Peter Zijlstra
39a4364076
perf: Fix task context scheduling ...
There is a very nasty problem wrt disabling the perf task scheduling
hooks.
Currently we {set,clear} ctx->is_active on every
__perf_event_task_sched_{in,out}, _however_ this means that if we
disable these calls we'll have task contexts with ->is_active set that
are not active and 'active' task contexts without ->is_active set.
This can result in event_function_call() looping on the ctx->is_active
condition basically indefinitely.
Resolve this by changing things such that contexts without events do
not set ->is_active like we used to. From this invariant it trivially
follows that if there are no (task) events, every task ctx is inactive
and disabling the context switch hooks is harmless.
This leaves two places that need attention (and already had
accumulated weird and wonderful hacks to work around, without
recognising this actual problem).
Namely:
- perf_install_in_context() will need to deal with installing events
in an inactive context, meaning it cannot rely on ctx-is_active for
its IPIs.
- perf_remove_from_context() will have to mark a context as inactive
when it removes the last event.
For specific detail, see the patch/comments.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-01-21 18:54:23 +01:00
net: bpf: reject invalid shifts
2016-01-12 17:06:53 -05:00
kconfig: add xenconfig defconfig helper
2015-06-16 11:04:29 +01:00
perf: Fix task context scheduling
2016-01-21 18:54:23 +01:00
gcov: add support for GCC 5.1
2015-06-30 19:44:57 -07:00
Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-01-11 18:28:06 -08:00
livepatch: x86: fix relocation computation with kASLR
2015-11-11 17:36:04 +01:00
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-01-11 14:18:38 -08:00
PM / sleep: Add support for read-only sysfs attributes
2016-01-04 22:28:59 +01:00
printk: prevent userland from spoofing kernel messages
2015-11-06 17:50:42 -08:00
Merge branches 'doc.2015.12.05a', 'exp.2015.12.07a', 'fixes.2015.12.07a', 'list.2015.12.04b' and 'torture.2015.12.05a' into HEAD
2015-12-07 17:02:54 -08:00
Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2016-01-12 19:20:32 -08:00
Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2016-01-11 18:53:13 -08:00
Not much new with tracing for this release. Mostly just clean ups and
2016-01-12 20:04:15 -08:00
certs: add .gitignore to stop git nagging about x509_certificate_list
2015-10-21 15:18:35 +01:00
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
2015-11-06 17:50:42 -08:00
audit: audit_tree_match can be boolean
2015-11-04 08:23:51 -05:00
audit: clean simple fsnotify implementation
2015-08-06 16:14:53 -04:00
audit: audit_tree_match can be boolean
2015-11-04 08:23:51 -05:00
Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit
2015-09-08 13:34:59 -07:00
audit: fix comment block whitespace
2015-11-04 08:23:51 -05:00
Merge branch 'upstream' of git://git.infradead.org/users/pcmoore/audit
2015-09-08 13:34:59 -07:00
Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2016-01-12 19:20:32 -08:00
cgroup: kill cgrp_ss_priv[CGROUP_CANFORK_COUNT] and friends
2015-12-03 10:24:08 -05:00
cgroup_pids: fix a typo.
2015-12-14 14:54:37 -05:00
context_tracking: Switch to new static_branch API
2015-11-24 09:56:43 +01:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2015-11-03 18:03:50 -08:00
kernel/cpu_pm: fix cpu_cluster_pm_exit comment
2015-09-03 02:42:20 +02:00
Merge branch 'for-4.4-fixes' into for-4.5
2015-12-03 10:22:52 -05:00
kernel/cred.c: remove unnecessary kdebug atomic reads
2015-09-10 13:29:01 -07:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2015-11-03 18:03:50 -08:00
kernel/extable.c: remove duplicated include
2015-09-10 13:29:01 -07:00
Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2016-01-12 19:20:32 -08:00
futex: Allow FUTEX_CLOCK_REALTIME with FUTEX_WAIT op
2015-12-20 12:43:25 +01:00
treewide: Remove old email address
2015-11-23 09:44:58 +01:00
treewide: Remove old email address
2015-11-23 09:44:58 +01:00
kexec: use file name as the output message prefix
2015-11-06 17:50:42 -08:00
kexec: Fix race between panic() and crash_kexec()
2015-12-19 11:07:01 +01:00
kexec: use file name as the output message prefix
2015-11-06 17:50:42 -08:00
kexec: split kexec_file syscall code to kexec_file.c
2015-09-10 13:29:01 -07:00
kmod: don't run async usermode helper as a child of kworker thread
2015-10-23 17:55:10 +09:00
perf/x86/hw_breakpoints: Disallow kernel breakpoints unless kprobe-safe
2015-08-04 10:16:54 +02:00
rcu: Remove TINY_RCU bloat from pointless boot parameters
2015-12-07 16:59:37 -08:00
kernel/kthread.c:kthread_create_on_node(): clarify documentation
2015-09-04 16:54:41 -07:00
sys_membarrier(): system-wide memory barrier (generic, x86)
2015-09-11 15:21:34 -07:00
sys_membarrier(): system-wide memory barrier (generic, x86)
2015-09-11 15:21:34 -07:00
libnvdimm for 4.4:
2015-11-10 12:07:22 -08:00
ftrace/module: Call clean up function when module init fails early
2016-01-07 12:17:39 -05:00
KEYS: Merge the type-specific data with the payload data
2015-10-21 15:18:36 +01:00
Merge branch 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2015-09-01 08:40:25 -07:00
kexec: Fix race between panic() and crash_kexec()
2015-12-19 11:07:01 +01:00
Nothing exciting, minor tweaks and cleanups.
2015-11-09 15:53:39 -08:00
pidns: fix NULL dereference in __task_pid_nr_ns()
2015-11-24 12:03:55 -08:00
mm: rename alloc_pages_exact_node() to __alloc_pages_node()
2015-09-08 15:35:28 -07:00
seccomp, ptrace: add support for dumping seccomp filters
2015-10-27 19:55:13 -07:00
kexec: split kexec_load syscall from kexec core code
2015-09-10 13:29:01 -07:00
kernel/relay.c: use kvfree() in relay_free_page_array()
2015-06-30 19:44:59 -07:00
restrict /dev/mem to idle io memory ranges
2016-01-09 06:30:49 -08:00
seccomp, ptrace: add support for dumping seccomp filters
2015-10-27 19:55:13 -07:00
kernel/signal.c: unexport sigsuspend()
2015-11-20 16:17:32 -08:00
mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
2015-11-06 17:50:42 -08:00
stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark()
2015-10-20 10:23:55 +02:00
Merge branch 'sched/urgent' into sched/core, to pick up fixes before merging new patches
2016-01-06 11:02:29 +01:00
pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode
2015-11-06 17:50:42 -08:00
vfs: add copy_file_range syscall and vfs helper
2015-12-01 14:00:53 -05:00
kernel/*: switch to memdup_user_nul()
2016-01-04 10:27:55 -05:00
task_work: remove fifo ordering guarantee
2015-09-05 13:46:58 -07:00
torture: Consolidate cond_resched_rcu_qs() into stutter_wait()
2015-10-06 11:25:01 -07:00
tracepoint: Give priority to probes of tracepoints
2015-10-25 21:33:54 -04:00
kernel/*: switch to memdup_user_nul()
2016-01-04 10:27:55 -05:00
Merge branch 'for-4.5' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
2016-01-11 18:53:13 -08:00
workqueue: simplify the apply_workqueue_attrs_locked()
2016-01-07 11:04:34 -05:00
39a4364076