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Commit f37755490fe9b ("tracepoints: Do not trace when cpu is offline") added
a check to make sure that tracepoints only get called when the cpu is
online, as it uses rcu_read_lock_sched() for protection.
Commit 3a630178fd5f3 ("tracing: generate RCU warnings even when tracepoints
are disabled") added lockdep checks (including rcu checks) for events that
are not enabled to catch possible RCU issues that would only be triggered if
a trace event was enabled. Commit f37755490fe9b only stopped the warnings
when the trace event was enabled but did not prevent warnings if the trace
event was called when disabled.
To fix this, the cpu online check is moved to where the condition is added
to the trace event. This will place the cpu online check in all places that
it may be used now and in the future.
Cc: stable@vger.kernel.org # v3.18+
Fixes: f37755490fe9b ("tracepoints: Do not trace when cpu is offline")
Fixes: 3a630178fd5f3 ("tracing: generate RCU warnings even when tracepoints are disabled")
Reported-by: Sudeep Holla <sudeep.holla@arm.com>
Tested-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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Commit 66b3923a1a0f ("arm64: hugetlb: add support for PTE contiguous bit")
introduced support for huge pages using the contiguous bit in the PTE
as opposed to block mappings, which may be slightly unwieldy (512M) in
64k page configurations.
Unfortunately, this support has resulted in some late regressions when
running the libhugetlbfs test suite with 64k pages and CONFIG_DEBUG_VM
as a result of a BUG:
| readback (2M: 64): ------------[ cut here ]------------
| kernel BUG at fs/hugetlbfs/inode.c:446!
| Internal error: Oops - BUG: 0 [#1] SMP
| Modules linked in:
| CPU: 7 PID: 1448 Comm: readback Not tainted 4.5.0-rc7 #148
| Hardware name: linux,dummy-virt (DT)
| task: fffffe0040964b00 ti: fffffe00c2668000 task.ti: fffffe00c2668000
| PC is at remove_inode_hugepages+0x44c/0x480
| LR is at remove_inode_hugepages+0x264/0x480
Rather than revert the entire patch, simply avoid advertising the
contiguous huge page sizes for now while people are actively working on
a fix. This patch can then be reverted once things have been sorted out.
Cc: David Woods <dwoods@ezchip.com>
Reported-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Some models reduce the number of available isochronous streams for higher
sampling transfer frequency. Such models bring an issue about how to add
PCM substreams. When at lower sampling transfer frequency, the
models reports whole available streams, thus this driver can add enough
number of PCM substreams at probing time. On the other hand, at higher
sampling transfer frequency, this driver can just add reduced number of
PCM substreams. After probed, even if the sampling transfer frequency is
changed to lower rate, fewer PCM substreams are actually available. This
is inconvenience.
For the reason, this commit adds a list so that this driver assume models
on the list to have two pairs of PCM substreams. This list keeps the name
of model in which the number of available streams differs depending on
sampling transfer frequency.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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available
In former commits, ALSA dice driver can handle available isochronous
streams. This commit adds support for several PCM substreams on the
streams.
The additional PCM substreams are available via another ALSA PCM character
devices so that one ALSA PCM application can handle them without cumbersome
operations. For example, two PCM substreams are available on each stream,
two ALSA character devices are added for them. In configuration space of
alsa-lib, it's represented with 'hw:0,0' and 'hw:0,1'.
The PCM substreams are constraint to parameters of the corresponding
streams. If the PCM substreams are unavailable for some reasons,
open(2) to ALSA PCM character device returns error and reports ENXIO.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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This commit enables ALSA dice driver to handle whole available streams.
In Dice, certain registers represent the number of available streams at
current sampling transfer frequency for both directions. The parameters
of each stream are represented in a block of register. This block is
aligned sequentially. These streams start simultaneously by writing
enable bit to a register.
This commit operates these registers when starting/stopping streams.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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Currently ALSA dice driver handles a pair of isochronous resources for
IEC 61883-1/6 packet streaming. While, according to some documents about
ASICs named as 'Dice', several isochronous streams are available.
Here, I start to describe ASICs produced under 'Dice' name.
* Dice II (designed by wavefront semiconductor, including TCAT's IP)
* STD (with limited functionality of DTCP)
* CP (with full functionality of DTCP)
* TCD2210/2210-E (so-called 'Dice Mini')
* TCD2220/2220-E (so-called 'Dice Jr.')
