mirror of https://github.com/torvalds/linux.git
3417 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Linus Torvalds
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35ce8ae9ae |
Merge branch 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull signal/exit/ptrace updates from Eric Biederman:
"This set of changes deletes some dead code, makes a lot of cleanups
which hopefully make the code easier to follow, and fixes bugs found
along the way.
The end-game which I have not yet reached yet is for fatal signals
that generate coredumps to be short-circuit deliverable from
complete_signal, for force_siginfo_to_task not to require changing
userspace configured signal delivery state, and for the ptrace stops
to always happen in locations where we can guarantee on all
architectures that the all of the registers are saved and available on
the stack.
Removal of profile_task_ext, profile_munmap, and profile_handoff_task
are the big successes for dead code removal this round.
A bunch of small bug fixes are included, as most of the issues
reported were small enough that they would not affect bisection so I
simply added the fixes and did not fold the fixes into the changes
they were fixing.
There was a bug that broke coredumps piped to systemd-coredump. I
dropped the change that caused that bug and replaced it entirely with
something much more restrained. Unfortunately that required some
rebasing.
Some successes after this set of changes: There are few enough calls
to do_exit to audit in a reasonable amount of time. The lifetime of
struct kthread now matches the lifetime of struct task, and the
pointer to struct kthread is no longer stored in set_child_tid. The
flag SIGNAL_GROUP_COREDUMP is removed. The field group_exit_task is
removed. Issues where task->exit_code was examined with
signal->group_exit_code should been examined were fixed.
There are several loosely related changes included because I am
cleaning up and if I don't include them they will probably get lost.
The original postings of these changes can be found at:
https://lkml.kernel.org/r/87a6ha4zsd.fsf@email.froward.int.ebiederm.org
https://lkml.kernel.org/r/87bl1kunjj.fsf@email.froward.int.ebiederm.org
https://lkml.kernel.org/r/87r19opkx1.fsf_-_@email.froward.int.ebiederm.org
I trimmed back the last set of changes to only the obviously correct
once. Simply because there was less time for review than I had hoped"
* 'signal-for-v5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (44 commits)
ptrace/m68k: Stop open coding ptrace_report_syscall
ptrace: Remove unused regs argument from ptrace_report_syscall
ptrace: Remove second setting of PT_SEIZED in ptrace_attach
taskstats: Cleanup the use of task->exit_code
exit: Use the correct exit_code in /proc/<pid>/stat
exit: Fix the exit_code for wait_task_zombie
exit: Coredumps reach do_group_exit
exit: Remove profile_handoff_task
exit: Remove profile_task_exit & profile_munmap
signal: clean up kernel-doc comments
signal: Remove the helper signal_group_exit
signal: Rename group_exit_task group_exec_task
coredump: Stop setting signal->group_exit_task
signal: Remove SIGNAL_GROUP_COREDUMP
signal: During coredumps set SIGNAL_GROUP_EXIT in zap_process
signal: Make coredump handling explicit in complete_signal
signal: Have prepare_signal detect coredumps using signal->core_state
signal: Have the oom killer detect coredumps using signal->core_state
exit: Move force_uaccess back into do_exit
exit: Guarantee make_task_dead leaks the tsk when calling do_task_exit
...
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Linus Torvalds
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daadb3bd0e |
Peter Zijlstra says:
"Lots of cleanups and preparation; highlights:
- futex: Cleanup and remove runtime futex_cmpxchg detection
- rtmutex: Some fixes for the PREEMPT_RT locking infrastructure
- kcsan: Share owner_on_cpu() between mutex,rtmutex and rwsem and
annotate the racy owner->on_cpu access *once*.
- atomic64: Dead-Code-Elemination"
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Merge tag 'locking_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Borislav Petkov:
"Lots of cleanups and preparation. Highlights:
- futex: Cleanup and remove runtime futex_cmpxchg detection
- rtmutex: Some fixes for the PREEMPT_RT locking infrastructure
- kcsan: Share owner_on_cpu() between mutex,rtmutex and rwsem and
annotate the racy owner->on_cpu access *once*.
- atomic64: Dead-Code-Elemination"
[ Description above by Peter Zijlstra ]
* tag 'locking_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/atomic: atomic64: Remove unusable atomic ops
futex: Fix additional regressions
locking: Allow to include asm/spinlock_types.h from linux/spinlock_types_raw.h
x86/mm: Include spinlock_t definition in pgtable.
locking: Mark racy reads of owner->on_cpu
locking: Make owner_on_cpu() into <linux/sched.h>
lockdep/selftests: Adapt ww-tests for PREEMPT_RT
lockdep/selftests: Skip the softirq related tests on PREEMPT_RT
lockdep/selftests: Unbalanced migrate_disable() & rcu_read_lock().
lockdep/selftests: Avoid using local_lock_{acquire|release}().
lockdep: Remove softirq accounting on PREEMPT_RT.
locking/rtmutex: Add rt_mutex_lock_nest_lock() and rt_mutex_lock_killable().
locking/rtmutex: Squash self-deadlock check for ww_rt_mutex.
locking: Remove rt_rwlock_is_contended().
sched: Trigger warning if ->migration_disabled counter underflows.
futex: Fix sparc32/m68k/nds32 build regression
futex: Remove futex_cmpxchg detection
futex: Ensure futex_atomic_cmpxchg_inatomic() is present
kernel/locking: Use a pointer in ww_mutex_trylock().
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Linus Torvalds
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6ae71436cd |
Peter Zijlstra says:
"Mostly minor things this time; some highlights:
- core-sched: Add 'Forced Idle' accounting; this allows to track how
much CPU time is 'lost' due to core scheduling constraints.
- psi: Fix for MEM_FULL; a task running reclaim would be counted as a
runnable task and prevent MEM_FULL from being reported.
- cpuacct: Long standing fixes for some cgroup accounting issues.
- rt: Bandwidth timer could, under unusual circumstances, be failed to
armed, leading to indefinite throttling."
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Merge tag 'sched_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Borislav Petkov:
"Mostly minor things this time; some highlights:
- core-sched: Add 'Forced Idle' accounting; this allows to track how
much CPU time is 'lost' due to core scheduling constraints.
- psi: Fix for MEM_FULL; a task running reclaim would be counted as a
runnable task and prevent MEM_FULL from being reported.
- cpuacct: Long standing fixes for some cgroup accounting issues.
