at several places in mce.c and mce-severity.c, we pretend the
EIPV bit was set for just this case early in processing the
machine check.
x86/ioapic: Fix NULL pointer dereference on CPU hotplug after disabling irqs
In the current kernel, percpu variable `vector_irq' is not always
cleared when a CPU is offlined. If the CPU that has the disabled
irqs in vector_irq is hotplugged again, __setup_vector_irq()
hits invalid irq vector and may crash.
To fix this problem, this patch clears vector_irq in
__fixup_irqs() when the CPU is offlined.
This also reverts commit f6175f5bfb4c, which partially fixes
this bug by clearing vector in __clear_irq_vector(). But in
environments with IOMMU IRQ remapper, it could fail because
cfg->domain doesn't contain offlined CPUs. With this patch, the
fix in __clear_irq_vector() can be reverted because every
vector_irq is already cleared in __fixup_irqs() on offlined CPUs.
perf/x86: Fix LLC-* and node-* events on Intel SandyBridge
LLC-* and node-* events require using the OFFCORE_RESPONSE events
on SandyBridge, but the hw_cache_extra_regs is left uninitialized.
This patch adds the missing extra register configure table for
SandyBridge.
The uncore subsystem in Nehalem-EX consists of 7 components
(U-Box, C-Box, B-Box, S-Box, R-Box, M-Box and W-Box). This
patch is large because the way to program these boxes is
diverse.
Signed-off-by: Yan, Zheng <zheng.z.yan@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4FF534F1.3030307@intel.com
[ Improved the code. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Andrew Vagin [Thu, 12 Jul 2012 10:14:29 +0000 (14:14 +0400)]
sched: Deliver sched_switch events to the current task
Otherwise they can't be filtered for a defined task:
perf record -e sched:sched_switch ./foo
This command doesn't report any events without this patch.
I think it isn't a security concern if someone knows who will
be executed next - this can already be observed by polling /proc
state. By default perf is disabled for non-root users in any case.
I need these events for profiling sleep times. sched_switch is used for
getting callchains and sched_stat_* is used for getting time periods.
These events are combined in user space, then it can be analyzed by
perf tools.
Namhyung Kim [Sat, 7 Jul 2012 07:49:02 +0000 (16:49 +0900)]
sched: Use task_rq_unlock() in __sched_setscheduler()
It seems there's no specific reason to open-code it. I guess
commit 0122ec5b02f76 ("sched: Add p->pi_lock to task_rq_lock()")
simply missed it. Let's be consistent with others.
perf annotate: Prevent overflow in size calculation
A large enough symbol size causes an overflow in the size parameter to
the histogram allocation, leading to a segfault in
symbol__inc_addr_samples later on when this histogram is accessed.
In the case of being called via perf-report, this returns back and
gracefully ignores the sample, eventually ignoring the chained return
value of perf_session_deliver_event in flush_sample_queue.
Signed-off-by: Cody Schafer <cody@linux.vnet.ibm.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1342753525-4521-1-git-send-email-cody@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Alan Cox [Wed, 25 Jul 2012 15:28:19 +0000 (16:28 +0100)]
x86, nops: Missing break resulting in incorrect selection on Intel
The Intel case falls through into the generic case which then changes
the values. For cases like the P6 it doesn't do the right thing so
this seems to be a screwup.
Cross compiling perf requires setting ARCH and CROSS_COMPILE variables,
but libtraceevent couldn't detect the changes so it ends up believing no
recompiling is required. Thus the linker failed like:
LINK perf
../lib/traceevent//libtraceevent.a: member ../lib/traceevent//libtraceevent.a(event-parse.o) in archive is not an object
collect2: ld returned 1 exit status
make: *** [perf] Error 1
This patch fixes this by adding TRACEEVENT-CFLAGS file like
PERF-CFLAGS to track those changes.
Signed-off-by: Namhyung Kim <namhyung@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1341559297-25725-2-git-send-email-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Bison 2.6 started to generate parse_events_parse() declaration in header. In
this case we have redundant redeclaration:
util/parse-events.c:29:5: error: redundant redeclaration of ‘parse_events_parse’ [-Werror=redundant-decls]
In file included from util/parse-events.c:14:0:
util/parse-events-bison.h:99:5: note: previous declaration of ‘parse_events_parse’ was here
cc1: all warnings being treated as errors
Let's disable -Wredundant-decls for util/parse-events.c since it includes
header we can't control.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Ingo Molnar <mingo@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120723210407.GA25186@shutemov.name Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf tools: use XSI-complaint version of strerror_r() instead of GNU-specific
Perf uses GNU-specific version of strerror_r(). The GNU-specific strerror_r()
returns a pointer to a string containing the error message. This may be either
a pointer to a string that the function stores in buf, or a pointer to some
(immutable) static string (in which case buf is unused).
