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The runtime modified EM table can be provided from drivers. Create
mechanism which allows safely allocate and free the table for device
drivers. The same table can be used by the EAS in task scheduler code
paths, so make sure the memory is not freed when the device driver module
is unloaded.
Reviewed-by: Dietmar Eggemann <[email protected]>
Tested-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Lukasz Luba <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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The new runtime table can be populated with a new power data to better
reflect the actual efficiency of the device e.g. CPU. The power can vary
over time e.g. due to the SoC temperature change. Higher temperature can
increase power values. For longer running scenarios, such as game or
camera, when also other devices are used (e.g. GPU, ISP) the CPU power can
change. The new EM framework is able to addresses this issue and change
the EM data at runtime safely.
Reviewed-by: Dietmar Eggemann <[email protected]>
Tested-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Lukasz Luba <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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Split the process of allocation and data initialization for the EM table.
The upcoming changes for modifiable EM will use it.
This change is not expected to alter the general functionality.
Reviewed-by: Dietmar Eggemann <[email protected]>
Tested-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Lukasz Luba <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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Subsequent changes will introduce a case in which 'cb->get_cost' may
not be set in em_compute_costs(), so add a check to ensure that it is
not NULL before attempting to dereference it.
Reviewed-by: Dietmar Eggemann <[email protected]>
Tested-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Lukasz Luba <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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Move the EM costs computation code into a new dedicated function,
em_compute_costs(), that can be reused in other places in the future.
This change is not expected to alter the general functionality.
Reviewed-by: Dietmar Eggemann <[email protected]>
Tested-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Lukasz Luba <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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The Energy Model might be updated at runtime and the energy efficiency
for each OPP may change. Thus, there is a need to update also the
cpufreq framework and make it aligned to the new values. In order to
do that, use a first active CPU from the Performance Domain. This is
needed since the first CPU in the cpumask might be offline when we
run this code path.
Reviewed-by: Hongyan Xia <[email protected]>
Reviewed-by: Dietmar Eggemann <[email protected]>
Tested-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Lukasz Luba <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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In order to prepare the code for the modifiable EM perf_state table,
make em_cpufreq_update_efficiencies() take a pointer to the EM table
as its second argument and modify it to use that new argument instead
of the 'table' member of dev->em_pd.
No functional impact.
Reviewed-by: Hongyan Xia <[email protected]>
Reviewed-by: Dietmar Eggemann <[email protected]>
Tested-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Lukasz Luba <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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Fix missing newline for the string long in the error code path.
Reviewed-by: Hongyan Xia <[email protected]>
Reviewed-by: Dietmar Eggemann <[email protected]>
Tested-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Lukasz Luba <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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After the recent changes nobody use siglock to read the values protected
by stats_lock, we can kill spin_lock_irq(¤t->sighand->siglock) and
update the comment.
With this patch only __exit_signal() and thread_group_start_cputime() take
stats_lock under siglock.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Oleg Nesterov <[email protected]>
Signed-off-by: Dylan Hatch <[email protected]>
Cc: Eric W. Biederman <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
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lock_task_sighand() can trigger a hard lockup. If NR_CPUS threads call
getrusage() at the same time and the process has NR_THREADS, spin_lock_irq
will spin with irqs disabled O(NR_CPUS * NR_THREADS) time.
Change getrusage() to use sig->stats_lock, it was specifically designed
for this type of use. This way it runs lockless in the likely case.
TODO:
- Change do_task_stat() to use sig->stats_lock too, then we can
remove spin_lock_irq(siglock) in wait_task_zombie().
- Turn sig->stats_lock into seqcount_rwlock_t, this way the
readers in the slow mode won't exclude each other. See
https://lore.kernel.org/all/[email protected]/
- stats_lock has to disable irqs because ->siglock can be taken
in irq context, it would be very nice to change __exit_signal()
to avoid the siglock->stats_lock dependency.
