Peter Zijlstra
3ca0ff571b
locking/mutex: Rework mutex::owner ...
The current mutex implementation has an atomic lock word and a
non-atomic owner field.
This disparity leads to a number of issues with the current mutex code
as it means that we can have a locked mutex without an explicit owner
(because the owner field has not been set, or already cleared).
This leads to a number of weird corner cases, esp. between the
optimistic spinning and debug code. Where the optimistic spinning
code needs the owner field updated inside the lock region, the debug
code is more relaxed because the whole lock is serialized by the
wait_lock.
Also, the spinning code itself has a few corner cases where we need to
deal with a held lock without an owner field.
Furthermore, it becomes even more of a problem when trying to fix
starvation cases in the current code. We end up stacking special case
on special case.
To solve this rework the basic mutex implementation to be a single
atomic word that contains the owner and uses the low bits for extra
state.
This matches how PI futexes and rt_mutex already work. By having the
owner an integral part of the lock state a lot of the problems
dissapear and we get a better option to deal with starvation cases,
direct owner handoff.
Changing the basic mutex does however invalidate all the arch specific
mutex code; this patch leaves that unused in-place, a later patch will
remove that.
Tested-by: Jason Low <jason.low2@hpe.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-10-25 11:31:50 +02:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2016-10-10 20:16:43 -07:00
config: android: enable CONFIG_SECCOMP
2016-10-11 15:06:32 -07:00
mm: replace get_user_pages_remote() write/force parameters with gup_flags
2016-10-19 08:12:02 -07:00
gcov: add support for gcc version >= 6
2016-07-15 14:54:27 +09:00
kernel/irq: Export irq_set_parent()
2016-10-21 10:21:38 +02:00
livepatch/module: make TAINT_LIVEPATCH module-specific
2016-08-26 14:42:08 +02:00
locking/mutex: Rework mutex::owner
2016-10-25 11:31:50 +02:00
oom, suspend: fix oom_killer_disable vs. pm suspend properly
2016-10-07 18:46:27 -07:00
printk: suppress empty continuation lines
2016-10-19 09:11:24 -07:00
This adds a new gcc plugin named "latent_entropy". It is designed to
2016-10-15 10:03:15 -07:00
locking/mutex: Rework mutex::owner
2016-10-25 11:31:50 +02:00
alarmtimer: Remove unused but set variable
2016-10-17 11:59:37 +02:00
Disable the __builtin_return_address() warning globally after all
2016-10-12 10:23:41 -07:00
Merge branch 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit
2016-10-04 14:21:41 -07:00
Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit
2016-07-29 17:54:17 -07:00
Merge branch 'stable-4.8' of git://git.infradead.org/users/pcmoore/audit
2016-09-01 15:55:56 -07:00
audit: add fields to exclude filter by reusing user filter
2016-06-27 11:01:00 -04:00
Merge branch 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit
2016-10-04 14:21:41 -07:00
kernel: Add noaudit variant of ns_capable()
2016-06-06 20:16:18 +10:00
Merge branch 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2016-10-14 12:18:50 -07:00
cgroup: Use lld instead of ld when printing pids controller events_limit
2016-06-21 15:03:36 -04:00
cpu/hotplug: Use distinct name for cpu_hotplug.dep_map
2016-10-16 11:09:32 +02:00
Merge branch 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
2016-10-14 12:18:50 -07:00
cred: Reject inodes with invalid ids in set_create_file_as()
2016-06-30 18:05:09 -05:00
mm, oom: enforce exit_oom_victim on current task
2016-10-07 18:46:28 -07:00
This adds a new gcc plugin named "latent_entropy". It is designed to
2016-10-15 10:03:15 -07:00
freezer, oom: check TIF_MEMDIE on the correct task
2016-07-28 16:07:41 -07:00
futex: Add some more function commentry
2016-09-05 17:20:18 +02:00
cred: simpler, 1D supplementary groups
2016-10-07 18:46:30 -07:00
hung_task: allow hung_task_panic when hung_task_warnings is 0
2016-10-11 15:06:33 -07:00
powerpc updates for 4.8 #2
2016-08-05 09:00:54 -04:00
kernel/kcov: unproxify debugfs file's fops
2016-06-15 04:56:35 -07:00
kexec: allow architectures to override boot mapping
2016-08-02 19:35:27 -04:00
kexec: add restriction on kexec_load() segment sizes
2016-08-02 19:35:31 -04:00
kexec: fix double-free when failing to relocate the purgatory
2016-09-01 17:52:01 -07:00
kprobes: include <asm/sections.h> instead of <asm-generic/sections.h>
2016-10-11 15:06:31 -07:00
kexec: add a kexec_crash_loaded() function
2016-08-02 19:35:30 -04:00
kthread: better support freezable kthread workers
2016-10-11 15:06:33 -07:00
userns: Add per user namespace sysctls.
2016-08-08 13:18:58 -05:00
mm: fix cache mode of dax pmd mappings
2016-09-09 17:34:46 -07:00
livepatch/module: make TAINT_LIVEPATCH module-specific
2016-08-26 14:42:08 +02:00
padata: Convert to hotplug state machine
2016-09-19 21:44:30 +02:00
x86/panic: replace smp_send_stop() with kdump friendly version in panic path
2016-10-11 15:06:32 -07:00
Merge branch 'nsfs-ioctls' into HEAD
2016-09-22 20:00:36 -05:00
profile: Convert to hotplug state machine
2016-07-15 10:41:42 +02:00
mm: replace access_process_vm() write parameter with gup_flags
2016-10-19 08:31:25 -07:00
relay: Use irq_work instead of plain timer for deferred wakeup
2016-10-11 15:06:32 -07:00
seccomp: Fix tracer exit notifications during fatal signals
2016-08-30 16:12:46 -07:00
x86/signal: Add SA_{X32,IA32}_ABI sa_flags
2016-09-14 21:28:11 +02:00
smp: Allocate smp_call_on_cpu() workqueue on stack too
2016-09-22 14:49:10 +02:00
kthread/smpboot: do not park in kthread_create_on_cpu()
2016-10-11 15:06:33 -07:00
This adds a new gcc plugin named "latent_entropy". It is designed to
2016-10-15 10:03:15 -07:00
Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
2016-10-03 13:39:00 -07:00
x86/pkeys: Fix pkeys build breakage for some non-x86 arches
2016-09-13 14:41:36 +02:00
Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
2016-10-10 13:04:49 -07:00
task_work: use READ_ONCE/lockless_dereference, avoid pi_lock if !task_works
2016-08-02 19:35:02 -04:00
torture: Convert torture_shutdown() to hrtimer
2016-08-22 10:01:49 -07:00
mntns: Add a limit on the number of mount namespaces.
2016-08-31 07:28:35 -05:00
cred: simpler, 1D supplementary groups
2016-10-07 18:46:30 -07:00
smp: Add function to execute a function synchronously on a CPU
2016-09-05 13:52:39 +02:00
Merge branch 'nsfs-ioctls' into HEAD
2016-09-22 20:00:36 -05:00
Merge branch 'nsfs-ioctls' into HEAD
2016-09-22 20:00:36 -05:00
Revert "perf/x86/intel, watchdog: Switch NMI watchdog to ref cycles on x86"
2016-07-10 20:58:36 +02:00
kthread: rename probe_kthread_data() to kthread_probe_data()
2016-10-11 15:06:33 -07:00
3ca0ff571b