In glibc-2.16 GNU version was marked with attribute warn_unused_result. It
triggers few warnings in perf:
util/target.c: In function ‘perf_target__strerror’:
util/target.c:114:13: error: ignoring return value of ‘strerror_r’, declared with attribute warn_unused_result [-Werror=unused-result]
ui/browsers/hists.c: In function ‘hist_browser__dump’:
ui/browsers/hists.c:981:13: error: ignoring return value of ‘strerror_r’, declared with attribute warn_unused_result [-Werror=unused-result]
They are bugs.
Let's fix strerror_r() usage.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: Ulrich Drepper <drepper@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ulrich Drepper <drepper@gmail.com> Link: http://lkml.kernel.org/r/20120723210654.GA25248@shutemov.name
[ committer note: s/assert/BUG_ON/g ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf tools: Make the breakpoint events sample period default to 1
There have one problem about hw_breakpoint perf event, as watched, the
events reported to userspace is not correctly, sometime one trigger
bp_event report several events, sometime bp_event cannot go through to
user.
The root cause is attr->freq is 1 passed to kernel defaultly in bp
events, this make kernel calculate event period not as expect, make
sample period to 1 will change attr->freq to 0, to fix this problem.
This patch is similar with commit f92128 about tracepoint events:
perf: Make the trace events sample period default to 1
Jiri Olsa [Sun, 22 Jul 2012 12:14:39 +0000 (14:14 +0200)]
perf symbols: Add dso data caching
Adding dso data caching so we don't need to open/read/close, each time
we want dso data.
The DSO data caching affects following functions:
dso__data_read_offset
dso__data_read_addr
Each DSO read tries to find the data (based on offset) inside the cache.
If it's not present it fills the cache from file, and returns the data.
If it is present, data are returned with no file read.
Each data read is cached by reading cache page sized/aligned amount of
DSO data. The cache page size is hardcoded to 4096. The cache is using
RB tree with file offset as a sort key.
Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Arun Sharma <asharma@fb.com> Cc: Benjamin Redelings <benjamin.redelings@nescent.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Robert Richter <robert.richter@amd.com> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Ulrich Drepper <drepper@gmail.com> Link: http://lkml.kernel.org/r/1342959280-5361-17-git-send-email-jolsa@redhat.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Jiri Olsa [Sun, 22 Jul 2012 12:14:33 +0000 (14:14 +0200)]
perf symbols: Add interface to read DSO image data
Adding following interface for DSO object to allow
reading of DSO image data:
dso__data_fd
- opens DSO and returns file descriptor
Binary types are used to locate/open DSO in following order:
DSO_BINARY_TYPE__BUILD_ID_CACHE
DSO_BINARY_TYPE__SYSTEM_PATH_DSO
In other word we first try to open DSO build-id path,
and if that fails we try to open DSO system path.
dso__data_read_offset
- reads DSO data from specified offset
dso__data_read_addr
- reads DSO data from specified address/map.
Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Arun Sharma <asharma@fb.com> Cc: Benjamin Redelings <benjamin.redelings@nescent.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Cyrill Gorcunov <gorcunov@openvz.org> Cc: Frank Ch. Eigler <fche@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Robert Richter <robert.richter@amd.com> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> Cc: Ulrich Drepper <drepper@gmail.com> Link: http://lkml.kernel.org/r/1342959280-5361-11-git-send-email-jolsa@redhat.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
perf tools: Fix trace events storms due to weight demux
Trace events have a period (weight) of 1 by default. This can be
overriden on events definition by using the __perf_count() macro.
For example, the sched_stat_runtime() is weighted with the runtime of
the task that fired the event.
By default, perf handles such weighted event by dividing it into
individual events carrying a weight of 1. For example if
sched_stat_runtime is fired and the task has run 5000000 nsecs, perf
divides it into 5000000 events in the buffer.
This behaviour makes weighted events unusable because they quickly
fullfill the buffers and we lose most events.