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Oleg Nesterov <[email protected]>
Reported-by: Dylan Hatch <[email protected]>
Tested-by: Dylan Hatch <[email protected]>
Cc: Eric W. Biederman <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
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Patch series "getrusage: use sig->stats_lock", v2.
This patch (of 2):
thread_group_cputime() does its own locking, we can safely shift
thread_group_cputime_adjusted() which does another for_each_thread loop
outside of ->siglock protected section.
This is also preparation for the next patch which changes getrusage() to
use stats_lock instead of siglock, thread_group_cputime() takes the same
lock. With the current implementation recursive read_seqbegin_or_lock()
is fine, thread_group_cputime() can't enter the slow mode if the caller
holds stats_lock, yet this looks more safe and better performance-wise.
Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Oleg Nesterov <[email protected]>
Reported-by: Dylan Hatch <[email protected]>
Tested-by: Dylan Hatch <[email protected]>
Cc: Eric W. Biederman <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
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'config BPF' exists in both init/Kconfig and kernel/bpf/Kconfig.
Commit b24abcff918a ("bpf, kconfig: Add consolidated menu entry for bpf
with core options") added the second one to kernel/bpf/Kconfig instead
of moving the existing one.
Merge them together.
Signed-off-by: Masahiro Yamada <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Acked-by: Yonghong Song <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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dump_stack() is called in panic(). If for some reason another CPU
is holding the printk_cpu_sync and is unable to release it, the
panic CPU will be unable to continue and print the stacktrace.
Since non-panic CPUs are not allowed to store new printk messages
anyway, there is no need to synchronize the stacktrace output in
a panic situation.
For the panic CPU, do not get the printk_cpu_sync because it is
not needed and avoids a potential deadlock scenario in panic().
Link: https://lore.kernel.org/lkml/ZcIGKU8sxti38Kok@alley
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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If the kernel crashes in a context where printk() calls always
defer printing (such as in NMI or inside a printk_safe section)
then the final panic messages will be deferred to irq_work. But
if irq_work is not available, the messages will not get printed
unless explicitly flushed. The result is that the final
"end Kernel panic" banner does not get printed.
Add one final flush after the last printk() call to make sure
the final panic messages make it out as well.
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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Commit 13fb0f74d702 ("printk: Avoid livelock with heavy printk
during panic") introduced a mechanism to silence non-panic CPUs
if too many messages are being dropped. Aside from trying to
workaround the livelock bugs of legacy consoles, it was also
intended to avoid losing panic messages. However, if non-panic
CPUs are writing to the ringbuffer, then reacting to dropped
messages is too late.
Another motivation is that non-finalized messages already might
be skipped in panic(). In other words, random messages from
non-panic CPUs might already get lost. It is better to ignore
all to avoid confusion.
To avoid losing panic CPU messages, silence non-panic CPUs
immediately on panic.
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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The commit d51507098ff91 ("printk: disable optimistic spin
during panic") added checks to avoid becoming a console waiter
if a panic is in progress.
However, the transition to panic can occur while there is
already a waiter. The current owner should not pass the lock to
the waiter because it might get stopped or blocked anytime.
Also the panic context might pass the console lock owner to an
already stopped waiter by mistake. It might happen when
console_flush_on_panic() ignores the current lock owner, for
example:
CPU0 CPU1
---- ----
console_lock_spinning_enable()
console_trylock_spinning()
[CPU1 now console waiter]
NMI: panic()
panic_other_cpus_shutdown()
[stopped as console waiter]
console_flush_on_panic()
console_lock_spinning_enable()
[print 1 record]
console_lock_spinning_disable_and_check()
[handover to stopped CPU1]
This results in panic() not flushing the panic messages.
Fix these problems by disabling all spinning operations
completely during panic().
Another advantage is that it prevents possible deadlocks caused
by "console_owner_lock". The panic() context does not need to
take it any longer. The lockless checks are safe because the
functions become NOPs when they see the panic in progress. All
operations manipulating the state are still synchronized by the
lock even when non-panic CPUs would notice the panic
synchronously.
The current owner might stay spinning. But non-panic() CPUs
would get stopped anyway and the panic context will never start
spinning.