* TCD3070-CH (so-called 'Dice III')
Some documents are public and we can see hardware design of them. We can
find some articles about hardware internal register definitions
(not registers exported to IEEE 1394 bus).
* DICE II User Guide
* http://www.tctechnologies.tc/archive/downloads/dice_ii_user_guide.pdf
* 6.1 AVS Audio Receivers
* Table 6.1: AVS Audio Receiver Memory Map
* ARX1-ARX4
* 6.2 AVS Audio Transmitters
* Table 6.2: AVS Audio Transmitter Memory Map
* ATX1, ATX2
* TCD22xx User Guide
* http://www.tctechnologies.tc/downloads/tcd22xx_user_guide.pdf
* 6.1 AVS Audio Receivers
* Table 66: AVS Audio Receiver Memory Map
* ARX1, ARX2
* 6/2 AVS Audio Transmitters
* Table 67: AVS Audio Transmitter Memory Map
* ATX1, ATX2
* DICE III
* http://www.tctechnologies.tc/downloads/TCD3070-CH.pdf
* Dual stream 63 channel transmitter/receiver
For Dice II and TCD22xx series, maximum 16 data channels are transferred in
an AMDTP packet, while for Dice III, maximum 32 data channels are
transferred.
According to the design of the series of these ASICs, this commit allows
this driver to handle additional set of isochronous resources. For
practical reason, two pair of isochronous resources are added. As of this
commit, this driver still use a pair of the first isochronous resources.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
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I screwed up while merging the immutable branch for TPS65912,
so fixing it unbroken again.
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Andrew F. Davis <afd@ti.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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This reverts commit 3fab91ea284a3b795327dda915a3c150a49e4be2.
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Commit dfd55ad85e4a ("arm64: vmemmap: use virtual projection of linear
region") fixed an issue where the struct page array would overflow into the
adjacent virtual memory region if system RAM was placed so high up in
physical memory that its addresses were not representable in the build time
configured virtual address size.
However, the fix failed to take into account that the vmemmap region needs
to be relatively aligned with respect to the sparsemem section size, so that
a sequence of page structs corresponding with a sparsemem section in the
linear region appears naturally aligned in the vmemmap region.
So round up vmemmap to sparsemem section size. Since this essentially moves
the projection of the linear region up in memory, also revert the reduction
of the size of the vmemmap region.
Cc: <stable@vger.kernel.org>
Fixes: dfd55ad85e4a ("arm64: vmemmap: use virtual projection of linear region")
Tested-by: Mark Langsdorf <mlangsdo@redhat.com>
Tested-by: David Daney <david.daney@cavium.com>
Tested-by: Robert Richter <rrichter@cavium.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
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Use the observation that cpufreq_update_util() is only called
by the scheduler with rq->lock held, so the callers of
cpufreq_set_update_util_data() can use synchronize_sched()
instead of synchronize_rcu() to wait for cpufreq_update_util()
to complete. Moreover, if they are updated to do that,
rcu_read_(un)lock() calls in cpufreq_update_util() might be
replaced with rcu_read_(un)lock_sched(), respectively, but
those aren't really necessary, because the scheduler calls
that function from RCU-sched read-side critical sections
already.
In addition to that, if cpufreq_set_update_util_data() checks
the func field in the struct update_util_data before setting
the per-CPU pointer to it, the data->func check may be dropped
from cpufreq_update_util() as well.
Make the above changes to reduce the overhead from
cpufreq_update_util() in the scheduler paths invoking it
and to make the cleanup after removing its callbacks less
heavy-weight somewhat.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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Commit 0eb463be3436 (cpufreq: governor: Replace timers with utilization
update callbacks) made CPU_FREQ select IRQ_WORK, but that's not
necessary, as it is sufficient for IRQ_WORK to be selected by
CPU_FREQ_GOV_COMMON, so modify the cpufreq Kconfig to that effect.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Rename dma_*_writecombine() to dma_*_wc(), so that the naming
is coherent across the various write-combining APIs. Keep the
old names for compatibility for a while, these can be removed
at a later time. A guard is left to enable backporting of the
rename, and later remove of the old mapping defines seemlessly.
Build tested successfully with allmodconfig.