The commit 5d81e5cfb37a174e8ddc0413e2e70cdf05807ace ("events: Don't
divide events if it has field period") solves this problem by sending
only one event when PERF_SAMPLE_PERIOD flag is set. The weight is
carried in the sample itself such that we don't need to demultiplex it
anymore.
This patch provides the last missing piece to use this feature by
setting PERF_SAMPLE_PERIOD from perf tools when we deal with trace
events.
Before:
$ ./perf record -e sched:* -a sleep 1
[ perf record: Woken up 3 times to write data ]
[ perf record: Captured and wrote 1.619 MB perf.data (~70749 samples) ]
Warning:
Processed 16909 events and lost 1 chunks!
After:
$ ./perf record -e sched:* -a sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.074 MB perf.data (~3228 samples) ]
David Ahern [Fri, 20 Jul 2012 23:25:51 +0000 (17:25 -0600)]
perf kvm: Limit repetitive guestmount message to once per directory
After 7ed97ad use of the guestmount option without a subdir for *each*
VM generates an error message for each sample related to that VM. Once
per VM is enough.
Signed-off-by: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1342826756-64663-7-git-send-email-dsahern@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
After a maddening 2 days sifting through perf minutia I found it --
id_hdr_size is not initialized for guest machines. This shows up on the
report side as random garbage for the cpu and timestamp, e.g.,
David Ahern [Fri, 20 Jul 2012 23:25:47 +0000 (17:25 -0600)]
perf kvm: Set name for VM process in guest machine
COMM events are not generated in the context of a guest machine, so the
thread name is never set for the VMM process. For example, the qemu-kvm
name applies to the process in the host machine, not the guest machine.
So, samples for guest machines are currently displayed as:
99.67% :5671 [unknown] [g] 0xffffffff81366b41
where 5671 is the pid of the VMM. With this patch the samples in the guest
machine are shown as:
Thomas Gleixner [Fri, 13 Jul 2012 17:29:45 +0000 (19:29 +0200)]
genirq: Allow irq chips to mark themself oneshot safe
Some interrupt chips like MSI are oneshot safe by implementation. For
those interrupts we can avoid the mask/unmask sequence for threaded
interrupt handlers.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1207132056540.32033@ionos Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Avi Kivity <avi@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Jan Kiszka <jan.kiszka@web.de>
John Stultz [Mon, 23 Jul 2012 20:22:37 +0000 (16:22 -0400)]
time: Fix casting issue in tk_set_xtime and tk_xtime_add
commit 1e75fa8b (time: Condense timekeeper.xtime into xtime_sec)
introduced helper functions which apply a timespec to the core
internal timekeeper data. The internal storage type is u64. The
timespec tv_nsec value must be shifted before set or added to the
internal value. tv_nsec is a long, which is 32bit on a 32bit system,
so without casting tv_nsec to u64 we lose the bits which are shifted
over the 32bit boundary.
Add the proper typecasts.
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Tested-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Acked-by: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1343074957-16541-1-git-send-email-john.stultz@linaro.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Darren Hart [Fri, 20 Jul 2012 18:53:31 +0000 (11:53 -0700)]
futex: Forbid uaddr == uaddr2 in futex_wait_requeue_pi()
If uaddr == uaddr2, then we have broken the rule of only requeueing
from a non-pi futex to a pi futex with this call. If we attempt this,
as the trinity test suite manages to do, we miss early wakeups as
q.key is equal to key2 (because they are the same uaddr). We will then
attempt to dereference the pi_mutex (which would exist had the futex_q
been properly requeued to a pi futex) and trigger a NULL pointer
dereference.
Darren Hart [Fri, 20 Jul 2012 18:53:30 +0000 (11:53 -0700)]
futex: Fix bug in WARN_ON for NULL q.pi_state
The WARN_ON in futex_wait_requeue_pi() for a NULL q.pi_state was testing
the address (&q.pi_state) of the pointer instead of the value
(q.pi_state) of the pointer. Correct it accordingly.
Peter Zijlstra [Fri, 22 Jun 2012 11:36:05 +0000 (13:36 +0200)]
sched: Fix race in task_group()
Stefan reported a crash on a kernel before a3e5d1091c1 ("sched:
Don't call task_group() too many times in set_task_rq()"), he
found the reason to be that the multiple task_group()
invocations in set_task_rq() returned different values.
Looking at all that I found a lack of serialization and plain
wrong comments.
The below tries to fix it using an extra pointer which is
updated under the appropriate scheduler locks. Its not pretty,
but I can't really see another way given how all the cgroup
stuff works.