Fixes: dbdda842fe96 ("printk: Add console owner and waiter logic to load balance console writes")
Signed-off-by: John Ogness <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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Normally a reader will stop once reaching a non-finalized
record. However, when a panic happens, writers from other CPUs
(or an interrupted context on the panic CPU) may have been
writing a record and were unable to finalize it. The panic CPU
will reserve/commit/finalize its panic records, but these will
be located after the non-finalized records. This results in
panic() not flushing the panic messages.
Extend _prb_read_valid() to skip over non-finalized records if
on the panic CPU.
Fixes: 896fbe20b4e2 ("printk: use the lockless ringbuffer")
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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Currently pr_flush() will only wait for records that were
available to readers at the time of the call (using
prb_next_seq()). But there may be more records (non-finalized)
that have following finalized records. pr_flush() should wait
for these to print as well. Particularly because any trailing
finalized records may be the messages that the calling context
wants to ensure are printed.
Add a new ringbuffer function prb_next_reserve_seq() to return
the sequence number following the most recently reserved record.
This guarantees that pr_flush() will wait until all current
printk() messages (completed or in progress) have been printed.
Fixes: 3b604ca81202 ("printk: add pr_flush()")
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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With the lockless ringbuffer, it is allowed that multiple
CPUs/contexts write simultaneously into the buffer. This creates
an ambiguity as some writers will finalize sooner.
The documentation for the prb_read functions is not clear as it
refers to "not yet written" and "no data available". Clarify the
return values and language to be in terms of the reader: records
available for reading.
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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There is already panic_in_progress() and other_cpu_in_panic(),
but checking if the current CPU is the panic CPU must still be
open coded.
Add this_cpu_in_panic() to complete the set.
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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Currently @suppress_panic_printk is checked along with
non-matching @panic_cpu and current CPU. This works
because @suppress_panic_printk is only set when
panic_in_progress() is true.
Rather than relying on the @suppress_panic_printk semantics,
use the concise helper function other_cpu_in_progress(). The
helper function exists to avoid open coding such tests.
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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For empty line records, no data blocks are created. Instead,
these valid records are identified by special logical position
values (in fields of @prb_desc.text_blk_lpos).
Currently the macro NO_LPOS is used for empty line records.
This name is confusing because it does not imply _why_ there is
no data block.
Rename NO_LPOS to EMPTY_LINE_LPOS so that it is clear why there
is no data block.
Also add comments explaining the use of EMPTY_LINE_LPOS as well
as clarification to the values used to represent data-less
blocks.
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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Commit f244b4dc53e5 ("printk: ringbuffer: Improve
prb_next_seq() performance") introduced an optimization for
prb_next_seq() by using best-effort to track recently finalized
records. However, the order of finalization does not
necessarily match the order of the records. The optimization
changed prb_next_seq() to return inconsistent results, possibly
yielding sequence numbers that are not available to readers
because they are preceded by non-finalized records or they are
not yet visible to the reader CPU.
Rather than simply best-effort tracking recently finalized
records, force the committing writer to read records and
increment the last "contiguous block" of finalized records. In
order to do this, the sequence number instead of ID must be
stored because ID's cannot be directly compared.
A new memory barrier pair is introduced to guarantee that a
reader can always read the records up until the sequence number
returned by prb_next_seq() (unless the records have since
been overwritten in the ringbuffer).
This restores the original functionality of prb_next_seq()
while also keeping the optimization.
For 32bit systems, only the lower 32 bits of the sequence
number are stored. When reading the value, it is expanded to
the full 64bit sequence number using the 32bit seq macros,
which fold in the value returned by prb_first_seq().
Fixes: f244b4dc53e5 ("printk: ringbuffer: Improve prb_next_seq() performance")
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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Note: This change only applies to 32bit architectures. On 64bit
architectures the macros are NOPs.
Currently prb_next_seq() is used as the base for the 32bit seq
macros __u64seq_to_ulseq() and __ulseq_to_u64seq(). However, in
a follow-up commit, prb_next_seq() will need to make use of the
32bit seq macros.
