Mathieu Desnoyers a961e40917 membarrier: Provide register expedited private command ... This introduces a "register private expedited" membarrier command which allows eventual removal of important memory barrier constraints on the scheduler fast-paths. It changes how the "private expedited" membarrier command (new to 4.14) is used from user-space. This new command allows processes to register their intent to use the private expedited command. This affects how the expedited private command introduced in 4.14-rc is meant to be used, and should be merged before 4.14 final. Processes are now required to register before using MEMBARRIER_CMD_PRIVATE_EXPEDITED, otherwise that command returns EPERM. This fixes a problem that arose when designing requested extensions to sys_membarrier() to allow JITs to efficiently flush old code from instruction caches. Several potential algorithms are much less painful if the user register intent to use this functionality early on, for example, before the process spawns the second thread. Registering at this time removes the need to interrupt each and every thread in that process at the first expedited sys_membarrier() system call. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2017-10-19 22:13:40 -04:00
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autogroup.h
clock.h	sched/clock: Use late_initcall() instead of sched_init_smp()	2017-05-15 10:15:21 +02:00
coredump.h	mm: make PR_SET_THP_DISABLE immediately active	2017-07-10 16:32:31 -07:00
cpufreq.h
cputime.h
deadline.h
debug.h	sched/debug: Use task_pid_nr_ns in /proc/$pid/sched	2017-08-10 12:18:19 +02:00
hotplug.h
idle.h
init.h	sched/headers: Remove <linux/sched.h> from <linux/sched/init.h>	2017-03-03 01:45:38 +01:00
jobctl.h
loadavg.h
mm.h	membarrier: Provide register expedited private command	2017-10-19 22:13:40 -04:00
nohz.h	MAINTAINERS: Add Frederic Weisbecker as nohz/dyntics maintainer	2017-07-05 16:26:37 +02:00
numa_balancing.h
prio.h
rt.h	sched/rtmutex: Refactor rt_mutex_setprio()	2017-04-04 11:44:06 +02:00
signal.h	randstruct: Mark various structs for randomization	2017-06-30 12:00:51 -07:00
stat.h
sysctl.h
task_stack.h
task.h	sched/core: Remove unnecessary initialization init_idle_bootup_task()	2017-08-10 12:18:18 +02:00
topology.h	sched/core: Fix wake_affine() performance regression	2017-10-10 10:14:02 +02:00
user.h	sock: ulimit on MSG_ZEROCOPY pages	2017-08-03 21:37:30 -07:00
wake_q.h
xacct.h