Reported-and-tested-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1340364965.18025.71.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
sched: Improve balance_cpu() to consider other cpus in its group as target of (pinned) task
Current load balance scheme requires only one cpu in a
sched_group (balance_cpu) to look at other peer sched_groups for
imbalance and pull tasks towards itself from a busy cpu. Tasks
thus pulled by balance_cpu could later get picked up by cpus
that are in the same sched_group as that of balance_cpu.
This scheme however fails to pull tasks that are not allowed to
run on balance_cpu (but are allowed to run on other cpus in its
sched_group). That can affect fairness and in some worst case
scenarios cause starvation.
Consider a two core (2 threads/core) system running tasks as
below:
Core0 Core1
/ \ / \
C0 C1 C2 C3
| | | |
v v v v
F0 T1 F1 [idle]
T2
F0 = SCHED_FIFO task (pinned to C0)
F1 = SCHED_FIFO task (pinned to C2)
T1 = SCHED_OTHER task (pinned to C1)
T2 = SCHED_OTHER task (pinned to C1 and C2)
F1 could become a cpu hog, which will starve T2 unless C1 pulls
it. Between C0 and C1 however, C0 is required to look for
imbalance between cores, which will fail to pull T2 towards
Core0. T2 will starve eternally in this case. The same scenario
can arise in presence of non-rt tasks as well (say we replace F1
with high irq load).
We tackle this problem by having balance_cpu move pinned tasks
to one of its sibling cpus (where they can run). We first check
if load balance goal can be met by ignoring pinned tasks,
failing which we retry move_tasks() with a new env->dst_cpu.
This patch modifies load balance semantics on who can move load
towards a given cpu in a given sched_domain.
Before this patch, a given_cpu or a ilb_cpu acting on behalf of
an idle given_cpu is responsible for moving load to given_cpu.
With this patch applied, balance_cpu can in addition decide on
moving some load to a given_cpu.
There is a remote possibility that excess load could get moved
as a result of this (balance_cpu and given_cpu/ilb_cpu deciding
*independently* and at *same* time to move some load to a
given_cpu). However we should see less of such conflicting
decisions in practice and moreover subsequent load balance
cycles should correct the excess load moved to given_cpu.
sched: Reset loop counters if all tasks are pinned and we need to redo load balance
While load balancing, if all tasks on the source runqueue are pinned,
we retry after excluding the corresponding source cpu. However, loop counters
env.loop and env.loop_break are not reset before retrying, which can lead
to failure in moving the tasks. In this patch we reset env.loop and
env.loop_break to their inital values before we retry.
sched: Reorder 'struct lb_env' members to reduce its size
Members of 'struct lb_env' are not in appropriate order to reuse compiler
added padding on 64bit architectures. In this patch we reorder those struct
members and help reduce the size of the structure from 96 bytes to 80
bytes on 64 bit architectures.
Mike Galbraith [Tue, 12 Jun 2012 03:18:32 +0000 (05:18 +0200)]
sched: Improve scalability via 'CPU buddies', which withstand random perturbations
Traversing an entire package is not only expensive, it also leads to tasks
bouncing all over a partially idle and possible quite large package. Fix
that up by assigning a 'buddy' CPU to try to motivate. Each buddy may try
to motivate that one other CPU, if it's busy, tough, it may then try its
SMT sibling, but that's all this optimization is allowed to cost.
Sibling cache buddies are cross-wired to prevent bouncing.
4 socket 40 core + SMT Westmere box, single 30 sec tbench runs, higher is better:
Srivatsa S. Bhat [Thu, 24 May 2012 14:17:03 +0000 (19:47 +0530)]
cpusets: Remove/update outdated comments
cpuset_track_online_cpus() is no longer present. So remove the
outdated comment and replace it with reference to cpuset_update_active_cpus()
which is its equivalent.
Also, we don't lack memory hot-unplug anymore. And David Rientjes pointed
out how it is dealt with. So update that comment as well.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20120524141700.3692.98192.stgit@srivatsabhat.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Srivatsa S. Bhat [Thu, 24 May 2012 14:16:55 +0000 (19:46 +0530)]
cpusets, hotplug: Restructure functions that are invoked during hotplug
Separate out the cpuset related handling for CPU/Memory online/offline.
This also helps us exploit the most obvious and basic level of optimization
that any notification mechanism (CPU/Mem online/offline) has to offer us:
"We *know* why we have been invoked. So stop pretending that we are lost,
and do only the necessary amount of processing!".