Use prb_first_seq() as the base for the 32bit seq macros instead
because it is guaranteed to return 64bit sequence numbers without
relying on any 32bit seq macros.
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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Note: This change only applies to 32bit architectures. On 64bit
architectures the macros are NOPs.
__ulseq_to_u64seq() computes the upper 32 bits of the passed
argument value (@ulseq). The upper bits are derived from a base
value (@rb_next_seq) in a way that assumes @ulseq represents a
64bit number that is less than or equal to @rb_next_seq.
Until now this mapping has been correct for all call sites. However,
in a follow-up commit, values of @ulseq will be passed in that are
higher than the base value. This requires a change to how the 32bit
value is mapped to a 64bit sequence number.
Rather than mapping @ulseq such that the base value is the end of a
32bit block, map @ulseq such that the base value is in the middle of
a 32bit block. This allows supporting 31 bits before and after the
base value, which is deemed acceptable for the console sequence
number during runtime.
Here is an example to illustrate the previous and new mappings.
For a base value (@rb_next_seq) of 2 2000 0000...
Before this change the range of possible return values was:
1 2000 0001 to 2 2000 0000
__ulseq_to_u64seq(1fff ffff) => 2 1fff ffff
__ulseq_to_u64seq(2000 0000) => 2 2000 0000
__ulseq_to_u64seq(2000 0001) => 1 2000 0001
__ulseq_to_u64seq(9fff ffff) => 1 9fff ffff
__ulseq_to_u64seq(a000 0000) => 1 a000 0000
__ulseq_to_u64seq(a000 0001) => 1 a000 0001
After this change the range of possible return values are:
1 a000 0001 to 2 a000 0000
__ulseq_to_u64seq(1fff ffff) => 2 1fff ffff
__ulseq_to_u64seq(2000 0000) => 2 2000 0000
__ulseq_to_u64seq(2000 0001) => 2 2000 0001
__ulseq_to_u64seq(9fff ffff) => 2 9fff ffff
__ulseq_to_u64seq(a000 0000) => 2 a000 0000
__ulseq_to_u64seq(a000 0001) => 1 a000 0001
[ john.ogness: Rewrite commit message. ]
Reported-by: Francesco Dolcini <[email protected]>
Reported-by: kernel test robot <[email protected]>
Signed-off-by: Sebastian Andrzej Siewior <[email protected]>
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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The macros __seq_to_nbcon_seq() and __nbcon_seq_to_seq() are
used to provide support for atomic handling of sequence numbers
on 32bit systems. Until now this was only used by nbcon.c,
which is why they were located in nbcon.c and include nbcon in
the name.
In a follow-up commit this functionality is also needed by
printk_ringbuffer. Rather than duplicating the functionality,
relocate the macros to printk_ringbuffer.h.
Also, since the macros will be no longer nbcon-specific, rename
them to __u64seq_to_ulseq() and __ulseq_to_u64seq().
This does not result in any functional change.
Signed-off-by: John Ogness <[email protected]>
Reviewed-by: Petr Mladek <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Petr Mladek <[email protected]>
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Clocksource pointers can be problematic to obtain for drivers which are not
clocksource drivers themselves. In particular, the RFC virtio_rtc driver
[1] would require a new helper function to obtain a pointer to the ARM
Generic Timer clocksource. The ptp_kvm driver also required a similar
workaround.
Address this by evaluating the clocksource ID, rather than the clocksource
pointer, of struct system_counterval_t. By this, setting the clocksource
pointer becomes unneeded, and get_device_system_crosststamp() callers will
no longer need to supply clocksource pointers.
All relevant clocksource drivers provide the ID, so this change is not
changing the behaviour.
[1] https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Peter Hilber <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
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Now that the driver core can properly handle constant struct bus_type,
move the clockevents_subsys variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.
Suggested-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Ricardo B. Marliere <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
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Now that the driver core can properly handle constant struct bus_type,
move the clocksource_subsys variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.