The following Coccinelle SmPL patch was used for this simple
transformation:
@ rename_dma_alloc_writecombine @
expression dev, size, dma_addr, gfp;
@@
-dma_alloc_writecombine(dev, size, dma_addr, gfp)
+dma_alloc_wc(dev, size, dma_addr, gfp)
@ rename_dma_free_writecombine @
expression dev, size, cpu_addr, dma_addr;
@@
-dma_free_writecombine(dev, size, cpu_addr, dma_addr)
+dma_free_wc(dev, size, cpu_addr, dma_addr)
@ rename_dma_mmap_writecombine @
expression dev, vma, cpu_addr, dma_addr, size;
@@
-dma_mmap_writecombine(dev, vma, cpu_addr, dma_addr, size)
+dma_mmap_wc(dev, vma, cpu_addr, dma_addr, size)
We also keep the old names as compatibility helpers, and
guard against their definition to make backporting easier.
Generated-by: Coccinelle SmPL
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Luis R. Rodriguez <mcgrof@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: airlied@linux.ie
Cc: akpm@linux-foundation.org
Cc: benh@kernel.crashing.org
Cc: bhelgaas@google.com
Cc: bp@suse.de
Cc: dan.j.williams@intel.com
Cc: daniel.vetter@ffwll.ch
Cc: dhowells@redhat.com
Cc: julia.lawall@lip6.fr
Cc: konrad.wilk@oracle.com
Cc: linux-fbdev@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: luto@amacapital.net
Cc: mst@redhat.com
Cc: tomi.valkeinen@ti.com
Cc: toshi.kani@hp.com
Cc: vinod.koul@intel.com
Cc: xen-devel@lists.xensource.com
Link: http://lkml.kernel.org/r/1453516462-4844-1-git-send-email-mcgrof@do-not-panic.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Sync it to the Kconfig default for 32-bit.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: tim.gardner@canonical.com
Link: http://lkml.kernel.org/r/20160309134821.GD6564@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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There's no need to use a const char pointer, we can used char pointer
from the beginning and omit the unnecessary cast.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160308184230.GB7897@krava.redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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The entire sequence of events (like INIT/START or STOP/EXIT) for which
cpufreq_governor() is called, is guaranteed to be protected by
policy->rwsem now.
The additional checks that were added earlier (as we were forced to drop
policy->rwsem before calling cpufreq_governor() for EXIT event), aren't
required anymore.
Over that, they weren't sufficient really. They just take care of
START/STOP events, but not INIT/EXIT and the state machine was never
maintained properly by them.
Kill the unnecessary checks and policy->governor_enabled field.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The __ at the beginning of the routine aren't really necessary at all.
Rename it to cpufreq_governor() instead.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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handle_update() is declared at the top of the file as its user appear
before its definition. Relocate the routine to get rid of this.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The show() and store() routines in the cpufreq-governor core don't need
to check if the struct governor_attr they want to use really provides
the callbacks they need as expected (if that's not the case, it means a
bug in the code anyway), so change them to avoid doing that.
Also change the error value to -EBUSY, if the governor is getting
removed and we aren't allowed to store any more changes.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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There is a scenario that may lead to undesired results in
dbs_update_util_handler(). Namely, if two CPUs sharing a policy
enter the funtion at the same time, pass the sample delay check
and then one of them is stalled until dbs_work_handler() (queued
up by the other CPU) clears the work counter, it may update the
work counter and queue up another work item prematurely.
To prevent that from happening, use the observation that the CPU
queuing up a work item in dbs_update_util_handler() updates the
last sample time. This means that if another CPU was stalling after
passing the sample delay check and now successfully updated the work
counter as a result of the race described above, it will see the new
value of the last sample time which is different from what it used in
the sample delay check before. If that happens, the sample delay
check passed previously is not valid any more, so the CPU should not
continue.
Fixes: f17cbb53783c (cpufreq: governor: Avoid atomic operations in hot paths)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The gov_set_update_util() routine is only used internally by the
common governor code and it doesn't need to be exported, so make
it static.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Since cpufreq_governor_dbs() is now always called with policy->rwsem
held, it cannot be executed twice in parallel for the same policy.
Thus it is not necessary to hold dbs_data_mutex around the invocations
of cpufreq_governor_start/stop/limits() from it as those functions
never modify any data that can be shared between different policies.
