- 01 3月, 2008 2 次提交
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由 Paul E. McKenney 提交于
This fixes a oops encountered when doing hibernate/resume in presence of PREEMPT_RCU. The problem was that the code failed to disable preemption when accessing a per-CPU variable. This is OK when called from code that already has preemption disabled, but such is not the case from the suspend/resume code path. Reported-by: NDave Young <hidave.darkstar@gmail.com> Tested-by: NDave Young <hidave.darkstar@gmail.com> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Steven Rostedt 提交于
The PREEMPT-RCU can get stuck if a CPU goes idle and NO_HZ is set. The idle CPU will not progress the RCU through its grace period and a synchronize_rcu my get stuck. Without this patch I have a box that will not boot when PREEMPT_RCU and NO_HZ are set. That same box boots fine with this patch. This patch comes from the -rt kernel where it has been tested for several months. Signed-off-by: NSteven Rostedt <srostedt@redhat.com> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 26 1月, 2008 2 次提交
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由 Paul E. McKenney 提交于
This patch allows preemptible RCU to tolerate CPU-hotplug operations. It accomplishes this by maintaining a local copy of a map of online CPUs, which it accesses under its own lock. Signed-off-by: NGautham R Shenoy <ego@in.ibm.com> Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: NSteven Rostedt <srostedt@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Paul E. McKenney 提交于
This patch implements a new version of RCU which allows its read-side critical sections to be preempted. It uses a set of counter pairs to keep track of the read-side critical sections and flips them when all tasks exit read-side critical section. The details of this implementation can be found in this paper - http://www.rdrop.com/users/paulmck/RCU/OLSrtRCU.2006.08.11a.pdf and the article- http://lwn.net/Articles/253651/ This patch was developed as a part of the -rt kernel development and meant to provide better latencies when read-side critical sections of RCU don't disable preemption. As a consequence of keeping track of RCU readers, the readers have a slight overhead (optimizations in the paper). This implementation co-exists with the "classic" RCU implementations and can be switched to at compiler. Also includes RCU tracing summarized in debugfs. [ akpm@linux-foundation.org: build fixes on non-preempt architectures ] Signed-off-by: NGautham R Shenoy <ego@in.ibm.com> Signed-off-by: NDipankar Sarma <dipankar@in.ibm.com> Signed-off-by: NPaul E. McKenney <paulmck@us.ibm.com> Reviewed-by: NSteven Rostedt <srostedt@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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