Suggested-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Ricardo B. Marliere <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Greg Kroah-Hartman <[email protected]>
Acked-by: John Stultz <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
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We can get EBADF from pidfd_getfd() if a task is currently exiting,
which might be confusing. Let's check PF_EXITING, and just report ESRCH
if so.
I chose PF_EXITING, because it is set in exit_signals(), which is called
before exit_files(). Since ->exit_status is mostly set after
exit_files() in exit_notify(), using that still leaves a window open for
the race.
Reviewed-by: Oleg Nesterov <[email protected]>
Signed-off-by: Tycho Andersen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Christian Brauner <[email protected]>
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copy_process() just needs to pass PIDFD_THREAD to __pidfd_prepare()
if clone_flags & CLONE_THREAD.
We can also add another CLONE_ flag (or perhaps reuse CLONE_DETACHED)
to enforce PIDFD_THREAD without CLONE_THREAD.
Originally-from: Tycho Andersen <[email protected]>
Signed-off-by: Oleg Nesterov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Tycho Andersen <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
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It was used by pidfd_poll() but now it has no callers.
If it finally finds a modular user we can revert this change, but note
that the comment above this helper and the changelog in 38fd525a4c61
("exit: Factor thread_group_exited out of pidfd_poll") are not accurate,
thread_group_exited() won't return true if all other threads have passed
exit_notify() and are zombies, it returns true only when all other threads
are completely gone. Not to mention that it can only work if the task
identified by @pid is a thread-group leader.
Signed-off-by: Oleg Nesterov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Tycho Andersen <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
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rather than wake_up_all(). This way do_notify_pidfd() won't wakeup the
POLLHUP-only waiters which wait for pid_task() == NULL.
TODO:
- as Christian pointed out, this asks for the new wake_up_all_poll()
helper, it can already have other users.
- we can probably discriminate the PIDFD_THREAD and non-PIDFD_THREAD
waiters, but this needs more work. See
https://lore.kernel.org/all/[email protected]/
Signed-off-by: Oleg Nesterov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Tycho Andersen <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>
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The hrtimers migration on CPU-down hotplug process has been moved
earlier, before the CPU actually goes to die. This leaves a small window
of opportunity to queue an hrtimer in a blind spot, leaving it ignored.
For example a practical case has been reported with RCU waking up a
SCHED_FIFO task right before the CPUHP_AP_IDLE_DEAD stage, queuing that
way a sched/rt timer to the local offline CPU.
Make sure such situations never go unnoticed and warn when that happens.
Fixes: 5c0930ccaad5 ("hrtimers: Push pending hrtimers away from outgoing CPU earlier")
Reported-by: Paul E. McKenney <[email protected]>
Signed-off-by: Frederic Weisbecker <[email protected]>
Signed-off-by: Paul E. McKenney <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Cc: [email protected]
Link: https://lore.kernel.org/r/[email protected]
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Allow transferring an imbalanced RCU lock state between subprog calls
during verification. This allows patterns where a subprog call returns
with an RCU lock held, or a subprog call releases an RCU lock held by
the caller. Currently, the verifier would end up complaining if the RCU
lock is not released when processing an exit from a subprog, which is
non-ideal if its execution is supposed to be enclosed in an RCU read
section of the caller.
Instead, simply only check whether we are processing exit for frame#0
and do not complain on an active RCU lock otherwise. We only need to
update the check when processing BPF_EXIT insn, as copy_verifier_state
is already set up to do the right thing.
Suggested-by: David Vernet <[email protected]>
Tested-by: Yafang Shao <[email protected]>
Acked-by: Yonghong Song <[email protected]>
Signed-off-by: Kumar Kartikeya Dwivedi <[email protected]>
Acked-by: David Vernet <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>
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Currently, calling any helpers, kfuncs, or subprogs except the graph
data structure (lists, rbtrees) API kfuncs while holding a bpf_spin_lock
is not allowed. One of the original motivations of this decision was to
force the BPF programmer's hand into keeping the bpf_spin_lock critical
section small, and to ensure the execution time of the program does not
increase due to lock waiting times. In addition to this, some of the
helpers and kfuncs may be unsafe to call while holding a bpf_spin_lock.