- rt: Bandwidth timer could, under unusual circumstances, be failed
to armed, leading to indefinite throttling."
[ Description above by Peter Zijlstra ]
* tag 'sched_core_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Replace CFS internal cpu_util() with cpu_util_cfs()
sched/fair: Cleanup task_util and capacity type
sched/rt: Try to restart rt period timer when rt runtime exceeded
sched/fair: Document the slow path and fast path in select_task_rq_fair
sched/fair: Fix per-CPU kthread and wakee stacking for asym CPU capacity
sched/fair: Fix detection of per-CPU kthreads waking a task
sched/cpuacct: Make user/system times in cpuacct.stat more precise
sched/cpuacct: Fix user/system in shown cpuacct.usage*
cpuacct: Convert BUG_ON() to WARN_ON_ONCE()
cputime, cpuacct: Include guest time in user time in cpuacct.stat
psi: Fix PSI_MEM_FULL state when tasks are in memstall and doing reclaim
sched/core: Forced idle accounting
psi: Add a missing SPDX license header
psi: Remove repeated verbose comment
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Linus Torvalds
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1be5bdf8cd |
KCSAN updates for v5.17
This series provides KCSAN fixes and also the ability to take memory barriers into account for weakly-ordered systems. This last can increase the probability of detecting certain types of data races. -----BEGIN PGP SIGNATURE----- iQJHBAABCgAxFiEEbK7UrM+RBIrCoViJnr8S83LZ+4wFAmHbuRwTHHBhdWxtY2tA a2VybmVsLm9yZwAKCRCevxLzctn7jKDPEACWuzYnd/u/02AHyRd3PIF3Px9uFKlK TFwaXX95oYSFCXcrmO42YtDUlZm4QcbwNb85KMCu1DvckRtIsNw0rkBU7BGyqv3Z ZoJEfMNpmC0x9+IFBOeseBHySPVT0x7GmYus05MSh0OLfkbCfyImmxRzgoKJGL+A ADF9EQb4z2feWjmVEoN8uRaarCAD4f77rSXiX6oTCNDuKrHarqMld/TmoXFrJbu2 QtfwHeyvraKBnZdUoYfVbGVenyKb1vMv4bUlvrOcuJEgIi/J/th4FupR3XCGYulI aWJTl2TQTGnMoE8VnFHgI27I841w3k5PVL+Y1hr/S4uN1/rIoQQuBzCtlnFeCksa BiBXsHIchN8N0Dwh8zD8NMd2uxV4t3fmpxXTDAwaOm7vs5hA8AJ0XNu6Sz94Lyjv wk2CxX41WWUNJVo3gh6SrS4mL6lC8+VvHF1hbIap++jrevj58gj1jAR1fdx4ANlT e2qA00EeoMngEogDNZH42/Fxs3H9zxrBta2ZbkPkwzIqTHH+4pIQDCy2xO3T3oxc twdGPYpjYdkf79EGsG4I4R/VA/IfcS09VIWTce8xSDeSnqkgFhcG37r1orJe8hTB tH+ODkNOsz5HaEoa8OoAL4ko2l0fL99p2AtMPpuQfHjRj7aorF+dJIrqCizASxwx 37PjQgOmHeDHgQ== =Q5fg -----END PGP SIGNATURE----- Merge tag 'kcsan.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu Pull KCSAN updates from Paul McKenney: "This provides KCSAN fixes and also the ability to take memory barriers into account for weakly-ordered systems. This last can increase the probability of detecting certain types of data races" * tag 'kcsan.2022.01.09a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (29 commits) kcsan: Only test clear_bit_unlock_is_negative_byte if arch defines it kcsan: Avoid nested contexts reading inconsistent reorder_access kcsan: Turn barrier instrumentation into macros kcsan: Make barrier tests compatible with lockdep kcsan: Support WEAK_MEMORY with Clang where no objtool support exists compiler_attributes.h: Add __disable_sanitizer_instrumentation objtool, kcsan: Remove memory barrier instrumentation from noinstr objtool, kcsan: Add memory barrier instrumentation to whitelist sched, kcsan: Enable memory barrier instrumentation mm, kcsan: Enable barrier instrumentation x86/qspinlock, kcsan: Instrument barrier of pv_queued_spin_unlock() x86/barriers, kcsan: Use generic instrumentation for non-smp barriers asm-generic/bitops, kcsan: Add instrumentation for barriers locking/atomics, kcsan: Add instrumentation for barriers locking/barriers, kcsan: Support generic instrumentation locking/barriers, kcsan: Add instrumentation for barriers kcsan: selftest: Add test case to check memory barrier instrumentation kcsan: Ignore GCC 11+ warnings about TSan runtime support kcsan: test: Add test cases for memory barrier instrumentation kcsan: test: Match reordered or normal accesses ... |
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Linus Torvalds
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48a60bdb2b |
- Add a set of thread_info.flags accessors which snapshot it before
accesing it in order to prevent any potential data races, and convert all users to those new accessors -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEzv7L6UO9uDPlPSfHEsHwGGHeVUoFAmHcgFoACgkQEsHwGGHe VUqXeRAAvcNEfFw6BvXeGfFTxKmOrsRtu2WCkAkjvamyhXMCrjBqqHlygLJFCH5i 2mc6HBohzo4vBFcgi3R5tVkGazqlthY1KUM9Jpk7rUuUzi0phTH7n/MafZOm9Es/ BHYcAAyT/NwZRbCN0geccIzBtbc4xr8kxtec7vkRfGDx8B9/uFN86xm7cKAaL62G UDs0IquDPKEns3A7uKNuvKztILtuZWD1WcSkbOULJzXgLkb+cYKO1Lm9JK9rx8Ds 8tjezrJgOYGLQyyv0i3pWelm3jCZOKUChPslft0opvVUbrNd8piehvOm9CWopHcB QsYOWchnULTE9o4ZAs/1PkxC0LlFEWZH8bOLxBMTDVEY+xvmDuj1PdBUpncgJbOh dunHzsvaWproBSYUXA9nKhZWTVGl+CM8Ks7jXjl3IPynLd6cpYZ/5gyBVWEX7q3e 8htG95NzdPPo7doxMiNSKGSmSm0Np1TJ/i89vsYeGfefsvsq53Fyjhu7dIuTWHmU 2YUe6qHs6dF9x1bkHAAZz6T9Hs4BoGQBcXUnooT9JbzVdv2RfTPsrawdu8dOnzV1 RhwCFdFcll0AIEl0T9fCYzUI/Ga8ZS0roXs5NZ4wl0lwr0BGFwiU8WC1FUdGsZo9 0duaa0Tpv0OWt6rIMMB/E9QsqCDsQ4CMHuQpVVw+GOO5ux9kMms= =v6Xn -----END PGP SIGNATURE----- Merge tag 'core_entry_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull thread_info flag accessor helper updates from Borislav Petkov: "Add a set of thread_info.flags accessors which snapshot it before accesing it in order to prevent any potential data races, and convert all users to those new accessors" * tag 'core_entry_for_v5.17_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: powerpc: Snapshot thread flags powerpc: Avoid discarding flags in system_call_exception() openrisc: Snapshot thread flags microblaze: Snapshot thread flags arm64: Snapshot thread flags ARM: Snapshot thread flags alpha: Snapshot thread flags sched: Snapshot thread flags entry: Snapshot thread flags x86: Snapshot thread flags thread_info: Add helpers to snapshot thread flags |
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Eric W. Biederman