And while at it, rename scan_for_empty_cpusets() to
scan_cpusets_upon_hotplug(), which is more appropriate considering how
it is restructured.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20120524141650.3692.48637.stgit@srivatsabhat.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Srivatsa S. Bhat [Thu, 24 May 2012 14:16:41 +0000 (19:46 +0530)]
cpusets, hotplug: Implement cpuset tree traversal in a helper function
At present, the functions that deal with cpusets during CPU/Mem hotplug
are quite messy, since a lot of the functionality is mixed up without clear
separation. And this takes a toll on optimization as well. For example,
the function cpuset_update_active_cpus() is called on both CPU offline and CPU
online events; and it invokes scan_for_empty_cpusets(), which makes sense
only for CPU offline events. And hence, the current code ends up unnecessarily
traversing the cpuset tree during CPU online also.
As a first step towards cleaning up those functions, encapsulate the cpuset
tree traversal in a helper function, so as to facilitate upcoming changes.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20120524141635.3692.893.stgit@srivatsabhat.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Srivatsa S. Bhat [Thu, 24 May 2012 14:16:26 +0000 (19:46 +0530)]
CPU hotplug, cpusets, suspend: Don't modify cpusets during suspend/resume
In the event of CPU hotplug, the kernel modifies the cpusets' cpus_allowed
masks as and when necessary to ensure that the tasks belonging to the cpusets
have some place (online CPUs) to run on. And regular CPU hotplug is
destructive in the sense that the kernel doesn't remember the original cpuset
configurations set by the user, across hotplug operations.
However, suspend/resume (which uses CPU hotplug) is a special case in which
the kernel has the responsibility to restore the system (during resume), to
exactly the same state it was in before suspend.
In order to achieve that, do the following:
1. Don't modify cpusets during suspend/resume. At all.
In particular, don't move the tasks from one cpuset to another, and
don't modify any cpuset's cpus_allowed mask. So, simply ignore cpusets
during the CPU hotplug operations that are carried out in the
suspend/resume path.
2. However, cpusets and sched domains are related. We just want to avoid
altering cpusets alone. So, to keep the sched domains updated, build
a single sched domain (containing all active cpus) during each of the
CPU hotplug operations carried out in s/r path, effectively ignoring
the cpusets' cpus_allowed masks.
(Since userspace is frozen while doing all this, it will go unnoticed.)
3. During the last CPU online operation during resume, build the sched
domains by looking up the (unaltered) cpusets' cpus_allowed masks.
That will bring back the system to the same original state as it was in
before suspend.
Ultimately, this will not only solve the cpuset problem related to suspend
resume (ie., restores the cpusets to exactly what it was before suspend, by
not touching it at all) but also speeds up suspend/resume because we avoid
running cpuset update code for every CPU being offlined/onlined.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20120524141611.3692.20155.stgit@srivatsabhat.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Peter Zijlstra [Wed, 13 Jun 2012 13:24:45 +0000 (15:24 +0200)]
sched/x86: Remove broken power estimation
The x86 sched power implementation has been broken forever and gets in
the way of other stuff, remove it.
[ For archaeological interest, fixing this code would require dealing
with the cross-cpu calling of these functions and more importantly, we
need to filter idle time out of the a/m-perf stuff because the ratio
will go down to 0 when idle, giving a 0 capacity which is not what
we'd want. ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Arjan van de Ven <arjan@linux.intel.com> Link: http://lkml.kernel.org/r/1339594110.8980.38.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org>
H. Peter Anvin [Mon, 23 Jul 2012 23:16:17 +0000 (16:16 -0700)]
x86, doc: Assign a bootloader ID for "Minimal Linux Bootloader"
Assign a bootloader ID for Sebastian Plotz' "Minimal Linux Bootloader"
(http://sebastian-plotz.blogspot.de). Sebastian has agreed to make
this the pilot for the use of extended boot loader IDs, so this is
assigned version ID 0x11 (avoid assigning 0x10 for now to catch bugs
with people putting E in the primary ID but leaving the extended ID as
zero.)
Merge branch 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull a x86/build change from Ingo Molnar.
This makes the default stack alignment on x86-64 be just 8, allowing for
improved code generation (it can avoid some unnecessary extra alignment
logic and use just pure push/pop sequences) and smaller stack frames.
We can't generally do SSE with 16-byte alignment issues in the kernel anyway.
