- 09 Jul, 2014 18 commits
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Paul E. McKenney authored
Merge branches 'doc.2014.07.08a', 'fixes.2014.07.09a', 'maintainers.2014.07.08b', 'nocbs.2014.07.07a' and 'torture.2014.07.07a' into HEAD doc.2014.07.08a: Documentation updates. fixes.2014.07.09a: Miscellaneous fixes. maintainers.2014.07.08b: Maintainership updates. nocbs.2014.07.07a: Callback-offloading fixes. torture.2014.07.07a: Torture-test updates.
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Pranith Kumar authored
This commit annotates rcu_report_unblock_qs_rnp() in order to fix the following sparse warning: kernel/rcu/tree_plugin.h:990:13: warning: context imbalance in 'rcu_report_unblock_qs_rnp' - unexpected unlock Signed-off-by:
Pranith Kumar <bobby.prani@gmail.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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Pranith Kumar authored
This commit annotates rcu_initiate_boost() fixes the following sparse warning: kernel/rcu/tree_plugin.h:1494:13: warning: context imbalance in 'rcu_initiate_boost' - unexpected unlock Signed-off-by:
Pranith Kumar <bobby.prani@gmail.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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Paul E. McKenney authored
The __rcu_reclaim() function returned 0/1, which is not proper for a function of type bool. This commit therefore converts to false/true. Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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Paul E. McKenney authored
The CONFIG_PROVE_RCU_DELAY Kconfig parameter doesn't appear to be very effective at finding race conditions, so this commit removes it. Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> [ paulmck: Remove definition and uses as noted by Paul Bolle. ]
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Shan Wei authored
The __this_cpu_read() function produces better code than does per_cpu_ptr() on both ARM and x86. For example, gcc (Ubuntu/Linaro 4.7.3-12ubuntu1) 4.7.3 produces the following: ARMv7 per_cpu_ptr(): force_quiescent_state: mov r3, sp @, bic r1, r3, #8128 @ tmp171,, ldr r2, .L98 @ tmp169, bic r1, r1, #63 @ tmp170, tmp171, ldr r3, [r0, #220] @ __ptr, rsp_6(D)->rda ldr r1, [r1, #20] @ D.35903_68->cpu, D.35903_68->cpu mov r6, r0 @ rsp, rsp ldr r2, [r2, r1, asl #2] @ tmp173, __per_cpu_offset add r3, r3, r2 @ tmp175, __ptr, tmp173 ldr r5, [r3, #12] @ rnp_old, D.29162_13->mynode ARMv7 __this_cpu_read(): force_quiescent_state: ldr r3, [r0, #220] @ rsp_7(D)->rda, rsp_7(D)->rda mov r6, r0 @ rsp, rsp add r3, r3, #12 @ __ptr, rsp_7(D)->rda, ldr r5, [r2, r3] @ rnp_old, *D.29176_13 Using gcc 4.8.2: x86_64 per_cpu_ptr(): movl %gs:cpu_number,%edx # cpu_number, pscr_ret__ movslq %edx, %rdx # pscr_ret__, pscr_ret__ movq __per_cpu_offset(,%rdx,8), %rdx # __per_cpu_offset, tmp93 movq %rdi, %r13 # rsp, rsp movq 1000(%rdi), %rax # rsp_9(D)->rda, __ptr movq 24(%rdx,%rax), %r12 # _15->mynode, rnp_old x86_64 __this_cpu_read(): movq %rdi, %r13 # rsp, rsp movq 1000(%rdi), %rax # rsp_9(D)->rda, rsp_9(D)->rda movq %gs:24(%rax),%r12 # _10->mynode, rnp_old Because this change produces significant benefits for these two very diverse architectures, this commit makes this change. Signed-off-by:
Shan Wei <davidshan@tencent.com> Acked-by:
Christoph Lameter <cl@linux.com> Signed-off-by:
Pranith Kumar <bobby.prani@gmail.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Josh Triplett <josh@joshtriplett.org> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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Paul E. McKenney authored
Although NMI-based stack dumps are in principle more accurate, they are also more likely to trigger deadlocks. This commit therefore replaces all uses of trigger_all_cpu_backtrace() with rcu_dump_cpu_stacks(), so that the CPU detecting an RCU CPU stall does the stack dumping. Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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Paul E. McKenney authored
Binding the grace-period kthreads to the timekeeping CPU resulted in significant performance decreases for some workloads. For more detail, see: https://lkml.org/lkml/2014/6/3/395 for benchmark numbers https://lkml.org/lkml/2014/6/4/218 for CPU statistics It turns out that it is necessary to bind the grace-period kthreads to the timekeeping CPU only when all but CPU 0 is a nohz_full CPU on the one hand or if CONFIG_NO_HZ_FULL_SYSIDLE=y on the other. In other cases, it suffices to bind the grace-period kthreads to the set of non-nohz_full CPUs. This commit therefore creates a tick_nohz_not_full_mask that is the complement of tick_nohz_full_mask, and then binds the grace-period kthread to the set of CPUs indicated by this new mask, which covers the CONFIG_NO_HZ_FULL_SYSIDLE=n case. The CONFIG_NO_HZ_FULL_SYSIDLE=y case still binds the grace-period kthreads to the timekeeping CPU. This commit also includes the tick_nohz_full_enabled() check suggested by Frederic Weisbecker. Reported-by:
Jet Chen <jet.chen@intel.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> [ paulmck: Created housekeeping_affine() and housekeeping_mask per fweisbec feedback. ]
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Paul E. McKenney authored
RCU priority boosting currently checks for boosting via a pointer in task_struct. However, this is not needed: As Oleg noted, if the rt_mutex is placed in the rcu_node instead of on the booster's stack, the boostee can simply check it see if it owns the lock. This commit makes this change, shrinking task_struct by one pointer and the kernel by thirteen lines. Suggested-by:
Oleg Nesterov <oleg@redhat.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Pranith Kumar authored
The rcu_start_future_gp() function checks the current rcu_node's ->gpnum and ->completed twice, once without ACCESS_ONCE() and once with it. Which is pointless because we hold that rcu_node's ->lock at that point. The intent was to check the current rcu_node structure and the root rcu_node structure, the latter locklessly with ACCESS_ONCE(). This commit therefore makes that change. The reason that it is safe to locklessly check the root rcu_nodes's ->gpnum and ->completed fields is that we hold the current rcu_node's ->lock, which constrains the root rcu_node's ability to change its ->gpnum and ->completed fields. Of course, if there is a single rcu_node structure, then rnp_root==rnp, and holding the lock prevents all changes. If there is more than one rcu_node structure, then the code updates the fields in the following order: 1. Increment rnp_root->gpnum to start new grace period. 2. Increment rnp->gpnum to initialize the current rcu_node, continuing initialization for the new grace period. 3. Increment rnp_root->completed to end the current grace period. 4. Increment rnp->completed to continue cleaning up after the old grace period. So there are four possible combinations of relative values of these four fields: N N N N: RCU idle, new grace period must be initiated. Although rnp_root->gpnum might be incremented immediately after we check, that will just result in unnecessary work. The grace period already started, and we try to start it. N+1 N N N: RCU grace period just started. No further change is possible because we hold rnp->lock, so the checks of rnp_root->gpnum and rnp_root->completed are stable. We know that our request for a future grace period will be seen during grace-period cleanup. N+1 N N+1 N: RCU grace period is ongoing. Because rnp->gpnum is different than rnp->completed, we won't even look at rnp_root->gpnum and rnp_root->completed, so the possible concurrent change to rnp_root->completed does not matter. We know that our request for a future grace period will be seen during grace-period cleanup, which cannot pass this rcu_node because we hold its ->lock. N+1 N+1 N+1 N: RCU grace period has ended, but not yet been cleaned up. Because rnp->gpnum is different than rnp->completed, we won't look at rnp_root->gpnum and rnp_root->completed, so the possible concurrent change to rnp_root->completed does not matter. We know that our request for a future grace period will be seen during grace-period cleanup, which cannot pass this rcu_node because we hold its ->lock. Therefore, despite initial appearances, the lockless check is safe. Signed-off-by:
Pranith Kumar <bobby.prani@gmail.com> [ paulmck: Update comment to say why the lockless check is safe. ] Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
The current approach to RCU priority boosting uses an rt_mutex strictly for its priority-boosting side effects. The rt_mutex_init_proxy_locked() function is used by the booster to initialize the lock as held by the boostee. The booster then uses rt_mutex_lock() to acquire this rt_mutex, which priority-boosts the boostee. When the boostee reaches the end of its outermost RCU read-side critical section, it checks a field in its task structure to see whether it has been boosted, and, if so, uses rt_mutex_unlock() to release the rt_mutex. The booster can then go on to boost the next task that is blocking the current RCU grace period. But reasonable implementations of rt_mutex_unlock() might result in the boostee referencing the rt_mutex's data after releasing it. But the booster might have re-initialized the rt_mutex between the time that the boostee released it and the time that it later referenced it. This is clearly asking for trouble, so this commit introduces a completion that forces the booster to wait until the boostee has completely finished with the rt_mutex, thus avoiding the case where the booster is re-initializing the rt_mutex before the last boostee's last reference to that rt_mutex. This of course does introduce some overhead, but the priority-boosting code paths are miles from any possible fastpath, and the overhead of executing the completion will normally be quite small compared to the overhead of priority boosting and deboosting, so this should be OK. Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