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e32cf5dfbe |
kthread: Generalize pf_io_worker so it can point to struct kthread
The point of using set_child_tid to hold the kthread pointer was that it already did what is necessary. There are now restrictions on when set_child_tid can be initialized and when set_child_tid can be used in schedule_tail. Which indicates that continuing to use set_child_tid to hold the kthread pointer is a bad idea. Instead of continuing to use the set_child_tid field of task_struct generalize the pf_io_worker field of task_struct and use it to hold the kthread pointer. Rename pf_io_worker (which is a void * pointer) to worker_private so it can be used to store kthreads struct kthread pointer. Update the kthread code to store the kthread pointer in the worker_private field. Remove the places where set_child_tid had to be dealt with carefully because kthreads also used it. Link: https://lkml.kernel.org/r/CAHk-=wgtFAA9SbVYg0gR1tqPMC17-NYcs0GQkaYg1bGhh1uJQQ@mail.gmail.com Link: https://lkml.kernel.org/r/87a6grvqy8.fsf_-_@email.froward.int.ebiederm.org Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
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Eric W. Biederman
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00580f03af |
kthread: Never put_user the set_child_tid address
Kernel threads abuse set_child_tid. Historically that has been fine as set_child_tid was initialized after the kernel thread had been forked. Unfortunately storing struct kthread in set_child_tid after the thread is running makes struct kthread being unusable for storing result codes of the thread. When set_child_tid is set to struct kthread during fork that results in schedule_tail writing the thread id to the beggining of struct kthread (if put_user does not realize it is a kernel address). Solve this by skipping the put_user for all kthreads. Reported-by: Nathan Chancellor <nathan@kernel.org> Link: https://lkml.kernel.org/r/YcNsG0Lp94V13whH@archlinux-ax161 Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
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Eric W. Biederman
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dd621ee0cf |
kthread: Warn about failed allocations for the init kthread
Failed allocates are not expected when setting up the initial task and
it is not really possible to handle them either. So I added a warning
to report if such an allocation failure ever happens.
Correct the sense of the warning so it warns when an allocation failure
happens not when the allocation succeeded. Oops.
Reported-by: kernel test robot <oliver.sang@intel.com>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Link: https://lkml.kernel.org/r/20211221231611.785b74cf@canb.auug.org.au
Link: https://lkml.kernel.org/r/CA+G9fYvLaR5CF777CKeWTO+qJFTN6vAvm95gtzN+7fw3Wi5hkA@mail.gmail.com
Link: https://lkml.kernel.org/r/20211216102956.GC10708@xsang-OptiPlex-9020
Fixes:
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Eric W. Biederman
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40966e316f |
kthread: Ensure struct kthread is present for all kthreads
Today the rules are a bit iffy and arbitrary about which kernel threads have struct kthread present. Both idle threads and thread started with create_kthread want struct kthread present so that is effectively all kernel threads. Make the rule that if PF_KTHREAD and the task is running then struct kthread is present. This will allow the kernel thread code to using tsk->exit_code with different semantics from ordinary processes. To make ensure that struct kthread is present for all kernel threads move it's allocation into copy_process. Add a deallocation of struct kthread in exec for processes that were kernel threads. Move the allocation of struct kthread for the initial thread earlier so that it is not repeated for each additional idle thread. Move the initialization of struct kthread into set_kthread_struct so that the structure is always and reliably initailized. Clear set_child_tid in free_kthread_struct to ensure the kthread struct is reliably freed during exec. The function free_kthread_struct does not need to clear vfork_done during exec as exec_mm_release called from exec_mmap has already cleared vfork_done. Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> |
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Ingo Molnar
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6773cc31a9 |
Linux 5.16-rc5
-----BEGIN PGP SIGNATURE----- iQFSBAABCAA8FiEEq68RxlopcLEwq+PEeb4+QwBBGIYFAmG2fU0eHHRvcnZhbGRz QGxpbnV4LWZvdW5kYXRpb24ub3JnAAoJEHm+PkMAQRiGC7EH/3R7Rt+OD8Wn8Ss3 w8V+dBxVwa2u2oMTyUHPxaeOXZ7bi38XlUdLFPOK/76bGwO0a5TmYZqsWdRbGyT0 HfcYjHsQ0lbJXk/nh2oM47oJxJXVpThIHXJEk0FZ0Y5t+DYjIYlNHzqZymUyhLem St74zgWcyT+MXuqY34vB827FJDUnOxhhhi85tObeunaSPAomy9aiYidSC1ARREnz iz2VUntP/QnRnKVvL2nUZNzcz1xL5vfCRSKsRGRSv3qW1Y/1M71ylt6JVmSftWq+ VmMdFxFhdrb1OK/1ct/930Un/UP2NG9EJsWxote2XYlnVSZHzDqH7lUhbqgdCcLz 1m2tVNY= =7wRd -----END PGP SIGNATURE----- Merge tag 'v5.16-rc5' into locking/core, to pick up fixes Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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Dietmar Eggemann
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82762d2af3 |
sched/fair: Replace CFS internal cpu_util() with cpu_util_cfs()
cpu_util_cfs() was created by commit |
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Marco Elver
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6f3f0c98b5 |
sched, kcsan: Enable memory barrier instrumentation
There's no fundamental reason to disable KCSAN for scheduler code, except for excessive noise and performance concerns (instrumenting scheduler code is usually a good way to stress test KCSAN itself). However, several core sched functions imply memory barriers that are invisible to KCSAN without instrumentation, but are required to avoid false positives. Therefore, unconditionally enable instrumentation of memory barriers in scheduler code. Also update the comment to reflect this and be a bit more brief. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> |
