Commit 9a45da92 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull RCU updates from Ingo Molnar:

 - Support for "N" as alias for last bit in bitmap parsing library (eg
   using syntax like "nohz_full=2-N")

 - kvfree_rcu updates

 - mm_dump_obj() updates. (One of these is to mm, but was suggested by
   Andrew Morton.)

 - RCU callback offloading update

 - Polling RCU grace-period interfaces

 - Realtime-related RCU updates

 - Tasks-RCU updates

 - Torture-test updates

 - Torture-test scripting updates

 - Miscellaneous fixes

* tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits)
  rcutorture: Test start_poll_synchronize_rcu() and poll_state_synchronize_rcu()
  rcu: Provide polling interfaces for Tiny RCU grace periods
  torture: Fix kvm.sh --datestamp regex check
  torture: Consolidate qemu-cmd duration editing into kvm-transform.sh
  torture: Print proper vmlinux path for kvm-again.sh runs
  torture: Make TORTURE_TRUST_MAKE available in kvm-again.sh environment
  torture: Make kvm-transform.sh update jitter commands
  torture: Add --duration argument to kvm-again.sh
  torture: Add kvm-again.sh to rerun a previous torture-test
  torture: Create a "batches" file for build reuse
  torture: De-capitalize TORTURE_SUITE
  torture: Make upper-case-only no-dot no-slash scenario names official
  torture: Rename SRCU-t and SRCU-u to avoid lowercase characters
  torture: Remove no-mpstat error message
  torture: Record kvm-test-1-run.sh and kvm-test-1-run-qemu.sh PIDs
  torture: Record jitter start/stop commands
  torture: Extract kvm-test-1-run-qemu.sh from kvm-test-1-run.sh
  torture: Record TORTURE_KCONFIG_GDB_ARG in qemu-cmd
  torture: Abstract jitter.sh start/stop into scripts
  rcu: Provide polling interfaces for Tree RCU grace periods
  ...
parents 68a32ba1 120b566d

Documentation/RCU/RTFP.txt

+1 −1
Original line number Diff line number Diff line
@@ -847,7 +847,7 @@ Symposium on Distributed Computing} 
	'It's entirely possible that the current user could be replaced

	by RCU and/or seqlocks, and we could get rid of brlocks entirely.'

	.

	Steve Hemminger responds by replacing them with RCU.

	Stephen Hemminger responds by replacing them with RCU.

}

}

Documentation/admin-guide/kernel-parameters.rst

+7 −0
Original line number Diff line number Diff line
@@ -68,6 +68,13 @@ For example one can add to the command line following parameter: 


where the final item represents CPUs 100,101,125,126,150,151,...



The value "N" can be used to represent the numerically last CPU on the system,

i.e "foo_cpus=16-N" would be equivalent to "16-31" on a 32 core system.



Keep in mind that "N" is dynamic, so if system changes cause the bitmap width

to change, such as less cores in the CPU list, then N and any ranges using N

will also change.  Use the same on a small 4 core system, and "16-N" becomes

"16-3" and now the same boot input will be flagged as invalid (start > end).





This document may not be entirely up to date and comprehensive. The command

Documentation/admin-guide/kernel-parameters.txt

+13 −3
Original line number Diff line number Diff line
@@ -4077,9 +4077,7 @@ 
				see CONFIG_RAS_CEC help text.



	rcu_nocbs=	[KNL]

			The argument is a cpu list, as described above,

			except that the string "all" can be used to

			specify every CPU on the system.

			The argument is a cpu list, as described above.



			In kernels built with CONFIG_RCU_NOCB_CPU=y, set

			the specified list of CPUs to be no-callback CPUs.
@@ -4268,6 +4266,18 @@ 
	rcuscale.kfree_rcu_test= [KNL]

			Set to measure performance of kfree_rcu() flooding.



	rcuscale.kfree_rcu_test_double= [KNL]

			Test the double-argument variant of kfree_rcu().

			If this parameter has the same value as

			rcuscale.kfree_rcu_test_single, both the single-

			and double-argument variants are tested.



	rcuscale.kfree_rcu_test_single= [KNL]

			Test the single-argument variant of kfree_rcu().

			If this parameter has the same value as

			rcuscale.kfree_rcu_test_double, both the single-

			and double-argument variants are tested.



	rcuscale.kfree_nthreads= [KNL]

			The number of threads running loops of kfree_rcu().

include/linux/mm.h

+4 −0
Original line number Diff line number Diff line
@@ -3180,7 +3180,11 @@ unsigned long wp_shared_mapping_range(struct address_space *mapping, 


extern int sysctl_nr_trim_pages;



#ifdef CONFIG_PRINTK

void mem_dump_obj(void *object);

#else

static inline void mem_dump_obj(void *object) {}

#endif



#endif /* __KERNEL__ */

#endif /* _LINUX_MM_H */

include/linux/rcu_segcblist.h

+4 −3
Original line number Diff line number Diff line
@@ -109,7 +109,7 @@ struct rcu_cblist { 
 *  |                           SEGCBLIST_KTHREAD_GP                           |

 *  |                                                                          |

 *  |   Kthreads handle callbacks holding nocb_lock, local rcu_core() stops    |

 *  |   handling callbacks.                                                    |

 *  |   handling callbacks. Enable bypass queueing.                            |

 *  ----------------------------------------------------------------------------

 */
@@ -125,7 +125,7 @@ struct rcu_cblist { 
 *  |                           SEGCBLIST_KTHREAD_GP                           |

 *  |                                                                          |

 *  |   CB/GP kthreads handle callbacks holding nocb_lock, local rcu_core()    |

 *  |   ignores callbacks.                                                     |

 *  |   ignores callbacks. Bypass enqueue is enabled.                          |

 *  ----------------------------------------------------------------------------

 *                                      |

 *                                      v
@@ -134,7 +134,8 @@ struct rcu_cblist { 
 *  |                           SEGCBLIST_KTHREAD_GP                           |

 *  |                                                                          |

 *  |   CB/GP kthreads and local rcu_core() handle callbacks concurrently      |

 *  |   holding nocb_lock. Wake up CB and GP kthreads if necessary.            |

 *  |   holding nocb_lock. Wake up CB and GP kthreads if necessary. Disable    |

 *  |   bypass enqueue.                                                        |

 *  ----------------------------------------------------------------------------

 *                                      |

 *                                      v