* 'x86-build-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86-64, gcc: Use -mpreferred-stack-boundary=3 if supported
Merge branch 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/uv changes from Ingo Molnar:
"UV2 BAU productization fixes.
The BAU (Broadcast Assist Unit) is SGI's fancy out of line way on UV
hardware to do TLB flushes, instead of the normal APIC IPI methods.
The commits here fix / work around hangs in their latest hardware
iteration (UV2).
My understanding is that the main purpose of the out of line
signalling channel is to improve scalability: the UV APIC hardware
glue does not handle broadcasting to many CPUs very well, and this
matters most for TLB shootdowns.
[ I don't agree with all aspects of the current approach: in hindsight
it would have been better to link the BAU at the IPI/APIC driver
level instead of the TLB shootdown level, where TLB flushes are
really just one of the uses of broadcast SMP messages. Doing that
would improve scalability in some other ways and it would also
remove a few uglies from the TLB path. It would also be nice to
push more is_uv_system() tests into proper x86_init or x86_platform
callbacks. Cliff? ]"
* 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/uv: Work around UV2 BAU hangs
x86/uv: Implement UV BAU runtime enable and disable control via /proc/sgi_uv/
x86/uv: Fix the UV BAU destination timeout period
Merge branch 'x86-reboot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/reboot changes from Ingo Molnar:
"Now that the revampted x86 real-mode trampoline code is upstream and
seems to be working well, we can extend the 64-bit reboot code to be
as capable as the 32-bit one."
* 'x86-reboot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86-64, reboot: Be more paranoid in 64-bit reboot=bios
x86, reboot: Drop redundant write of reboot_mode
x86-64, reboot: Allow reboot=bios and reboot-cpu override on x86-64
Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 platform changes from Ingo Molnar:
"This tree mostly involves various APIC driver cleanups/robustization,
and vSMP motivated platform callback improvements/cleanups"
Fix up trivial conflict due to printk cleanup right next to return value
change.
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (29 commits)
Revert "x86/early_printk: Replace obsolete simple_strtoul() usage with kstrtoint()"
x86/apic/x2apic: Use multiple cluster members for the irq destination only with the explicit affinity
x86/apic/x2apic: Limit the vector reservation to the user specified mask
x86/apic: Optimize cpu traversal in __assign_irq_vector() using domain membership
x86/vsmp: Fix vector_allocation_domain's return value
irq/apic: Use config_enabled(CONFIG_SMP) checks to clean up irq_set_affinity() for UP
x86/vsmp: Fix linker error when CONFIG_PROC_FS is not set
x86/apic/es7000: Make apicid of a cluster (not CPU) from a cpumask
x86/apic/es7000+summit: Always make valid apicid from a cpumask
x86/apic/es7000+summit: Fix compile warning in cpu_mask_to_apicid()
x86/apic: Fix ugly casting and branching in cpu_mask_to_apicid_and()
x86/apic: Eliminate cpu_mask_to_apicid() operation
x86/x2apic/cluster: Vector_allocation_domain() should return a value
x86/apic/irq_remap: Silence a bogus pr_err()
x86/vsmp: Ignore IOAPIC IRQ affinity if possible
x86/apic: Make cpu_mask_to_apicid() operations check cpu_online_mask
x86/apic: Make cpu_mask_to_apicid() operations return error code
x86/apic: Avoid useless scanning thru a cpumask in assign_irq_vector()
x86/apic: Try to spread IRQ vectors to different priority levels
x86/apic: Factor out default vector_allocation_domain() operation
...
Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull debug-for-linus git tree from Ingo Molnar.
Fix up trivial conflict in arch/x86/kernel/cpu/perf_event_intel.c due to
a printk() having changed to a pr_info() differently in the two branches.
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86: Move call to print_modules() out of show_regs()
x86/mm: Mark free_initrd_mem() as __init
x86/microcode: Mark microcode_id[] as __initconst
x86/nmi: Clean up register_nmi_handler() usage
x86: Save cr2 in NMI in case NMIs take a page fault (for i386)
x86: Remove cmpxchg from i386 NMI nesting code
x86: Save cr2 in NMI in case NMIs take a page fault
x86/debug: Add KERN_<LEVEL> to bare printks, convert printks to pr_<level>
Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/asm changes from Ingo Molnar:
"Assorted single-commit improvements, as usual"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/mtrr: Slightly simplify print_mtrr_state()
x86/mm/mtrr: Fix alignment determination in range_to_mtrr()
x86/copy_user_generic: Optimize copy_user_generic with CPU erms feature
x86/alternatives: Use atomic_xchg() instead atomic_dec_and_test() for stop_machine_text_poke()
Merge branch 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer core changes from Ingo Molnar:
"Continued cleanups of the core time and NTP code, plus more nohz work
preparing for tick-less userspace execution."