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Eric Biggers
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42288cb44c |
wait: add wake_up_pollfree()
Several ->poll() implementations are special in that they use a waitqueue whose lifetime is the current task, rather than the struct file as is normally the case. This is okay for blocking polls, since a blocking poll occurs within one task; however, non-blocking polls require another solution. This solution is for the queue to be cleared before it is freed, using 'wake_up_poll(wq, EPOLLHUP | POLLFREE);'. However, that has a bug: wake_up_poll() calls __wake_up() with nr_exclusive=1. Therefore, if there are multiple "exclusive" waiters, and the wakeup function for the first one returns a positive value, only that one will be called. That's *not* what's needed for POLLFREE; POLLFREE is special in that it really needs to wake up everyone. Considering the three non-blocking poll systems: - io_uring poll doesn't handle POLLFREE at all, so it is broken anyway. - aio poll is unaffected, since it doesn't support exclusive waits. However, that's fragile, as someone could add this feature later. - epoll doesn't appear to be broken by this, since its wakeup function returns 0 when it sees POLLFREE. But this is fragile. Although there is a workaround (see epoll), it's better to define a function which always sends POLLFREE to all waiters. Add such a function. Also make it verify that the queue really becomes empty after all waiters have been woken up. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20211209010455.42744-2-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> |
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Vincent Donnefort
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ef8df9798d |
sched/fair: Cleanup task_util and capacity type
task_util and capacity are comparable unsigned long values. There is no need for an intermidiate implicit signed cast. Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211207095755.859972-1-vincent.donnefort@arm.com |
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Li Hua
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9b58e976b3 |
sched/rt: Try to restart rt period timer when rt runtime exceeded
When rt_runtime is modified from -1 to a valid control value, it may
cause the task to be throttled all the time. Operations like the following
will trigger the bug. E.g:
1. echo -1 > /proc/sys/kernel/sched_rt_runtime_us
2. Run a FIFO task named A that executes while(1)
3. echo 950000 > /proc/sys/kernel/sched_rt_runtime_us
When rt_runtime is -1, The rt period timer will not be activated when task
A enqueued. And then the task will be throttled after setting rt_runtime to
950,000. The task will always be throttled because the rt period timer is
not activated.
Fixes:
|
|
Barry Song
|
2917406c35 |
sched/fair: Document the slow path and fast path in select_task_rq_fair
All People I know including myself took a long time to figure out that typical wakeup will always go to fast path and never go to slow path except WF_FORK and WF_EXEC. Vincent reminded me once in a linaro meeting and made me understand slow path won't happen for WF_TTWU. But my other friends repeatedly wasted a lot of time on testing this path like me before I reminded them. So obviously the code needs some document. Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211016111109.5559-1-21cnbao@gmail.com |
|
Sebastian Andrzej Siewior
|
9d0df37797 |
sched: Trigger warning if ->migration_disabled counter underflows.
If migrate_enable() is used more often than its counter part then it remains undetected and rq::nr_pinned will underflow, too. Add a warning if migrate_enable() is attempted if without a matching a migrate_disable(). Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20211129174654.668506-2-bigeasy@linutronix.de |
|
|
Vincent Donnefort
|
014ba44e81 |
sched/fair: Fix per-CPU kthread and wakee stacking for asym CPU capacity
select_idle_sibling() has a special case for tasks woken up by a per-CPU
kthread where the selected CPU is the previous one. For asymmetric CPU
capacity systems, the assumption was that the wakee couldn't have a
bigger utilization during task placement than it used to have during the
last activation. That was not considering uclamp.min which can completely
change between two task activations and as a consequence mandates the
fitness criterion asym_fits_capacity(), even for the exit path described
above.
Fixes:
|
|
|
Vincent Donnefort
|
8b4e74ccb5 |
sched/fair: Fix detection of per-CPU kthreads waking a task
select_idle_sibling() has a special case for tasks woken up by a per-CPU
kthread, where the selected CPU is the previous one. However, the current
condition for this exit path is incomplete. A task can wake up from an
interrupt context (e.g. hrtimer), while a per-CPU kthread is running. A
such scenario would spuriously trigger the special case described above.
Also, a recent change made the idle task like a regular per-CPU kthread,
hence making that situation more likely to happen
(is_per_cpu_kthread(swapper) being true now).
Checking for task context makes sure select_idle_sibling() will not
interpret a wake up from any other context as a wake up by a per-CPU
kthread.
Fixes:
|
|
Qais Yousef
|
315c4f8848 |
sched/uclamp: Fix rq->uclamp_max not set on first enqueue
Commit |
|
Andrew Halaney
|
9ed20bafc8 |
preempt/dynamic: Fix setup_preempt_mode() return value
__setup() callbacks expect 1 for success and 0 for failure. Correct the
usage here to reflect that.