However, cpufreq_governor_dbs() may be executed twice in parallal
for different policies using the same gov->gdbs_data object and
dbs_data_mutex is still necessary to protect that object against
concurrent updates.
For this reason, narrow down the dbs_data_mutex locking to
cpufreq_governor_init/exit() where it is needed and rename the
mutex to gov_dbs_data_mutex to reflect its purpose.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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That mutex is only used by cpufreq_governor_dbs() and it doesn't
need to be exported to modules, so make it static and drop the
export incantation.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Move the definitions of struct od_dbs_tuners and struct cs_dbs_tuners
from the common governor header to the ondemand and conservative
governor code, respectively, as they don't need to be in the common
header any more.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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After previous changes there is only one piece of code in the
ondemand governor making references to per-CPU data structures,
but it can be easily modified to avoid doing that, so modify it
accordingly and move the definition of per-CPU data used by the
ondemand and conservative governors to the common code. Next,
change that code to access the per-CPU data structures directly
rather than via a governor callback.
This causes the ->get_cpu_cdbs governor callback to become
unnecessary, so drop it along with the macro and function
definitions related to it.
Finally, drop the definitions of struct od_cpu_dbs_info_s and
struct cs_cpu_dbs_info_s that aren't necessary any more.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Some fields in struct od_cpu_dbs_info_s and struct cs_cpu_dbs_info_s
are only used for a limited set of CPUs. Namely, if a policy is
shared between multiple CPUs, those fields will only be used for one
of them (policy->cpu). This means that they really are per-policy
rather than per-CPU and holding room for them in per-CPU data
structures is generally wasteful. Also moving those fields into
per-policy data structures will allow some significant simplifications
to be made going forward.
For this reason, introduce struct cs_policy_dbs_info and
struct od_policy_dbs_info to hold those fields. Define each of the
new structures as an extension of struct policy_dbs_info (such that
struct policy_dbs_info is embedded in each of them) and introduce
new ->alloc and ->free governor callbacks to allocate and free
those structures, respectively, such that ->alloc() will return
a pointer to the struct policy_dbs_info embedded in the allocated
data structure and ->free() will take that pointer as its argument.
With that, modify the code accessing the data fields in question
in per-CPU data objects to look for them in the new structures
via the struct policy_dbs_info pointer available to it and drop
them from struct od_cpu_dbs_info_s and struct cs_cpu_dbs_info_s.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The ondemand_powersave_bias_init() function used for resetting data
fields related to the powersave bias tunable of the ondemand governor
works by walking all of the online CPUs in the system and updating the
od_cpu_dbs_info_s structures for all of them.
However, if governor tunables are per policy, the update should not
touch the CPUs that are not associated with the given dbs_data.
Moreover, since the data fields in question are only ever used for
policy->cpu in each policy governed by ondemand, the update can be
limited to those specific CPUs.
Rework the code to take the above observations into account.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The ->store() callbacks of some tunable sysfs attributes of the
ondemand and conservative governors trigger immediate updates of
the CPU load information for all CPUs "governed" by the given
dbs_data by walking the cpu_dbs_info structures for all online
CPUs in the system and updating them.
This is questionable for two reasons. First, it may lead to a lot of
extra overhead on a system with many CPUs if the given dbs_data is
only associated with a few of them. Second, if governor tunables are
per-policy, the CPUs associated with the other sets of governor
tunables should not be updated.
To address this issue, use the observation that in all of the places
in question the update operation may be carried out in the same way
(because all of the tunables involved are now located in struct
dbs_data and readily available to the common code) and make the
code in those places invoke the same (new) helper function that
will carry out the update correctly.
That new function always checks the ignore_nice_load tunable value
and updates the CPUs' prev_cpu_nice data fields if that's set, which
wasn't done by the original code in store_io_is_busy(), but it
should have been done in there too.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The ->powersave_bias_init_cpu callback in struct od_ops is only used
in one place and that invocation may be replaced with a direct call
to the function pointed to by that callback, so change the code
accordingly and drop the callback.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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After some previous changes, the ->get_cpu_dbs_info_s governor
callback and the "governor" field in struct dbs_governor (whose
value represents the governor type) are not used any more, so
drop them.