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
time: Rework timekeeping functions to take timekeeper ptr as argument
time: Move xtime_nsec adjustment underflow handling timekeeping_adjust
time: Move arch_gettimeoffset() usage into timekeeping_get_ns()
time: Refactor accumulation of nsecs to secs
time: Condense timekeeper.xtime into xtime_sec
time: Explicitly use u32 instead of int for shift values
time: Whitespace cleanups per Ingo%27s requests
nohz: Move next idle expiry time record into idle logic area
nohz: Move ts->idle_calls incrementation into strict idle logic
nohz: Rename ts->idle_tick to ts->last_tick
nohz: Make nohz API agnostic against idle ticks cputime accounting
nohz: Separate idle sleeping time accounting from nohz logic
timers: Improve get_next_timer_interrupt()
timers: Add accounting of non deferrable timers
timers: Consolidate base->next_timer update
timers: Create detach_if_pending() and use it
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf events changes from Ingo Molnar:
"- kernel side:
- Intel uncore PMU support for Nehalem and Sandy Bridge CPUs, we
support both the events available via the MSR and via the PCI
access space.
- various uprobes cleanups and restructurings
- PMU driver quirks by microcode version and required x86 microcode
loader cleanups/robustization
- various tracing robustness updates
- static keys: remove obsolete static_branch()
- tooling side:
- GTK browser improvements
- perf report browser: support screenshots to file
- more automated tests
- perf kvm improvements
- perf bench refinements
- build environment improvements
- pipe mode improvements
- libtraceevent updates, we have now hopefully merged most bits with
the out of tree forked code base
... and many other goodies."
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (138 commits)
tracing: Check for allocation failure in __tracing_open()
perf/x86: Fix intel_perfmon_event_mapformatting
jump label: Remove static_branch()
tracepoint: Use static_key_false(), since static_branch() is deprecated
perf/x86: Uncore filter support for SandyBridge-EP
perf/x86: Detect number of instances of uncore CBox
perf/x86: Fix event constraint for SandyBridge-EP C-Box
perf/x86: Use 0xff as pseudo code for fixed uncore event
perf/x86: Save a few bytes in 'struct x86_pmu'
perf/x86: Add a microcode revision check for SNB-PEBS
perf/x86: Improve debug output in check_hw_exists()
perf/x86/amd: Unify AMD's generic and family 15h pmus
perf/x86: Move Intel specific code to intel_pmu_init()
perf/x86: Rename Intel specific macros
perf/x86: Fix USER/KERNEL tagging of samples
perf tools: Split event symbols arrays to hw and sw parts
perf tools: Split out PE_VALUE_SYM parsing token to SW and HW tokens
perf tools: Add empty rule for new line in event syntax parsing
perf test: Use ARRAY_SIZE in parse events tests
tools lib traceevent: Cleanup realloc use
...
Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU changes from Ingo Molnar:
"Quoting from Paul, the major features of this series are:
1. Preventing latency spikes of more than 200 microseconds for
kernels built with NR_CPUS=4096, which is reportedly becoming the
default for some distros. This is a first step, as it does not
help with systems that actually -have- 4096 CPUs (work on this case
is in progress, but is not yet ready for mainline).
This category also includes improving concurrency of rcu_barrier(),
placed here due to conflicts. Posted to LKML at:
https://lkml.org/lkml/2012/6/22/381
Note that patches 18-22 of that series have been defered to 3.7, as
they have not yet proven themselves to be mainline-ready (and yes,
these are the ones intended to get rid of RCU's latency spikes for
systems that actually have 4096 CPUs).