However, when it comes to subprog calls, atleast for static subprogs,
the verifier is able to explore their instructions during verification.
Therefore, it is similar in effect to having the same code inlined into
the critical section. Hence, not allowing static subprog calls in the
bpf_spin_lock critical section is mostly an annoyance that needs to be
worked around, without providing any tangible benefit.
Unlike static subprog calls, global subprog calls are not safe to permit
within the critical section, as the verifier does not explore them
during verification, therefore whether the same lock will be taken
again, or unlocked, cannot be ascertained.
Therefore, allow calling static subprogs within a bpf_spin_lock critical
section, and only reject it in case the subprog linkage is global.
Acked-by: Yonghong Song <[email protected]>
Acked-by: David Vernet <[email protected]>
Signed-off-by: Kumar Kartikeya Dwivedi <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>
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The for-6.8-fixes commit ae9cc8956944 ("Revert "workqueue: Override implicit
ordered attribute in workqueue_apply_unbound_cpumask()") also fixes build for
Signed-off-by: Tejun Heo <[email protected]>
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workqueue_apply_unbound_cpumask()"
This reverts commit ca10d851b9ad0338c19e8e3089e24d565ebfffd7.
The commit allowed workqueue_apply_unbound_cpumask() to clear __WQ_ORDERED
on now removed implicitly ordered workqueues. This was incorrect in that
system-wide config change shouldn't break ordering properties of all
workqueues. The reason why apply_workqueue_attrs() path was allowed to do so
was because it was targeting the specific workqueue - either the workqueue
had WQ_SYSFS set or the workqueue user specifically tried to change
max_active, both of which indicate that the workqueue doesn't need to be
ordered.
The implicitly ordered workqueue promotion was removed by the previous
commit 3bc1e711c26b ("workqueue: Don't implicitly make UNBOUND workqueues w/
@max_active==1 ordered"). However, it didn't update this path and broke
build. Let's revert the commit which was incorrect in the first place which
also fixes build.
Signed-off-by: Tejun Heo <[email protected]>
Fixes: 3bc1e711c26b ("workqueue: Don't implicitly make UNBOUND workqueues w/ @max_active==1 ordered")
Fixes: ca10d851b9ad ("workqueue: Override implicit ordered attribute in workqueue_apply_unbound_cpumask()")
Cc: [email protected] # v6.6+
Signed-off-by: Tejun Heo <[email protected]>
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5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered")
automoatically promoted UNBOUND workqueues w/ @max_active==1 to ordered
workqueues because UNBOUND workqueues w/ @max_active==1 used to be the way
to create ordered workqueues and the new NUMA support broke it. These
problems can be subtle and the fact that they can only trigger on NUMA
machines made them even more difficult to debug.
However, overloading the UNBOUND allocation interface this way creates other
issues. It's difficult to tell whether a given workqueue actually needs to
be ordered and users that legitimately want a min concurrency level wq
unexpectedly gets an ordered one instead. With planned UNBOUND workqueue
udpates to improve execution locality and more prevalence of chiplet designs
which can benefit from such improvements, this isn't a state we wanna be in
forever.
There aren't that many UNBOUND w/ @max_active==1 users in the tree and the
preceding patches audited all and converted them to
alloc_ordered_workqueue() as appropriate. This patch removes the implicit
promotion of UNBOUND w/ @max_active==1 workqueues to ordered ones.
v2: v1 patch incorrectly dropped !list_empty(&wq->pwqs) condition in
apply_workqueue_attrs_locked() which spuriously triggers WARNING and
fails workqueue creation. Fix it.
