mirror of
https://gitee.com/bianbu-linux/linux-6.6
synced 2025-04-24 14:07:52 -04:00
Scheduler updates for this cycle are:
- Clean up SCHED_DEBUG: move the decades old mess of sysctl, procfs and debugfs interfaces
to a unified debugfs interface.
- Signals: Allow caching one sigqueue object per task, to improve performance & latencies.
- Improve newidle_balance() irq-off latencies on systems with a large number of CPU cgroups.
- Improve energy-aware scheduling
- Improve the PELT metrics for certain workloads
- Reintroduce select_idle_smt() to improve load-balancing locality - but without the previous
regressions
- Add 'scheduler latency debugging': warn after long periods of pending need_resched. This
is an opt-in feature that requires the enabling of the LATENCY_WARN scheduler feature,
or the use of the resched_latency_warn_ms=xx boot parameter.
- CPU hotplug fixes for HP-rollback, and for the 'fail' interface. Fix remaining
balance_push() vs. hotplug holes/races
- PSI fixes, plus allow /proc/pressure/ files to be written by CAP_SYS_RESOURCE tasks as well
- Fix/improve various load-balancing corner cases vs. capacity margins
- Fix sched topology on systems with NUMA diameter of 3 or above
- Fix PF_KTHREAD vs to_kthread() race
- Minor rseq optimizations
- Misc cleanups, optimizations, fixes and smaller updates
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
- Clean up SCHED_DEBUG: move the decades old mess of sysctl, procfs and
debugfs interfaces to a unified debugfs interface.
- Signals: Allow caching one sigqueue object per task, to improve
performance & latencies.
- Improve newidle_balance() irq-off latencies on systems with a large
number of CPU cgroups.
- Improve energy-aware scheduling
- Improve the PELT metrics for certain workloads
- Reintroduce select_idle_smt() to improve load-balancing locality -
but without the previous regressions
- Add 'scheduler latency debugging': warn after long periods of pending
need_resched. This is an opt-in feature that requires the enabling of
the LATENCY_WARN scheduler feature, or the use of the
resched_latency_warn_ms=xx boot parameter.
- CPU hotplug fixes for HP-rollback, and for the 'fail' interface. Fix
remaining balance_push() vs. hotplug holes/races
- PSI fixes, plus allow /proc/pressure/ files to be written by
CAP_SYS_RESOURCE tasks as well
- Fix/improve various load-balancing corner cases vs. capacity margins
- Fix sched topology on systems with NUMA diameter of 3 or above
- Fix PF_KTHREAD vs to_kthread() race
- Minor rseq optimizations
- Misc cleanups, optimizations, fixes and smaller updates
* tag 'sched-core-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (61 commits)
cpumask/hotplug: Fix cpu_dying() state tracking
kthread: Fix PF_KTHREAD vs to_kthread() race
sched/debug: Fix cgroup_path[] serialization
sched,psi: Handle potential task count underflow bugs more gracefully
sched: Warn on long periods of pending need_resched
sched/fair: Move update_nohz_stats() to the CONFIG_NO_HZ_COMMON block to simplify the code & fix an unused function warning
sched/debug: Rename the sched_debug parameter to sched_verbose
sched,fair: Alternative sched_slice()
sched: Move /proc/sched_debug to debugfs
sched,debug: Convert sysctl sched_domains to debugfs
debugfs: Implement debugfs_create_str()
sched,preempt: Move preempt_dynamic to debug.c
sched: Move SCHED_DEBUG sysctl to debugfs
sched: Don't make LATENCYTOP select SCHED_DEBUG
sched: Remove sched_schedstats sysctl out from under SCHED_DEBUG
sched/numa: Allow runtime enabling/disabling of NUMA balance without SCHED_DEBUG
sched: Use cpu_dying() to fix balance_push vs hotplug-rollback
cpumask: Introduce DYING mask
cpumask: Make cpu_{online,possible,present,active}() inline
rseq: Optimise rseq_get_rseq_cs() and clear_rseq_cs()
...