Also drop the unused gov_ops field from struct dbs_governor.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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To avoid having to check the governor type explicitly in the common
code in order to initialize data structures specific to the governor
type properly, add a ->start callback to struct dbs_governor and
use it to initialize those data structures for the ondemand and
conservative governors.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The io_is_busy governor tunable is only used by the ondemand governor
and is located in the ondemand-specific data structure, but it is
looked at by the common governor code that has to do ugly things to
get to that value, so move it to struct dbs_data and modify ondemand
accordingly.
Since the conservative governor never touches that field, it will
be always 0 for that governor and it won't have any effect on the
results of computations in that case.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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It is possible for a dbs_data object to be updated after its
usage counter has become 0. That may happen if governor_store()
runs (via a govenor tunable sysfs attribute write) in parallel
with cpufreq_governor_exit() called for the last cpufreq policy
associated with the dbs_data in question. In that case, if
governor_store() acquires dbs_data->mutex right after
cpufreq_governor_exit() has released it, the ->store() callback
invoked by it may operate on dbs_data with no users. Although
sysfs will cause the kobject_put() in cpufreq_governor_exit() to
block until governor_store() has returned, that situation may
lead to some unexpected results, depending on the implementation
of the ->store callback, and therefore it should be avoided.
To that end, modify governor_store() to check the dbs_data's
usage count before invoking the ->store() callback and return
an error if it is 0 at that point.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The ->freq_increase callback in struct od_ops is never invoked,
so drop it.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Drop some lines of code from od_update() by arranging the statements
in there in a more logical way.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Do not convert microseconds to jiffies and the other way around
in governor computations related to the sampling rate and sample
delay and drop delay_for_sampling_rate() which isn't of any use
then.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Reduce the indentation level in the conditionals in od_dbs_timer()
and drop the delay variable from it.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org>
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The rate_mult field in struct od_cpu_dbs_info_s is used by the code
shared with the conservative governor and to access it that code
has to do an ugly governor type check. However, first of all it
is ever only used for policy->cpu, so it is per-policy rather than
per-CPU and second, it is initialized to 1 by cpufreq_governor_start(),
so if the conservative governor never modifies it, it will have no
effect on the results of any computations.
For these reasons, move rate_mult to struct policy_dbs_info (as a
common field).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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If store_sampling_rate() updates the sample delay when the ondemand
governor is in the middle of its high/low dance (OD_SUB_SAMPLE sample
type is set), the governor will still do the bottom half of the
previous sample which may take too much time.
To prevent that from happening, change store_sampling_rate() to always
reset the sample delay to 0 which also is consistent with the new
behavior of cpufreq_governor_limits().
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The way the ->gov_check_cpu governor callback is used by the ondemand
and conservative governors is not really straightforward. Namely, the
governor calls dbs_check_cpu() that updates the load information for
the policy and the invokes ->gov_check_cpu() for the governor.
To get rid of that entanglement, notice that cpufreq_governor_limits()
doesn't need to call dbs_check_cpu() directly. Instead, it can simply
reset the sample delay to 0 which will cause a sample to be taken
immediately. The result of that is practically equivalent to calling
dbs_check_cpu() except that it will trigger a full update of governor
internal state and not just the ->gov_check_cpu() part.
Following that observation, make cpufreq_governor_limits() reset
the sample delay and turn dbs_check_cpu() into a function that will
simply evaluate the load and return the result called dbs_update().
That function can now be called by governors from the routines that
previously were pointed to by ->gov_check_cpu and those routines
can be called directly by each governor instead of dbs_check_cpu().
This way ->gov_check_cpu becomes unnecessary, so drop it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Clean up some load-related computations in dbs_check_cpu() and
cpufreq_governor_start() to get rid of unnecessary operations and
type casts and make the code easier to read.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The contribution of the CPU nice time to the idle time in dbs_check_cpu()
is computed in a bogus way, as the code may subtract current and previous
nice values for different CPUs.
That doesn't matter for cases when cpufreq policies are not shared,
but may lead to problems otherwise.
Fix the computation and simplify it to avoid taking unnecessary steps.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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Rework the handling of work items by dbs_update_util_handler() and
dbs_work_handler() so the former (which is executed in scheduler
paths) only uses atomic operations when absolutely necessary. That
is, when the policy is shared and dbs_update_util_handler() has
already decided that this is the time to queue up a work item.