Signed-off-by: Tejun Heo <[email protected]>
Reported-by: kernel test robot <[email protected]>
Link: https://lore.kernel.org/oe-lkp/[email protected]
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The only generic interface to execute asynchronously in the BH context is
tasklet; however, it's marked deprecated and has some design flaws. To
replace tasklets, BH workqueue support was recently added. A BH workqueue
behaves similarly to regular workqueues except that the queued work items
are executed in the BH context.
This patch converts backtracetest from tasklet to BH workqueue.
- Replace "irq" with "bh" in names and message to better reflect what's
happening.
- Replace completion usage with a flush_work() call.
Signed-off-by: Tejun Heo <[email protected]>
Cc: Arjan van de Ven <[email protected]>
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The "i" here is always equal to "btf_type_vlen(t)" since
the "for_each_member()" loop never breaks.
Signed-off-by: Kui-Feng Lee <[email protected]>
Acked-by: Yonghong Song <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin KaFai Lau <[email protected]>
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Skip updating workqueues with __WQ_DESTROYING bit set when updating
global unbound cpumask to avoid unnecessary work and other complications.
Signed-off-by: Waiman Long <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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There should be three, fix it.
Signed-off-by: Wang Jinchao <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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This reverts commit d412ace11144aa2bf692c7cf9778351efc15c827. This leads to
build failures as it depends on a driver-core commit 32f78abe59c7 ("driver
core: bus: constantify subsys_register() calls"). Let's drop it from wq tree
and route it through driver-core tree.
Signed-off-by: Tejun Heo <[email protected]>
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
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Mark the task as having a cached timestamp when set assign it, so we
can efficiently check if it needs updating post being scheduled back in.
This covers both the actual schedule out case, which would've flushed
the plug, and the preemption case which doesn't touch the plugged
requests (for many reasons, one of them being then we'd need to have
preemption disabled around plug state manipulation).
Reviewed-by: Johannes Thumshirn <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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Extend the support for LZ4 compression to be used with hibernation.
The main idea is that different compression algorithms
have different characteristics and hibernation may benefit when it uses
any of these algorithms: a default algorithm, having higher
compression rate but is slower(compression/decompression) and a
secondary algorithm, that is faster(compression/decompression) but has
lower compression rate.
LZ4 algorithm has better decompression speeds over LZO. This reduces
the hibernation image restore time.
As per test results:
LZO LZ4
Size before Compression(bytes) 682696704 682393600
Size after Compression(bytes) 146502402 155993547
Decompression Rate 335.02 MB/s 501.05 MB/s
Restore time 4.4s 3.8s
LZO is the default compression algorithm used for hibernation. Enable
CONFIG_HIBERNATION_COMP_LZ4 to set the default compressor as LZ4.
Signed-off-by: Nikhil V <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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Currently for hibernation, LZO is the only compression algorithm
available and uses the existing LZO library calls. However, there
is no flexibility to switch to other algorithms which provides better
results. The main idea is that different compression algorithms have
different characteristics and hibernation may benefit when it uses
alternate algorithms.
By moving to crypto based APIs, it lays a foundation to use other
compression algorithms for hibernation. There are no functional changes
introduced by this approach.
Signed-off-by: Nikhil V <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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Renaming lzo* to generic names, except for lzo_xxx() APIs. This is
used in the next patch where we move to crypto based APIs for
compression. There are no functional changes introduced by this
approach.
Signed-off-by: Nikhil V <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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Because dpm_save_failed_dev() may be called simultaneously by multiple
failing device PM functions, the state of the suspend_stats fields
updated by it may become inconsistent.
Prevent that from happening by using a lock in dpm_save_failed_dev().
Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Stanislaw Gruszka <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
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It is not necessary to define struct suspend_stats in a header file and the
suspend_stats variable in the core device system-wide PM code. They both
can be defined in kernel/power/main.c, next to the sysfs and debugfs code
accessing suspend_stats, which can be static.
Modify the code in question in accordance with the above observation and
replace the static inline functions manipulating suspend_stats with
regular ones defined in kernel/power/main.c.
While at it, move the enum suspend_stat_step to the end of suspend.h which
is a more suitable place for it.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
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