This commit is contained in:
Linus Torvalds
commit
16b3d0cf5b
46 changed files with 1305 additions and 921 deletions
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@ -408,7 +408,8 @@ void task_join_group_stop(struct task_struct *task)
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* appropriate lock must be held to stop the target task from exiting
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*/
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static struct sigqueue *
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__sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimit)
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__sigqueue_alloc(int sig, struct task_struct *t, gfp_t gfp_flags,
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int override_rlimit, const unsigned int sigqueue_flags)
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{
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struct sigqueue *q = NULL;
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struct user_struct *user;
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@ -430,7 +431,16 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimi
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rcu_read_unlock();
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if (override_rlimit || likely(sigpending <= task_rlimit(t, RLIMIT_SIGPENDING))) {
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q = kmem_cache_alloc(sigqueue_cachep, flags);
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/*
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* Preallocation does not hold sighand::siglock so it can't
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* use the cache. The lockless caching requires that only
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* one consumer and only one producer run at a time.
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*/
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q = READ_ONCE(t->sigqueue_cache);
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if (!q || sigqueue_flags)
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q = kmem_cache_alloc(sigqueue_cachep, gfp_flags);
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else
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WRITE_ONCE(t->sigqueue_cache, NULL);
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} else {
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print_dropped_signal(sig);
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}
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@ -440,20 +450,51 @@ __sigqueue_alloc(int sig, struct task_struct *t, gfp_t flags, int override_rlimi
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free_uid(user);
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} else {
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INIT_LIST_HEAD(&q->list);
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q->flags = 0;
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q->flags = sigqueue_flags;
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q->user = user;
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}
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return q;
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}
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void exit_task_sigqueue_cache(struct task_struct *tsk)
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{
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/* Race free because @tsk is mopped up */
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struct sigqueue *q = tsk->sigqueue_cache;
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if (q) {
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tsk->sigqueue_cache = NULL;
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/*
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* Hand it back to the cache as the task might
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* be self reaping which would leak the object.
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*/
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kmem_cache_free(sigqueue_cachep, q);
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}
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}
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static void sigqueue_cache_or_free(struct sigqueue *q)
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{
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/*
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* Cache one sigqueue per task. This pairs with the consumer side
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* in __sigqueue_alloc() and needs READ/WRITE_ONCE() to prevent the
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* compiler from store tearing and to tell KCSAN that the data race
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* is intentional when run without holding current->sighand->siglock,
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* which is fine as current obviously cannot run __sigqueue_free()
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* concurrently.
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*/
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if (!READ_ONCE(current->sigqueue_cache))
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WRITE_ONCE(current->sigqueue_cache, q);
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else
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kmem_cache_free(sigqueue_cachep, q);
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}
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static void __sigqueue_free(struct sigqueue *q)
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{
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if (q->flags & SIGQUEUE_PREALLOC)
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return;
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if (atomic_dec_and_test(&q->user->sigpending))
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free_uid(q->user);
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kmem_cache_free(sigqueue_cachep, q);
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sigqueue_cache_or_free(q);
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}
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void flush_sigqueue(struct sigpending *queue)
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@ -1111,7 +1152,8 @@ static int __send_signal(int sig, struct kernel_siginfo *info, struct task_struc
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else
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override_rlimit = 0;
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q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit);
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q = __sigqueue_alloc(sig, t, GFP_ATOMIC, override_rlimit, 0);
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if (q) {
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list_add_tail(&q->list, &pending->list);
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switch ((unsigned long) info) {
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@ -1806,12 +1848,7 @@ EXPORT_SYMBOL(kill_pid);
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*/
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struct sigqueue *sigqueue_alloc(void)
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{
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struct sigqueue *q = __sigqueue_alloc(-1, current, GFP_KERNEL, 0);
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if (q)
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q->flags |= SIGQUEUE_PREALLOC;
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return q;
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return __sigqueue_alloc(-1, current, GFP_KERNEL, 0, SIGQUEUE_PREALLOC);
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}
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void sigqueue_free(struct sigqueue *q)
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