Message	SHA1
rcu: Expand SRCU ->completed to 64 bits ... When rcutorture used only the low-order 32 bits of the grace-period number, it was not a problem for SRCU to use a 32-bit completed field. However, rcutorture now uses the full 64 bits on 64-bit systems, so this commit converts SRCU's ->completed field to unsigned long so as to provide 64 bits on 64-bit systems. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Paul E. McKenney   commited 2015-01-06 11:04:26 -08:00	a5c198f4f7
rcu: Eliminate read-modify-write ACCESS_ONCE() calls ... RCU contains code of the following forms: ACCESS_ONCE(x)++; ACCESS_ONCE(x) += y; ACCESS_ONCE(x) -= y; Now these constructs do operate correctly, but they really result in a pair of volatile accesses, one to do the load and another to do the store. This can be confusing, as the casual reader might well assume that (for example) gcc might generate a memory-to-memory add instruction for each of these three cases. In fact, gcc will do no such thing. Also, there is a good chance that the kernel will move to separate load and store variants of ACCESS_ONCE(), and constructs like the above could easily confuse both people and scripts attempting to make that sort of change. Finally, most of RCU's read-modify-write uses of ACCESS_ONCE() really only need the store to be volatile, so that the read-modify-write form might be misleading. This commit therefore changes the above forms in RCU so that each instance of ACCESS_ONCE() either does a load or a store, but not both. In a few cases, ACCESS_ONCE() was not critical, for example, for maintaining statisitics. In these cases, ACCESS_ONCE() has been dispensed with entirely. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Paul E. McKenney   commited 2014-07-09 09:14:49 -07:00	a792563bd4
rcu: Ensure kernel/rcu/rcu.h can be sourced/used stand-alone ... The kbuild test bot uncovered an implicit dependence on the trace header being present before rcu.h in ia64 allmodconfig that looks like this: In file included from kernel/ksysfs.c:22:0: kernel/rcu/rcu.h: In function '__rcu_reclaim': kernel/rcu/rcu.h:107:3: error: implicit declaration of function 'trace_rcu_invoke_kfree_callback' [-Werror=implicit-function-declaration] kernel/rcu/rcu.h:112:3: error: implicit declaration of function 'trace_rcu_invoke_callback' [-Werror=implicit-function-declaration] cc1: some warnings being treated as errors Looking at other rcu.h users, we can find that they all were sourcing the trace header in advance of rcu.h itself, as seen in the context of this diff. There were also some inconsistencies as to whether it was or wasn't sourced based on the parent tracing Kconfig. Rather than "fix" it at each use site, and have inconsistent use based on whether "#ifdef CONFIG_RCU_TRACE" was used or not, lets just source the trace header just once, in the actual consumer of it, which is rcu.h itself. We include it unconditionally, as build testing shows us that is a hard requirement for some files. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Paul Gortmaker   authored and   Paul E. McKenney   commited 2014-02-26 06:35:18 -08:00	5cb5c6e18f
rcu: Move SRCU grace period work to power efficient workqueue ... For better use of CPU idle time, allow the scheduler to select the CPU on which the SRCU grace period work would be scheduled. This improves idle residency time and conserves power. This functionality is enabled when CONFIG_WQ_POWER_EFFICIENT is selected. Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Dipankar Sarma <dipankar@in.ibm.com> Signed-off-by: Shaibal Dutta <shaibal.dutta@broadcom.com> [zoran.markovic@linaro.org: Rebased to latest kernel version. Added commit message. Fixed code alignment.] Signed-off-by: Zoran Markovic <zoran.markovic@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Shaibal Dutta   authored and   Paul E. McKenney   commited 2014-02-17 15:02:14 -08:00	ae1670339c
rcu: Stop tracking FSF's postal address ... All of the RCU source files have the usual GPL header, which contains a long-obsolete postal address for FSF. To avoid the need to track the FSF office's movements, this commit substitutes the URL where GPL may be found. Reported-by: Greg KH <gregkh@linuxfoundation.org> Reported-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Paul E. McKenney   commited 2014-02-17 15:01:37 -08:00	87de1cfdc5
rcu: Improve SRCU's grace-period comments ... This commit documents the memory-barrier guarantees provided by synchronize_srcu() and call_srcu(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Paul E. McKenney   commited 2013-12-09 15:12:38 -08:00	bc72d962d6
rcu: Fix srcu_barrier() docbook header ... The srcu_barrier() docbook header left out the "sp" argument, so this commit adds that argument's docbook text. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Paul E. McKenney   commited 2013-12-03 10:10:19 -08:00	4461212aa0
rcu: Move RCU-related source code to kernel/rcu directory ... Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Ingo Molnar <mingo@kernel.org> Paul E. McKenney   commited 2013-10-15 12:53:31 -07:00	4102adab91

Renamed from kernel/srcu.c (Browse further)