2. Updates to documentation and rcutorture fixes, the latter category
including improvements to rcu_barrier() testing. Posted to LKML at
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (48 commits)
rcu: Fix broken strings in RCU's source code.
rcu: Fix code-style issues involving "else"
rcu: Introduce check for callback list/count mismatch
rcu: Make RCU_FAST_NO_HZ respect nohz= boot parameter
rcu: Fix qlen_lazy breakage
rcu: Round FAST_NO_HZ lazy timeout to nearest second
rcu: The rcu_needs_cpu() function is not a quiescent state
rcu: Dump only the current CPU's buffers for idle-entry/exit warnings
rcu: Add check for CPUs going offline with callbacks queued
rcu: Disable preemption in rcu_blocking_is_gp()
rcu: Prevent uninitialized string in RCU CPU stall info
rcu: Fix rcu_is_cpu_idle() #ifdef in TINY_RCU
rcu: Split RCU core processing out of __call_rcu()
rcu: Prevent __call_rcu() from invoking RCU core on offline CPUs
rcu: Make __call_rcu() handle invocation from idle
rcu: Remove function versions of __kfree_rcu and __is_kfree_rcu_offset
rcu: Consolidate tree/tiny __rcu_read_{,un}lock() implementations
rcu: Remove return value from rcu_assign_pointer()
key: Remove extraneous parentheses from rcu_assign_keypointer()
rcu: Remove return value from RCU_INIT_POINTER()
...
Merge branch 'core-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core/iommu changes from Ingo Molnar.
* 'core-iommu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
iommu/dmar: Use pr_format() instead of PREFIX to tidy up pr_*() calls
iommu/dmar: Reserve mmio space used by the IOMMU, if the BIOS forgets to
iommu/dmar: Replace printks with appropriate pr_*()
This commit is subtly buggy: kstrto*int() can return an error but
it's not checked in every path. simple_strtoul() on the other hand
could not fail, so this patch subtly intruduces new failure modes.
CONFIG_EARLY_PRINTK is the only feature that might use command line
parsing in the decompression stage. If it is disabled then we can
exclude the related code to save space. This can result in an estimated
space savings of 2240 bytes from the compressed kernel image.
Joe Millenbach [Fri, 20 Jul 2012 01:04:41 +0000 (18:04 -0700)]
x86, boot: Exclude early_serial_console.c if can't use it.
Removes early_serial_console.c code if we don't have the config option that
enables it (EARLY_PRINTK). When disabling this code, make early_serial_base a
constant 0 to allow the compiler to optimize away the code that checks for
early_serial_base.
Joe Millenbach [Fri, 20 Jul 2012 01:04:40 +0000 (18:04 -0700)]
x86, boot: Removed unused debug flag and set code
As we're no longer using the flag we don't need to extract the value from the
command line and store it. This is a step towards removing command line
parameter code.
Joe Millenbach [Fri, 20 Jul 2012 01:04:39 +0000 (18:04 -0700)]
x86, boot: Switch output functions from command-line flags to conditional compilation
Changed putstr flagging from parameter to conditional compilation for puts,
debug_putstr, and error_putstr. This allows for space savings since most
configurations won't use this feature.
Joe Millenbach [Fri, 20 Jul 2012 01:04:37 +0000 (18:04 -0700)]
x86, boot: Wrap debug printing in a new debug_putstr function
Change all instances of if (debug) putstr(...) to a new debug_putstr(...).
This allows a future change to conditionally stub out debug_putstr to save
space.
Joe Millenbach [Fri, 20 Jul 2012 01:04:36 +0000 (18:04 -0700)]
x86, boot: Removed quiet flag and switched quiet output to debug flag
There are only 3 uses of the quiet flag and they all protect output that
is only useful for debugging the stub, therefore we switched to using the
debug flag for all extra output.
Merge emailed kgdb dmesg fixups patches from Anton Vorontsov:
"The dmesg command appears to be broken after the printk rework. The
old logic in the kdb code makes no sense in terms of current
printk/logging storage format, and KDB simply hangs forever upon
entering 'dmesg' command.
The first patch revives the command by switching to kmsg_dumper
iterator. As a side-effect, the code is now much more simpler.
A few changes were needed in the printk.c: we needed unlocked variant
of the kmsg_dumper iterator, but these can surely wait for 3.6.
It's probably too late even for the first patch to go to 3.5, but I'll
try to convince otherwise. :-) Here we go:
- The current code is broken for sure, and has no hope to work at
all. It is a regression
- The new code works for me, and probably works for everyone else;
- If it compiles (and I urge everyone to compile-test it on your
setup), it hardly can make things worse."
* Merge emailed patches from Anton Vorontsov: (4 commits)
kdb: Switch to nolock variants of kmsg_dump functions
printk: Implement some unlocked kmsg_dump functions
printk: Remove kdb_syslog_data
kdb: Revive dmesg command
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