Fixes:
|
|
Frederic Weisbecker
|
e7f2be115f |
sched/cputime: Fix getrusage(RUSAGE_THREAD) with nohz_full
getrusage(RUSAGE_THREAD) with nohz_full may return shorter utime/stime than the actual time. task_cputime_adjusted() snapshots utime and stime and then adjust their sum to match the scheduler maintained cputime.sum_exec_runtime. Unfortunately in nohz_full, sum_exec_runtime is only updated once per second in the worst case, causing a discrepancy against utime and stime that can be updated anytime by the reader using vtime. To fix this situation, perform an update of cputime.sum_exec_runtime when the cputime snapshot reports the task as actually running while the tick is disabled. The related overhead is then contained within the relevant situations. Reported-by: Hasegawa Hitomi <hasegawa-hitomi@fujitsu.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Hasegawa Hitomi <hasegawa-hitomi@fujitsu.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Masayoshi Mizuma <m.mizuma@jp.fujitsu.com> Acked-by: Phil Auld <pauld@redhat.com> Link: https://lore.kernel.org/r/20211026141055.57358-3-frederic@kernel.org |
|
Mark Rutland
|
0569b24513 |
sched: Snapshot thread flags
Some thread flags can be set remotely, and so even when IRQs are disabled, the flags can change under our feet. Generally this is unlikely to cause a problem in practice, but it is somewhat unsound, and KCSAN will legitimately warn that there is a data race. To avoid such issues, a snapshot of the flags has to be taken prior to using them. Some places already use READ_ONCE() for that, others do not. Convert them all to the new flag accessor helpers. The READ_ONCE(ti->flags) .. cmpxchg(ti->flags) loop in set_nr_if_polling() is left as-is for clarity. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Paul E. McKenney <paulmck@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Link: https://lore.kernel.org/r/20211129130653.2037928-4-mark.rutland@arm.com |
|
|
Mark Rutland
|
dce1ca0525 |
sched/scs: Reset task stack state in bringup_cpu()
To hot unplug a CPU, the idle task on that CPU calls a few layers of C code before finally leaving the kernel. When KASAN is in use, poisoned shadow is left around for each of the active stack frames, and when shadow call stacks are in use. When shadow call stacks (SCS) are in use the task's saved SCS SP is left pointing at an arbitrary point within the task's shadow call stack. When a CPU is offlined than onlined back into the kernel, this stale state can adversely affect execution. Stale KASAN shadow can alias new stackframes and result in bogus KASAN warnings. A stale SCS SP is effectively a memory leak, and prevents a portion of the shadow call stack being used. Across a number of hotplug cycles the idle task's entire shadow call stack can become unusable. We previously fixed the KASAN issue in commit: |
|
Andrey Ryabinin
|
8c92606ab8 |
sched/cpuacct: Make user/system times in cpuacct.stat more precise
cpuacct.stat shows user time based on raw random precision tick based counters. Use cputime_addjust() to scale these values against the total runtime accounted by the scheduler, like we already do for user/system times in /proc/<pid>/stat. Signed-off-by: Andrey Ryabinin <arbn@yandex-team.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20211115164607.23784-4-arbn@yandex-team.com |
|
|
Andrey Ryabinin
|
dd02d4234c |
sched/cpuacct: Fix user/system in shown cpuacct.usage*
cpuacct has 2 different ways of accounting and showing user
and system times.
The first one uses cpuacct_account_field() to account times
and cpuacct.stat file to expose them. And this one seems to work ok.
The second one is uses cpuacct_charge() function for accounting and
set of cpuacct.usage* files to show times. Despite some attempts to
fix it in the past it still doesn't work. Sometimes while running KVM
guest the cpuacct_charge() accounts most of the guest time as
system time. This doesn't match with user&system times shown in
cpuacct.stat or proc/<pid>/stat.
Demonstration:
# git clone https://github.com/aryabinin/kvmsample
# make
# mkdir /sys/fs/cgroup/cpuacct/test
# echo $$ > /sys/fs/cgroup/cpuacct/test/tasks
# ./kvmsample &
# for i in {1..5}; do cat /sys/fs/cgroup/cpuacct/test/cpuacct.usage_sys; sleep 1; done
1976535645
2979839428
3979832704
4983603153
5983604157
Use cpustats accounted in cpuacct_account_field() as the source
of user/sys times for cpuacct.usage* files. Make cpuacct_charge()
to account only summary execution time.
Fixes:
|
|
|
Andrey Ryabinin
|
c7ccbf4b61 |
cpuacct: Convert BUG_ON() to WARN_ON_ONCE()
Replace fatal BUG_ON() with more safe WARN_ON_ONCE() in cpuacct_cpuusage_read(). Signed-off-by: Andrey Ryabinin <arbn@yandex-team.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20211115164607.23784-2-arbn@yandex-team.com |
|
|
Andrey Ryabinin
|
9731698ecb |
cputime, cpuacct: Include guest time in user time in cpuacct.stat
cpuacct.stat in no-root cgroups shows user time without guest time
included int it. This doesn't match with user time shown in root
cpuacct.stat and /proc/<pid>/stat. This also affects cgroup2's cpu.stat
in the same way.
Make account_guest_time() to add user time to cgroup's cpustat to
fix this.
Fixes:
|
|
Brian Chen
|
cb0e52b774 |
psi: Fix PSI_MEM_FULL state when tasks are in memstall and doing reclaim
We've noticed cases where tasks in a cgroup are stalled on memory but
there is little memory FULL pressure since tasks stay on the runqueue
in reclaim.
A simple example involves a single threaded program that keeps leaking
and touching large amounts of memory. It runs in a cgroup with swap
enabled, memory.high set at 10M and cpu.max ratio set at 5%. Though
there is significant CPU pressure and memory SOME, there is barely any
memory FULL since the task enters reclaim and stays on the runqueue.
However, this memory-bound task is effectively stalled on memory and
we expect memory FULL to match memory SOME in this scenario.
The code is confused about memstall && running, thinking there is a
stalled task and a productive task when there's only one task: a
reclaimer that's counted as both. To fix this, we redefine the
condition for PSI_MEM_FULL to check that all running tasks are in an
active memstall instead of checking that there are no running tasks.
case PSI_MEM_FULL:
- return unlikely(tasks[NR_MEMSTALL] && !tasks[NR_RUNNING]);
+ return unlikely(tasks[NR_MEMSTALL] &&
+ tasks[NR_RUNNING] == tasks[NR_MEMSTALL_RUNNING]);
This will capture reclaimers. It will also capture tasks that called
psi_memstall_enter() and are about to sleep, but this should be
negligible noise.