In particular, this avoids the atomic ops entirely on platforms where
policy objects are never shared.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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The atomic work counter incrementation in gov_cancel_work() is not
necessary any more, because work items won't be queued up after
gov_clear_update_util() anyway, so drop it along with the comment
about how it may be missed by the gov_clear_update_util().
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
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As it turns out, irq_work_queue_on() will crash if invoked on
non-SMP ARM platforms, but in fact it is not necessary to use that
function in the cpufreq governor code (as it doesn't matter to that
code which CPU will handle the irq_work), so change it to always use
irq_work_queue().
Fixes: 8fb47ff100af (cpufreq: governor: Replace timers with utilization update callbacks)
Reported-and-tested-by: Guenter Roeck <linux@roeck-us.net>
Reported-and-tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Avoid extra checks in od_dbs_timer() by rearranging updates to the
local delay variable in it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The ondemand governor already updates sample_delay_ns immediately on
updates to the sampling rate, but conservative doesn't do that.
It was left out earlier as the code was really too complex to get
that done easily. Things are sorted out very well now, however, and
the conservative governor can be modified to follow ondemand in that
respect.
Moreover, since the code needed to implement that in the
conservative governor would be identical to the corresponding
ondemand governor's code, make that code common and change both
governors to use it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Juri Lelli <juri.lelli@arm.com>
Tested-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq core now guarantees that policy->rwsem won't be dropped
while running the ->governor callback for the CPUFREQ_GOV_POLICY_EXIT
event and will be held acquired until the complete sequence of governor
state changes has finished.
This allows governor state machine checks to be dropped from multiple
functions in cpufreq_governor.c.
This also means that policy_dbs->policy can be initialized upfront, so
the entire initialization of struct policy_dbs can be carried out in
one place.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Juri Lelli <juri.lelli@arm.com>
Tested-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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We used to drop policy->rwsem just before calling __cpufreq_governor()
in some cases earlier and so it was possible that __cpufreq_governor()
ran concurrently via separate threads for the same policy.
In order to guarantee valid state transitions for governors,
'governor_enabled' was required to be protected using some locking
and cpufreq_governor_lock was added for that.
But now __cpufreq_governor() is always called under policy->rwsem,
and 'governor_enabled' is protected against races even without
cpufreq_governor_lock.
Get rid of the extra lock now.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Juri Lelli <juri.lelli@arm.com>
Tested-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
[ rjw : Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The cpufreq core code is not consistent with respect to invoking
__cpufreq_governor() under policy->rwsem.
Changing all code to always hold policy->rwsem around
__cpufreq_governor() invocations will allow us to remove
cpufreq_governor_lock that is used today because we can't
guarantee that __cpufreq_governor() isn't executed twice in
parallel for the same policy.
We should also ensure that policy->rwsem is held across governor
state changes.
For example, while adding a CPU to the policy in the CPU online path,
we need to stop the governor, change policy->cpus, start the governor
and then refresh its limits. The complete sequence must be guaranteed
to complete without interruptions by concurrent governor state
updates. That can be achieved by holding policy->rwsem around those
sequences of operations.
Also note that after this patch cpufreq_driver->stop_cpu() and
->exit() will get called under policy->rwsem which wasn't the case
earlier. That shouldn't have any side effects, though.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Juri Lelli <juri.lelli@arm.com>
Tested-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Commit 1aee40ac9c86 (cpufreq: Invoke __cpufreq_remove_dev_finish()
after releasing cpu_hotplug.lock) split the cpufreq's CPU offline
routine in two pieces, one of them to be run with CPU offline/online
locked and the other to be called later. The reason for that split
was a possible deadlock scenario involving cpufreq sysfs attributes
and CPU offline.
However, the handling of CPU offline in cpufreq has changed since
then. Policy sysfs attributes are never removed during CPU offline,
so there's no need to worry about accessing them during CPU offline,
because that can't lead to any deadlocks now. Governor sysfs
attributes are still removed in __cpufreq_governor(_EXIT), but
there is a new kobject type for them now and its show/store
callbacks don't lock CPU offline/online (they don't need to do
that).
This means that the CPU offline code in cpufreq doesn't need to
be split any more, so combine cpufreq_offline_prepare() with
cpufreq_offline_finish().
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Tested-by: Juri Lelli <juri.lelli@arm.com>
Tested-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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