The m68k architecture aligns only to 16-bit boundaries, which can cause the align-to-32-bits check in __call_rcu() to trigger. Because there is currently no known potential need for more than one low-order bit, this commit loosens the check to 16-bit boundaries. Reported-by:
Greg Ungerer <gerg@uclinux.org> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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Paul E. McKenney authored
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>
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Paul E. McKenney authored
In kernels built with CONFIG_NO_HZ_FULL, tick_do_timer_cpu is constant once boot completes. Thus, there is no need to wrap it in ACCESS_ONCE() in code that is built only when CONFIG_NO_HZ_FULL. This commit therefore removes the redundant ACCESS_ONCE(). Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by:
Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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Fabian Frederick authored
Those two arrays are being passed to lockdep_init_map(), which expects const char *, and are stored in lockdep_map the same way. Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Fabian Frederick <fabf@skynet.be> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
The explicit local_irq_save() in __lock_task_sighand() is needed to avoid a potential deadlock condition, as noted in a841796f (signal: align __lock_task_sighand() irq disabling and RCU). However, someone reading the code might be forgiven for concluding that this separate local_irq_save() was completely unnecessary. This commit therefore adds a comment referencing the shiny new block comment on rcu_read_unlock(). Reported-by:
Oleg Nesterov <oleg@redhat.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by:
Oleg Nesterov <oleg@redhat.com> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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Paul E. McKenney authored
Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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Paul E. McKenney authored
Reported-by:
Oleg Nesterov <oleg@redhat.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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- 08 Jul, 2014 7 commits
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Joe Perches authored
We can now designate reviewers in the MAINTAINERS file with the new "R:" tag, so this commit teaches get_maintainers.pl to add their email addresses. Signed-off-by:
Joe Perches <joe@perches.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Joe Perches authored
Commit 51b1130e ("rcutorture: Abstract rcu_torture_random()") moved the file, so this commit updates the patterns. Signed-off-by:
Joe Perches <joe@perches.com> cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
Drop Dipankar Sarma at his request (https://lkml.org/lkml/2014/6/2/628), add Josh Triplett based on long-term review, contributions, and agreement to take on this role (https://lkml.org/lkml/2014/6/2/554). Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Josh Triplett <josh@joshtriplett.org>
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Paul E. McKenney authored
Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Josh Triplett <josh@joshtriplett.org> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com>
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Paul E. McKenney authored
It is possible to pair acquire and release barriers with other barriers, so this commit adds them to the list in the SMP barrier pairing section. Reported-by:
Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Tejun Heo <tj@kernel.org> Reviewed-by:
Josh Triplett <josh@joshtriplett.org> [ paulmck: Updated pairing discussion as suggested by Peter Zijlstra. ]
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Pranith Kumar authored
The kerneltrap.org site no longer works, so this commit updates it to a working reference, namely gmane. Signed-off-by:
Pranith Kumar <bobby.prani@gmail.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Josh Triplett <josh@joshtriplett.org>
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Paul E. McKenney authored
This commit adds an example demonstrating that if a wake_up() doesn't actually wake something up, no memory ordering is provided. Reported-by:
Peter Zijlstra <peterz@infradead.org> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Josh Triplett <josh@joshtriplett.org> Reviewed-by:
Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by:
Peter Zijlstra <peterz@infradead.org>
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- 07 Jul, 2014 5 commits