Signed-off-by: Brian Chen <brianchen118@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Link: https://lore.kernel.org/r/20211110213312.310243-1-brianchen118@gmail.com
|
|
Josh Don
|
4feee7d126 |
sched/core: Forced idle accounting
Adds accounting for "forced idle" time, which is time where a cookie'd task forces its SMT sibling to idle, despite the presence of runnable tasks. Forced idle time is one means to measure the cost of enabling core scheduling (ie. the capacity lost due to the need to force idle). Forced idle time is attributed to the thread responsible for causing the forced idle. A few details: - Forced idle time is displayed via /proc/PID/sched. It also requires that schedstats is enabled. - Forced idle is only accounted when a sibling hyperthread is held idle despite the presence of runnable tasks. No time is charged if a sibling is idle but has no runnable tasks. - Tasks with 0 cookie are never charged forced idle. - For SMT > 2, we scale the amount of forced idle charged based on the number of forced idle siblings. Additionally, we split the time up and evenly charge it to all running tasks, as each is equally responsible for the forced idle. Signed-off-by: Josh Don <joshdon@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211018203428.2025792-1-joshdon@google.com |
|
Liu Xinpeng
|
2fb75e1b64 |
psi: Add a missing SPDX license header
Add the missing SPDX license header to include/linux/psi.h include/linux/psi_types.h kernel/sched/psi.c Signed-off-by: Liu Xinpeng <liuxp11@chinatelecom.cn> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lore.kernel.org/r/1635133586-84611-2-git-send-email-liuxp11@chinatelecom.cn |
|
|
Liu Xinpeng
|
2d3791f116 |
psi: Remove repeated verbose comment
Comment in function psi_task_switch,there are two same lines. ... * runtime state, the cgroup that contains both tasks * runtime state, the cgroup that contains both tasks ... Signed-off-by: Liu Xinpeng <liuxp11@chinatelecom.cn> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Link: https://lore.kernel.org/r/1635133586-84611-1-git-send-email-liuxp11@chinatelecom.cn |
|
Valentin Schneider
|
a8b76910e4 |
preempt: Restore preemption model selection configs
Commit
|
|
Mathias Krause
|
b027789e5e |
sched/fair: Prevent dead task groups from regaining cfs_rq's
Kevin is reporting crashes which point to a use-after-free of a cfs_rq in update_blocked_averages(). Initial debugging revealed that we've live cfs_rq's (on_list=1) in an about to be kfree()'d task group in free_fair_sched_group(). However, it was unclear how that can happen. His kernel config happened to lead to a layout of struct sched_entity that put the 'my_q' member directly into the middle of the object which makes it incidentally overlap with SLUB's freelist pointer. That, in combination with SLAB_FREELIST_HARDENED's freelist pointer mangling, leads to a reliable access violation in form of a #GP which made the UAF fail fast. Michal seems to have run into the same issue[1]. He already correctly diagnosed that commit |
|
|
Vincent Donnefort
|
42dc938a59 |
sched/core: Mitigate race cpus_share_cache()/update_top_cache_domain()
Nothing protects the access to the per_cpu variable sd_llc_id. When testing
the same CPU (i.e. this_cpu == that_cpu), a race condition exists with
update_top_cache_domain(). One scenario being:
CPU1 CPU2
==================================================================
per_cpu(sd_llc_id, CPUX) => 0
partition_sched_domains_locked()
detach_destroy_domains()
cpus_share_cache(CPUX, CPUX) update_top_cache_domain(CPUX)
per_cpu(sd_llc_id, CPUX) => 0
per_cpu(sd_llc_id, CPUX) = CPUX
per_cpu(sd_llc_id, CPUX) => CPUX
return false
ttwu_queue_cond() wouldn't catch smp_processor_id() == cpu and the result
is a warning triggered from ttwu_queue_wakelist().
Avoid a such race in cpus_share_cache() by always returning true when
this_cpu == that_cpu.
Fixes:
|
|
|
Linus Torvalds
|
a41b74451b |
kernel.sys.v5.16
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Merge tag 'kernel.sys.v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull prctl updates from Christian Brauner:
"This contains the missing prctl uapi pieces for PR_SCHED_CORE.
In order to activate core scheduling the caller is expected to specify
the scope of the new core scheduling domain.
For example, passing 2 in the 4th argument of
prctl(PR_SCHED_CORE, PR_SCHED_CORE_CREATE, <pid>, 2, 0);
would indicate that the new core scheduling domain encompasses all
tasks in the process group of <pid>. Specifying 0 would only create a
core scheduling domain for the thread identified by <pid> and 2 would
encompass the whole thread-group of <pid>.
Note, the values 0, 1, and 2 correspond to PIDTYPE_PID, PIDTYPE_TGID,
and PIDTYPE_PGID. A first version tried to expose those values
directly to which I objected because:
- PIDTYPE_* is an enum that is kernel internal which we should not
expose to userspace directly.
- PIDTYPE_* indicates what a given struct pid is used for it doesn't
express a scope.
But what the 4th argument of PR_SCHED_CORE prctl() expresses is the
scope of the operation, i.e. the scope of the core scheduling domain
at creation time. So Eugene's patch now simply introduces three new
defines PR_SCHED_CORE_SCOPE_THREAD, PR_SCHED_CORE_SCOPE_THREAD_GROUP,
and PR_SCHED_CORE_SCOPE_PROCESS_GROUP. They simply express what
happens.
This has been on the mailing list for quite a while with all relevant
scheduler folks Cced. I announced multiple times that I'd pick this up
if I don't see or her anyone else doing it. None of this touches
proper scheduler code but only concerns uapi so I think this is fine.
With core scheduling being quite common now for vm managers (e.g.
moving individual vcpu threads into their own core scheduling domain)
and container managers (e.g. moving the init process into its own core
scheduling domain and letting all created children inherit it) having
to rely on raw numbers passed as the 4th argument in prctl() is a bit
annoying and everyone is starting to come up with their own defines"
* tag 'kernel.sys.v5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
uapi/linux/prctl: provide macro definitions for the PR_SCHED_CORE type argument
|
|
|
Linus Torvalds
|
512b7931ad |
Merge branch 'akpm' (patches from Andrew)
Merge misc updates from Andrew Morton: "257 patches. Subsystems affected by this patch series: scripts, ocfs2, vfs, and mm (slab-generic, slab, slub, kconfig, dax, kasan, debug, pagecache, gup, swap, memcg, pagemap, mprotect, mremap, iomap, tracing, vmalloc, pagealloc, memory-failure, hugetlb, userfaultfd, vmscan, tools, memblock, oom-kill, hugetlbfs, migration, thp, readahead, nommu, ksm, vmstat, madvise, memory-hotplug, rmap, zsmalloc, highmem, zram, cleanups, kfence, and damon)" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (257 commits) mm/damon: remove return value from before_terminate callback mm/damon: fix a few spelling mistakes in comments and a pr_debug message mm/damon: simplify stop mechanism Docs/admin-guide/mm/pagemap: wordsmith page flags descriptions Docs/admin-guide/mm/damon/start: simplify the content Docs/admin-guide/mm/damon/start: fix a wrong link Docs/admin-guide/mm/damon/start: fix wrong example commands mm/damon/dbgfs: add adaptive_targets list check before enable monitor_on mm/damon: remove unnecessary variable initialization Documentation/admin-guide/mm/damon: add a document for DAMON_RECLAIM mm/damon: introduce DAMON-based Reclamation (DAMON_RECLAIM) selftests/damon: support watermarks mm/damon/dbgfs: support watermarks mm/damon/schemes: activate schemes based on a watermarks mechanism tools/selftests/damon: update for regions prioritization of schemes mm/damon/dbgfs: support prioritization weights mm/damon/vaddr,paddr: support pageout prioritization mm/damon/schemes: prioritize regions within the quotas mm/damon/selftests: support schemes quotas mm/damon/dbgfs: support quotas of schemes ... |
|
Geert Uytterhoeven
|
61bb6cd2f7 |
mm: move node_reclaim_distance to fix NUMA without SMP
Patch series "Fix NUMA without SMP".
