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b5d9d734a5
android_kernel_xiaomi_sm8350/kernel
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Mike Galbraith b5d9d734a5 sched: Ensure that a child can't gain time over it's parent after fork() 
A fork/exec load is usually "pass the baton", so the child
should never be placed behind the parent.  With START_DEBIT we
make room for the new task, but with child_runs_first, that
room comes out of the _parent's_ hide. There's nothing to say
that the parent wasn't ahead of min_vruntime at fork() time,
which means that the "baton carrier", who is essentially the
parent in drag, can gain time and increase scheduling latencies
for waiters.

With NEW_FAIR_SLEEPERS + START_DEBIT + child_runs_first
enabled, we essentially pass the sleeper fairness off to the
child, which is fine, but if we don't base placement on the
parent's updated vruntime, we can end up compounding latency
woes if the child itself then does fork/exec.  The debit
incurred at fork doesn't hurt the parent who is then going to
sleep and maybe exit, but the child who acquires the error
harms all comers.

This improves latencies of make -j<n> kernel build workloads.

Reported-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-09-08 13:15:34 +02:00
..
gcov gcov: enable GCOV_PROFILE_ALL for x86_64 2009-06-18 13:03:58 -07:00
irq genirq: Wake up irq thread after action has been installed 2009-08-18 17:22:43 +02:00
power headers: smp_lock.h redux 2009-07-12 12:22:34 -07:00
time clockevent: Prevent dead lock on clockevents_lock 2009-08-19 18:15:10 +02:00
trace tracing: handle broken names in ftrace filter 2009-08-18 20:39:48 -04:00
.gitignore
acct.c bsdacct: fix access to invalid filp in acct_on() 2009-06-30 18:56:00 -07:00
async.c async: Fix lack of boot-time console due to insufficient synchronization 2009-06-08 12:31:53 -07:00
audit_tree.c Fix rule eviction order for AUDIT_DIR 2009-06-24 00:02:38 -04:00
audit_watch.c Audit: clean up all op= output to include string quoting 2009-06-24 00:00:52 -04:00
audit.c Fix rule eviction order for AUDIT_DIR 2009-06-24 00:02:38 -04:00
audit.h Fix rule eviction order for AUDIT_DIR 2009-06-24 00:02:38 -04:00
auditfilter.c Audit: clean up all op= output to include string quoting 2009-06-24 00:00:52 -04:00
auditsc.c Fix rule eviction order for AUDIT_DIR 2009-06-24 00:02:38 -04:00
backtracetest.c
bounds.c
capability.c
cgroup_debug.c
cgroup_freezer.c
cgroup.c cgroup avoid permanent sleep at rmdir 2009-07-29 19:10:35 -07:00
compat.c signals: implement sys_rt_tgsigqueueinfo 2009-04-30 19:24:24 +02:00
configs.c
cpu.c mm/init: cpu_hotplug_init() must be initialized before SLAB 2009-06-22 21:18:12 -07:00
cpuset.c cpuset,mm: update tasks' mems_allowed in time 2009-06-16 19:47:31 -07:00
cred-internals.h
cred.c CRED: Rename cred_exec_mutex to reflect that it's a guard against ptrace 2009-05-11 08:15:36 +10:00
delayacct.c
dma-coherent.c
dma.c
exec_domain.c
exit.c headers: mnt_namespace.h redux 2009-07-08 09:31:56 -07:00
extable.c
fork.c clone(): fix race between copy_process() and de_thread() 2009-08-26 20:06:52 -07:00
freezer.c sched: fix nr_uninterruptible accounting of frozen tasks really 2009-07-18 14:19:53 +02:00
futex_compat.c futex: Fix compat_futex to be same as futex for REQUEUE_PI 2009-08-10 15:41:12 +02:00
futex.c futex: Fix handling of bad requeue syscall pairing 2009-08-10 20:38:11 +02:00
groups.c groups: move code to kernel/groups.c 2009-06-16 19:47:48 -07:00
hrtimer.c hrtimer: Fix migration expiry check 2009-07-10 17:32:55 +02:00
hung_task.c
itimer.c
kallsyms.c kernel/kallsyms.c: replace deprecated __initcall with device_initcall and fix whitespace 2009-06-09 22:37:52 +02:00
Kconfig.freezer
Kconfig.hz
Kconfig.preempt
kexec.c kexec: fix omitting offset in extended crashkernel syntax 2009-07-29 19:10:34 -07:00
kfifo.c kernel/kfifo.c: replace conditional test with is_power_of_2() 2009-06-16 19:47:47 -07:00
kgdb.c sysrq, intel_fb: fix sysrq g collision 2009-05-15 07:56:24 -05:00
kmod.c headers: mnt_namespace.h redux 2009-07-08 09:31:56 -07:00
kprobes.c kprobes: Use kernel_text_address() for checking probe address 2009-07-30 16:44:06 -07:00
ksysfs.c
kthread.c update the comment in kthread_stop() 2009-07-27 12:15:46 -07:00