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Paul E. McKenney authored
Enabling NO_HZ_FULL currently has the side effect of enabling callback offloading on all CPUs. This results in lots of additional rcuo kthreads, and can also increase context switching and wakeups, even in cases where callback offloading is neither needed nor particularly desirable. This commit therefore enables callback offloading on a given CPU only if specifically requested at build time or boot time, or if that CPU has been specifically designated (again, either at build time or boot time) as a nohz_full CPU. Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
An 80-CPU system with a context-switch-heavy workload can require so many NOCB kthread wakeups that the RCU grace-period kthreads spend several tens of percent of a CPU just awakening things. This clearly will not scale well: If you add enough CPUs, the RCU grace-period kthreads would get behind, increasing grace-period latency. To avoid this problem, this commit divides the NOCB kthreads into leaders and followers, where the grace-period kthreads awaken the leaders each of whom in turn awakens its followers. By default, the number of groups of kthreads is the square root of the number of CPUs, but this default may be overridden using the rcutree.rcu_nocb_leader_stride boot parameter. This reduces the number of wakeups done per grace period by the RCU grace-period kthread by the square root of the number of CPUs, but of course by shifting those wakeups to the leaders. In addition, because the leaders do grace periods on behalf of their respective followers, the number of wakeups of the followers decreases by up to a factor of two. Instead of being awakened once when new callbacks arrive and again at the end of the grace period, the followers are awakened only at the end of the grace period. For a numerical example, in a 4096-CPU system, the grace-period kthread would awaken 64 leaders, each of which would awaken its 63 followers at the end of the grace period. This compares favorably with the 79 wakeups for the grace-period kthread on an 80-CPU system. Reported-by:
Rik van Riel <riel@redhat.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Kees Cook authored
Since the torture-test thread creation interface does not include format string arguments, this commit makes sure the name can never be accidentally processed as a format string. Signed-off-by:
Kees Cook <keescook@chromium.org> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Josh Triplett <josh@joshtriplett.org>
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Paul E. McKenney authored
Adding Steven Rostedt, Mathieu Desnoyers, and Lai Jiangshan as designated RCU reviewers based on recent emails: o https://lkml.org/lkml/2014/6/2/578 (Steven) o https://lkml.org/lkml/2014/6/2/621 (Mathieu) o https://lkml.org/lkml/2014/6/3/897 (Lai) Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Josh Triplett <josh@joshtriplett.org>
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Paul E. McKenney authored
A ksummit-discuss email thread looked at the difficulty recruiting and retaining reviewers. Paul Walmsley also noted the need for patch submitters to know who the key reviewers are and suggested adding an "R:" tag to the MAINTAINERS file to record this information on a per-subsystem basis. This commit does just that, and a subsequent commit tags the designated reviewer for the RCU-related subsystems. http://lists.linuxfoundation.org/pipermail/ksummit-discuss/2014-May/000830.htmlSuggested-by:
Paul Walmsley <paul@pwsan.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:
Josh Triplett <josh@joshtriplett.org> Acked-by:
Steven Rostedt <rostedt@goodmis.org>
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- 26 Jun, 2014 2 commits
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Paul E. McKenney authored
Currently the post-processing complains about the lack of rcutorture output when --buildonly is set and also emits misleading messages about kernels being started and finishing. This commit suppresses these complaints and messages. Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
The CFcommon file must now be present, which makes using the current scripts against old kernel versions cumbersome. This commit therefore makes the CFcommon file be optional, so that old kernel versions can be used with current torture scripts. Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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- 23 Jun, 2014 2 commits
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Paul E. McKenney authored