SuperH is the only architecture which still supports NUMA without SMP,
for good reasons (various memories scattered around the address space,
each with varying latencies).
This series fixes two build errors due to variables and functions used
by the NUMA code being provided by SMP-only source files or sections.
This patch (of 2):
If CONFIG_NUMA=y, but CONFIG_SMP=n (e.g. sh/migor_defconfig):
sh4-linux-gnu-ld: mm/page_alloc.o: in function `get_page_from_freelist':
page_alloc.c:(.text+0x2c24): undefined reference to `node_reclaim_distance'
Fix this by moving the declaration of node_reclaim_distance from an
SMP-only to a generic file.
Link: https://lkml.kernel.org/r/cover.1631781495.git.geert+renesas@glider.be
Link: https://lkml.kernel.org/r/6432666a648dde85635341e6c918cee97c97d264.1631781495.git.geert+renesas@glider.be
Fixes:
|
|
|
Linus Torvalds
|
01463374c5 |
cpu-to-thread_info update for v5.16-rc1
Cross-architecture update to move task_struct::cpu back into thread_info
on arm64, x86, s390, powerpc, and riscv. All Acked by arch maintainers.
Quoting Ard Biesheuvel:
"Move task_struct::cpu back into thread_info
Keeping CPU in task_struct is problematic for architectures that define
raw_smp_processor_id() in terms of this field, as it requires
linux/sched.h to be included, which causes a lot of pain in terms of
circular dependencies (aka 'header soup')
This series moves it back into thread_info (where it came from) for all
architectures that enable THREAD_INFO_IN_TASK, addressing the header
soup issue as well as some pointless differences in the implementations
of task_cpu() and set_task_cpu()."
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Merge tag 'cpu-to-thread_info-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull thread_info update to move 'cpu' back from task_struct from Kees Cook:
"Cross-architecture update to move task_struct::cpu back into
thread_info on arm64, x86, s390, powerpc, and riscv. All Acked by arch
maintainers.
Quoting Ard Biesheuvel:
'Move task_struct::cpu back into thread_info
Keeping CPU in task_struct is problematic for architectures that
define raw_smp_processor_id() in terms of this field, as it
requires linux/sched.h to be included, which causes a lot of pain
in terms of circular dependencies (aka 'header soup')
This series moves it back into thread_info (where it came from)
for all architectures that enable THREAD_INFO_IN_TASK, addressing
the header soup issue as well as some pointless differences in the
implementations of task_cpu() and set_task_cpu()'"
* tag 'cpu-to-thread_info-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
riscv: rely on core code to keep thread_info::cpu updated
powerpc: smp: remove hack to obtain offset of task_struct::cpu
sched: move CPU field back into thread_info if THREAD_INFO_IN_TASK=y
powerpc: add CPU field to struct thread_info
s390: add CPU field to struct thread_info
x86: add CPU field to struct thread_info
arm64: add CPU field to struct thread_info
|
|
|
Linus Torvalds
|
9a7e0a90a4 |
Scheduler updates:
- Revert the printk format based wchan() symbol resolution as it can leak
the raw value in case that the symbol is not resolvable.
- Make wchan() more robust and work with all kind of unwinders by
enforcing that the task stays blocked while unwinding is in progress.
- Prevent sched_fork() from accessing an invalid sched_task_group
- Improve asymmetric packing logic
- Extend scheduler statistics to RT and DL scheduling classes and add
statistics for bandwith burst to the SCHED_FAIR class.
- Properly account SCHED_IDLE entities
- Prevent a potential deadlock when initial priority is assigned to a
newly created kthread. A recent change to plug a race between cpuset and
__sched_setscheduler() introduced a new lock dependency which is now
triggered. Break the lock dependency chain by moving the priority
assignment to the thread function.
- Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.
- Improve idle balancing in general and especially for NOHZ enabled
systems.
- Provide proper interfaces for live patching so it does not have to
fiddle with scheduler internals.
- Add cluster aware scheduling support.
- A small set of tweaks for RT (irqwork, wait_task_inactive(), various
scheduler options and delaying mmdrop)
- The usual small tweaks and improvements all over the place
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Merge tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Thomas Gleixner:
- Revert the printk format based wchan() symbol resolution as it can
leak the raw value in case that the symbol is not resolvable.
- Make wchan() more robust and work with all kind of unwinders by
enforcing that the task stays blocked while unwinding is in progress.
- Prevent sched_fork() from accessing an invalid sched_task_group
- Improve asymmetric packing logic
- Extend scheduler statistics to RT and DL scheduling classes and add
statistics for bandwith burst to the SCHED_FAIR class.
- Properly account SCHED_IDLE entities
- Prevent a potential deadlock when initial priority is assigned to a
newly created kthread. A recent change to plug a race between cpuset
and __sched_setscheduler() introduced a new lock dependency which is
now triggered. Break the lock dependency chain by moving the priority
assignment to the thread function.
- Fix the idle time reporting in /proc/uptime for NOHZ enabled systems.
- Improve idle balancing in general and especially for NOHZ enabled
systems.
- Provide proper interfaces for live patching so it does not have to
fiddle with scheduler internals.
- Add cluster aware scheduling support.