latencytop.c
lockdep_internals.h lockdep: increase MAX_LOCKDEP_ENTRIES and MAX_LOCKDEP_CHAINS 2009-05-12 19:59:52 +02:00
lockdep_proc.c lockdep: Fix file mode of lock_stat 2009-08-07 11:58:38 +02:00
lockdep_states.h
lockdep.c Merge branch 'linus' into tracing/core 2009-05-07 11:17:34 +02:00
Makefile Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-28 11:05:04 -07:00
marker.c
module.c module: workaround duplicate section names 2009-08-27 12:33:19 -07:00
mutex-debug.c
mutex-debug.h
mutex.c Merge branch 'linus' into perfcounters/core 2009-06-11 17:55:42 +02:00
mutex.h
notifier.c
ns_cgroup.c
nsproxy.c nsproxy: extract create_nsproxy() 2009-06-18 13:03:56 -07:00
panic.c trace: stop tracer in oops_enter() 2009-07-24 15:30:45 -04:00
params.c module_param: allow 'bool' module_params to be bool, not just int. 2009-06-12 21:46:58 +09:30
perf_counter.c perf_counter: Fix typo in read() output generation 2009-08-21 18:00:35 +02:00
pid_namespace.c pidns: rewrite copy_pid_ns() 2009-06-18 13:03:55 -07:00
pid.c kmemleak: Remove alloc_bootmem annotations introduced in the past 2009-07-09 17:07:02 +01:00
pm_qos_params.c
posix-cpu-timers.c posix_cpu_timers_exit_group(): Do not use thread_group_cputimer() 2009-08-08 18:30:25 +02:00
posix-timers.c posix-timers: Fix oops in clock_nanosleep() with CLOCK_MONOTONIC_RAW 2009-08-04 10:16:41 +02:00
printk.c printk: Add KERN_DEFAULT printk log-level 2009-06-16 11:02:28 -07:00
profile.c profile: suppress warning about large allocations when profile=1 is specified 2009-07-29 19:10:36 -07:00
ptrace.c cred_guard_mutex: do not return -EINTR to user-space 2009-07-06 13:57:04 -07:00
rcuclassic.c
rcupdate.c RCU: Don't try and predeclare inline funcs as it upsets some versions of gcc 2009-04-15 13:55:14 -07:00
rcupreempt_trace.c
rcupreempt.c rcu: rcu_sched_grace_period(): kill the bogus flush_signals() 2009-05-05 20:28:05 +02:00
rcutorture.c
rcutree_trace.c rcu: Add __rcu_pending tracing to hierarchical RCU 2009-04-14 11:33:43 +02:00
rcutree.c rcu: Mark Hierarchical RCU no longer experimental 2009-06-24 15:02:48 +02:00
rcutree.h
relay.c
res_counter.c memcg: add interface to reset limits 2009-06-18 13:03:48 -07:00
resource.c kernel/resource.c: fix sign extension in reserve_setup() 2009-06-30 18:56:00 -07:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c rtmutex: Avoid deadlock in rt_mutex_start_proxy_lock() 2009-08-06 05:50:21 +02:00
rtmutex.h
rwsem.c
sched_clock.c sched: Fix fallback sched_clock()'s offset when using jiffies 2009-05-09 10:08:19 +02:00
sched_cpupri.c sched: Add new prio to cpupri before removing old prio 2009-08-02 14:26:09 +02:00
sched_cpupri.h
sched_debug.c sched: Provide iowait counters 2009-09-02 08:44:08 +02:00
sched_fair.c sched: Ensure that a child can't gain time over it's parent after fork() 2009-09-08 13:15:34 +02:00
sched_features.h
sched_idletask.c sched, timers: move calc_load() to scheduler 2009-05-15 15:32:45 +02:00
sched_rt.c sched: Scale down cpu_power due to RT tasks 2009-09-04 10:09:55 +02:00
sched_stats.h
sched.c sched: Fix dynamic power-balancing crash 2009-09-04 11:52:52 +02:00
seccomp.c
semaphore.c
signal.c do_sigaltstack: small cleanups 2009-08-01 11:18:56 -07:00
slow-work.c slow-work: use round_jiffies() for thread pool's cull and OOM timers 2009-06-16 19:47:49 -07:00
smp.c generic-ipi: fix hotplug_cfd() 2009-08-07 10:39:55 -07:00
softirq.c softirq: introduce tasklet_hrtimer infrastructure 2009-07-22 17:01:17 +02:00
softlockup.c
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c
sys.c groups: move code to kernel/groups.c 2009-06-16 19:47:48 -07:00
sysctl_check.c
sysctl.c sched: Scale down cpu_power due to RT tasks 2009-09-04 10:09:55 +02:00
taskstats.c
test_kprobes.c
time.c
timeconst.pl
timer.c timer: Avoid reading uninitialized data 2009-07-18 23:11:43 +02:00
tracepoint.c
tsacct.c
uid16.c
up.c
user_namespace.c
user.c sched: delayed cleanup of user_struct 2009-06-15 21:30:23 -07:00
utsname_sysctl.c
utsname.c utsns: extract creeate_uts_ns() 2009-06-18 13:03:55 -07:00
wait.c locking, sched: Give waitqueue spinlocks their own lockdep classes 2009-08-10 14:43:09 +02:00
workqueue.c ftrace, workqueuetrace: make workqueue tracepoints use TRACE_EVENT macro 2009-06-02 01:10:40 +02:00