Commit ac1bea85 (Make cond_resched() report RCU quiescent states) fixed a problem where a CPU looping in the kernel with but one runnable task would give RCU CPU stall warnings, even if the in-kernel loop contained cond_resched() calls. Unfortunately, in so doing, it introduced performance regressions in Anton Blanchard's will-it-scale "open1" test. The problem appears to be not so much the increased cond_resched() path length as an increase in the rate at which grace periods complete, which increased per-update grace-period overhead. This commit takes a different approach to fixing this bug, mainly by moving the RCU-visible quiescent state from cond_resched() to rcu_note_context_switch(), and by further reducing the check to a simple non-zero test of a single per-CPU variable. However, this approach requires that the force-quiescent-state processing send resched IPIs to the offending CPUs. These will be sent only once the grace period has reached an age specified by the boot/sysfs parameter rcutree.jiffies_till_sched_qs, or once the grace period reaches an age halfway to the point at which RCU CPU stall warnings will be emitted, whichever comes first. Reported-by:
Dave Hansen <dave.hansen@intel.com> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Lameter <cl@gentwo.org> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Reviewed-by:
Josh Triplett <josh@joshtriplett.org> [ paulmck: Made rcu_momentary_dyntick_idle() as suggested by the ktest build robot. Also fixed smp_mb() comment as noted by Oleg Nesterov. ] Merge with e552592e (Reduce overhead of cond_resched() checks for RCU) Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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Paul E. McKenney authored
Currently, call_rcu() relies on implicit allocation and initialization for the debug-objects handling of RCU callbacks. If you hammer the kernel hard enough with Sasha's modified version of trinity, you can end up with the sl*b allocators recursing into themselves via this implicit call_rcu() allocation. This commit therefore exports the debug_init_rcu_head() and debug_rcu_head_free() functions, which permits the allocators to allocated and pre-initialize the debug-objects information, so that there no longer any need for call_rcu() to do that initialization, which in turn prevents the recursion into the memory allocators. Reported-by:
Sasha Levin <sasha.levin@oracle.com> Suggested-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by:
Thomas Gleixner <tglx@linutronix.de> Looks-good-to: Christoph Lameter <cl@linux.com>
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- 16 Jun, 2014 4 commits
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds authored
Pull networking fixes from David Miller: 1) Fix checksumming regressions, from Tom Herbert. 2) Undo unintentional permissions changes for SCTP rto_alpha and rto_beta sysfs knobs, from Denial Borkmann. 3) VXLAN, like other IP tunnels, should advertize it's encapsulation size using dev->needed_headroom instead of dev->hard_header_len. From Cong Wang. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: net: sctp: fix permissions for rto_alpha and rto_beta knobs vxlan: Checksum fixes net: add skb_pop_rcv_encapsulation udp: call __skb_checksum_complete when doing full checksum net: Fix save software checksum complete net: Fix GSO constants to match NETIF flags udp: ipv4: do not waste time in __udp4_lib_mcast_demux_lookup vxlan: use dev->needed_headroom instead of dev->hard_header_len MAINTAINERS: update cxgb4 maintainer
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git://git.linaro.org/people/mike.turquette/linuxLinus Torvalds authored
Pull more clock framework updates from Mike Turquette: "This contains the second half the of the clk changes for 3.16. They are simply fixes and code refactoring for the OMAP clock drivers. The sunxi clock driver changes include splitting out the one mega-driver into several smaller pieces and adding support for the A31 SoC clocks" * tag 'clk-for-linus-3.16-part2' of git://git.linaro.org/people/mike.turquette/linux: (25 commits) clk: sunxi: document PRCM clock compatible strings clk: sunxi: add PRCM (Power/Reset/Clock Management) clks support clk: sun6i: Protect SDRAM gating bit clk: sun6i: Protect CPU clock clk: sunxi: Rework clock protection code clk: sunxi: Move the GMAC clock to a file of its own clk: sunxi: Move the 24M oscillator to a file of its own clk: sunxi: Remove calls to clk_put clk: sunxi: document new A31 USB clock compatible clk: sunxi: Implement A31 USB clock ARM: dts: OMAP5/DRA7: use omap5-mpu-dpll-clock capable of dealing with higher frequencies CLK: TI: dpll: support OMAP5 MPU DPLL that need special handling for higher frequencies ARM: OMAP5+: dpll: support Duty Cycle Correction(DCC) CLK: TI: clk-54xx: Set the rate for dpll_abe_m2x2_ck CLK: TI: Driver for DRA7 ATL (Audio Tracking Logic) dt:/bindings: DRA7 ATL (Audio Tracking Logic) clock bindings ARM: dts: dra7xx-clocks: Correct name for atl clkin3 clock CLK: TI: gate: add composite interface clock to OMAP2 only build ARM: OMAP2: clock: add DT boot support for cpufreq_ck CLK: TI: OMAP2: add clock init support ...