- A small set of tweaks for RT (irqwork, wait_task_inactive(), various
scheduler options and delaying mmdrop)
- The usual small tweaks and improvements all over the place
* tag 'sched-core-2021-11-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (69 commits)
sched/fair: Cleanup newidle_balance
sched/fair: Remove sysctl_sched_migration_cost condition
sched/fair: Wait before decaying max_newidle_lb_cost
sched/fair: Skip update_blocked_averages if we are defering load balance
sched/fair: Account update_blocked_averages in newidle_balance cost
x86: Fix __get_wchan() for !STACKTRACE
sched,x86: Fix L2 cache mask
sched/core: Remove rq_relock()
sched: Improve wake_up_all_idle_cpus() take #2
irq_work: Also rcuwait for !IRQ_WORK_HARD_IRQ on PREEMPT_RT
irq_work: Handle some irq_work in a per-CPU thread on PREEMPT_RT
irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.
sched/rt: Annotate the RT balancing logic irqwork as IRQ_WORK_HARD_IRQ
sched: Add cluster scheduler level for x86
sched: Add cluster scheduler level in core and related Kconfig for ARM64
topology: Represent clusters of CPUs within a die
sched: Disable -Wunused-but-set-variable
sched: Add wrapper for get_wchan() to keep task blocked
x86: Fix get_wchan() to support the ORC unwinder
proc: Use task_is_running() for wchan in /proc/$pid/stat
...
|
|
|
Linus Torvalds
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595b28fb0c |
Locking updates:
- Move futex code into kernel/futex/ and split up the kitchen sink into
seperate files to make integration of sys_futex_waitv() simpler.
- Add a new sys_futex_waitv() syscall which allows to wait on multiple
futexes. The main use case is emulating Windows' WaitForMultipleObjects
which allows Wine to improve the performance of Windows Games. Also
native Linux games can benefit from this interface as this is a common
wait pattern for this kind of applications.
- Add context to ww_mutex_trylock() to provide a path for i915 to rework
their eviction code step by step without making lockdep upset until the
final steps of rework are completed. It's also useful for regulator and
TTM to avoid dropping locks in the non contended path.
- Lockdep and might_sleep() cleanups and improvements
- A few improvements for the RT substitutions.
- The usual small improvements and cleanups.
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Merge tag 'locking-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Thomas Gleixner:
- Move futex code into kernel/futex/ and split up the kitchen sink into
seperate files to make integration of sys_futex_waitv() simpler.
- Add a new sys_futex_waitv() syscall which allows to wait on multiple
futexes.
The main use case is emulating Windows' WaitForMultipleObjects which
allows Wine to improve the performance of Windows Games. Also native
Linux games can benefit from this interface as this is a common wait
pattern for this kind of applications.
- Add context to ww_mutex_trylock() to provide a path for i915 to
rework their eviction code step by step without making lockdep upset
until the final steps of rework are completed. It's also useful for
regulator and TTM to avoid dropping locks in the non contended path.
- Lockdep and might_sleep() cleanups and improvements
- A few improvements for the RT substitutions.
- The usual small improvements and cleanups.
* tag 'locking-core-2021-10-31' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (44 commits)
locking: Remove spin_lock_flags() etc
locking/rwsem: Fix comments about reader optimistic lock stealing conditions
locking: Remove rcu_read_{,un}lock() for preempt_{dis,en}able()
locking/rwsem: Disable preemption for spinning region
docs: futex: Fix kernel-doc references
futex: Fix PREEMPT_RT build
futex2: Documentation: Document sys_futex_waitv() uAPI
selftests: futex: Test sys_futex_waitv() wouldblock
selftests: futex: Test sys_futex_waitv() timeout
selftests: futex: Add sys_futex_waitv() test
futex,arm: Wire up sys_futex_waitv()
futex,x86: Wire up sys_futex_waitv()
futex: Implement sys_futex_waitv()
futex: Simplify double_lock_hb()
futex: Split out wait/wake
futex: Split out requeue
futex: Rename mark_wake_futex()
futex: Rename: match_futex()
futex: Rename: hb_waiter_{inc,dec,pending}()
futex: Split out PI futex
...
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|
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Linus Torvalds
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33c8846c81 |
for-5.16/block-2021-10-29
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Vincent Guittot
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8ea9183db4 |
sched/fair: Cleanup newidle_balance
update_next_balance() uses sd->last_balance which is not modified by load_balance() so we can merge the 2 calls in one place. No functional change Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Acked-by: Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20211019123537.17146-6-vincent.guittot@linaro.org |
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Vincent Guittot
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c5b0a7eefc |
sched/fair: Remove sysctl_sched_migration_cost condition
With a default value of 500us, sysctl_sched_migration_cost is significanlty higher than the cost of load_balance. Remove the condition and rely on the sd->max_newidle_lb_cost to abort newidle_balance. Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Acked-by: Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20211019123537.17146-5-vincent.guittot@linaro.org |
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Vincent Guittot
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e60b56e46b |
sched/fair: Wait before decaying max_newidle_lb_cost
Decay max_newidle_lb_cost only when it has not been updated for a while and ensure to not decay a recently changed value. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Acked-by: Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20211019123537.17146-4-vincent.guittot@linaro.org |
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Vincent Guittot
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9d783c8dd1 |
sched/fair: Skip update_blocked_averages if we are defering load balance
In newidle_balance(), the scheduler skips load balance to the new idle cpu when the 1st sd of this_rq is: this_rq->avg_idle < sd->max_newidle_lb_cost Doing a costly call to update_blocked_averages() will not be useful and simply adds overhead when this condition is true. Check the condition early in newidle_balance() to skip update_blocked_averages() when possible. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Acked-by: Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20211019123537.17146-3-vincent.guittot@linaro.org |
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Vincent Guittot
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9e9af819db |
sched/fair: Account update_blocked_averages in newidle_balance cost
The time spent to update the blocked load can be significant depending of the complexity fo the cgroup hierarchy. Take this time into account in the cost of the 1st load balance of a newly idle cpu. Also reduce the number of call to sched_clock_cpu() and track more actual work. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Acked-by: Mel Gorman <mgorman@suse.de> Link: https://lore.kernel.org/r/20211019123537.17146-2-vincent.guittot@linaro.org |
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Peng Wang
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eaed27d0d0 |
sched/core: Remove rq_relock()
After the removal of migrate_tasks(), there is no user of rq_relock() left, so remove it. Signed-off-by: Peng Wang <rocking@linux.alibaba.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/449948fdf9be4764b3929c52572917dd25eef758.1634611953.git.rocking@linux.alibaba.com |
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Christoph Hellwig
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008f75a20e |
block: cleanup the flush plug helpers
Consolidate the various helpers into a single blk_flush_plug helper that takes a plk_plug and the from_scheduler bool and switch all callsites to call it directly. Checks that the plug is non-NULL must be performed by the caller, something that most already do anyway. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20211020144119.142582-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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Woody Lin
|
63acd42c0d |
sched/scs: Reset the shadow stack when idle_task_exit
Commit |