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Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull scheduler updates from Ingo Molnar:

 - membarrier updates (Mathieu Desnoyers)

 - SMP balancing optimizations (Mel Gorman)

 - stats update optimizations (Peter Zijlstra)

 - RT scheduler race fixes (Steven Rostedt)

 - misc fixes and updates

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Use a recently used CPU as an idle candidate and the basis for SIS
  sched/fair: Do not migrate if the prev_cpu is idle
  sched/fair: Restructure wake_affine*() to return a CPU id
  sched/fair: Remove unnecessary parameters from wake_affine_idle()
  sched/rt: Make update_curr_rt() more accurate
  sched/rt: Up the root domain ref count when passing it around via IPIs
  sched/rt: Use container_of() to get root domain in rto_push_irq_work_func()
  sched/core: Optimize update_stats_*()
  sched/core: Optimize ttwu_stat()
  membarrier/selftest: Test private expedited sync core command
  membarrier/arm64: Provide core serializing command
  membarrier/x86: Provide core serializing command
  membarrier: Provide core serializing command, *_SYNC_CORE
  lockin/x86: Implement sync_core_before_usermode()
  locking: Introduce sync_core_before_usermode()
  membarrier/selftest: Test global expedited command
  membarrier: Provide GLOBAL_EXPEDITED command
  membarrier: Document scheduler barrier requirements
  powerpc, membarrier: Skip memory barrier in switch_mm()
  membarrier/selftest: Test private expedited command
This commit is contained in:
Linus Torvalds
2018-02-06 19:57:31 -08:00
parent 4b0dda4f86 8284507916
commit ab2d92ad88
25 changed files with 750 additions and 127 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/uapi/linux/membarrier.h
+66 -8
View File
@@ -31,7 +31,7 @@
* enum membarrier_cmd - membarrier system call command
* @MEMBARRIER_CMD_QUERY: Query the set of supported commands. It returns
* a bitmask of valid commands.
* @MEMBARRIER_CMD_SHARED: Execute a memory barrier on all running threads.
* @MEMBARRIER_CMD_GLOBAL: Execute a memory barrier on all running threads.
* Upon return from system call, the caller thread
* is ensured that all running threads have passed
* through a state where all memory accesses to
@@ -40,6 +40,28 @@
* (non-running threads are de facto in such a
* state). This covers threads from all processes
* running on the system. This command returns 0.
* @MEMBARRIER_CMD_GLOBAL_EXPEDITED:
* Execute a memory barrier on all running threads
* of all processes which previously registered
* with MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED.
* Upon return from system call, the caller thread
* is ensured that all running threads have passed
* through a state where all memory accesses to
* user-space addresses match program order between
* entry to and return from the system call
* (non-running threads are de facto in such a
* state). This only covers threads from processes
* which registered with
* MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED.
* This command returns 0. Given that
* registration is about the intent to receive
* the barriers, it is valid to invoke
* MEMBARRIER_CMD_GLOBAL_EXPEDITED from a
* non-registered process.
* @MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED:
* Register the process intent to receive
* MEMBARRIER_CMD_GLOBAL_EXPEDITED memory
* barriers. Always returns 0.
* @MEMBARRIER_CMD_PRIVATE_EXPEDITED:
* Execute a memory barrier on each running
* thread belonging to the same process as the current
@@ -51,7 +73,7 @@
* to and return from the system call
* (non-running threads are de facto in such a
* state). This only covers threads from the
* same processes as the caller thread. This
* same process as the caller thread. This
* command returns 0 on success. The
* "expedited" commands complete faster than
* the non-expedited ones, they never block,
@@ -64,18 +86,54 @@
* Register the process intent to use
* MEMBARRIER_CMD_PRIVATE_EXPEDITED. Always
* returns 0.
* @MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE:
* In addition to provide memory ordering
* guarantees described in
* MEMBARRIER_CMD_PRIVATE_EXPEDITED, ensure
* the caller thread, upon return from system
* call, that all its running threads siblings
* have executed a core serializing
* instruction. (architectures are required to
* guarantee that non-running threads issue
* core serializing instructions before they
* resume user-space execution). This only
* covers threads from the same process as the
* caller thread. This command returns 0 on
* success. The "expedited" commands complete
* faster than the non-expedited ones, they
* never block, but have the downside of
* causing extra overhead. If this command is
* not implemented by an architecture, -EINVAL
* is returned. A process needs to register its
* intent to use the private expedited sync
* core command prior to using it, otherwise
* this command returns -EPERM.
* @MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE:
* Register the process intent to use
* MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE.
* If this command is not implemented by an
* architecture, -EINVAL is returned.
* Returns 0 on success.
* @MEMBARRIER_CMD_SHARED:
* Alias to MEMBARRIER_CMD_GLOBAL. Provided for
* header backward compatibility.
*
* Command to be passed to the membarrier system call. The commands need to
* be a single bit each, except for MEMBARRIER_CMD_QUERY which is assigned to
* the value 0.
*/
enum membarrier_cmd {
MEMBARRIER_CMD_QUERY = 0,
MEMBARRIER_CMD_SHARED = (1 << 0),
/* reserved for MEMBARRIER_CMD_SHARED_EXPEDITED (1 << 1) */
/* reserved for MEMBARRIER_CMD_PRIVATE (1 << 2) */
MEMBARRIER_CMD_PRIVATE_EXPEDITED = (1 << 3),
MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED = (1 << 4),
MEMBARRIER_CMD_QUERY = 0,
MEMBARRIER_CMD_GLOBAL = (1 << 0),
MEMBARRIER_CMD_GLOBAL_EXPEDITED = (1 << 1),
MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED = (1 << 2),
MEMBARRIER_CMD_PRIVATE_EXPEDITED = (1 << 3),
MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED = (1 << 4),
MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE = (1 << 5),
MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE = (1 << 6),
/* Alias for header backward compatibility. */
MEMBARRIER_CMD_SHARED = MEMBARRIER_CMD_GLOBAL,
};
#endif /* _UAPI_LINUX_MEMBARRIER_H */