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git://git.infradead.org/users/willy/linux-nvmeLinus Torvalds authored
Pull NVMe update from Matthew Wilcox: "Mostly bugfixes again for the NVMe driver. I'd like to call out the exported tracepoint in the block layer; I believe Keith has cleared this with Jens. We've had a few reports from people who're really pounding on NVMe devices at scale, hence the timeout changes (and new module parameters), hotplug cpu deadlock, tracepoints, and minor performance tweaks" [ Jens hadn't seen that tracepoint thing, but is ok with it - it will end up going away when mq conversion happens ] * git://git.infradead.org/users/willy/linux-nvme: (22 commits) NVMe: Fix START_STOP_UNIT Scsi->NVMe translation. NVMe: Use Log Page constants in SCSI emulation NVMe: Define Log Page constants NVMe: Fix hot cpu notification dead lock NVMe: Rename io_timeout to nvme_io_timeout NVMe: Use last bytes of f/w rev SCSI Inquiry NVMe: Adhere to request queue block accounting enable/disable NVMe: Fix nvme get/put queue semantics NVMe: Delete NVME_GET_FEAT_TEMP_THRESH NVMe: Make admin timeout a module parameter NVMe: Make iod bio timeout a parameter NVMe: Prevent possible NULL pointer dereference NVMe: Fix the buffer size passed in GetLogPage(CDW10.NUMD) NVMe: Update data structures for NVMe 1.2 NVMe: Enable BUILD_BUG_ON checks NVMe: Update namespace and controller identify structures to the 1.1a spec NVMe: Flush with data support NVMe: Configure support for block flush NVMe: Add tracepoints NVMe: Protect against badly formatted CQEs ...
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- 15 Jun, 2014 2 commits
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Daniel Borkmann authored
Commit 3fd091e7 ("[SCTP]: Remove multiple levels of msecs to jiffies conversions.") has silently changed permissions for rto_alpha and rto_beta knobs from 0644 to 0444. The purpose of this was to discourage users from tweaking rto_alpha and rto_beta knobs in production environments since they are key to correctly compute rtt/srtt. RFC4960 under section 6.3.1. RTO Calculation says regarding rto_alpha and rto_beta under rule C3 and C4: [...] C3) When a new RTT measurement R' is made, set RTTVAR <- (1 - RTO.Beta) * RTTVAR + RTO.Beta * |SRTT - R'| and SRTT <- (1 - RTO.Alpha) * SRTT + RTO.Alpha * R' Note: The value of SRTT used in the update to RTTVAR is its value before updating SRTT itself using the second assignment. After the computation, update RTO <- SRTT + 4 * RTTVAR. C4) When data is in flight and when allowed by rule C5 below, a new RTT measurement MUST be made each round trip. Furthermore, new RTT measurements SHOULD be made no more than once per round trip for a given destination transport address. There are two reasons for this recommendation: First, it appears that measuring more frequently often does not in practice yield any significant benefit [ALLMAN99]; second, if measurements are made more often, then the values of RTO.Alpha and RTO.Beta in rule C3 above should be adjusted so that SRTT and RTTVAR still adjust to changes at roughly the same rate (in terms of how many round trips it takes them to reflect new values) as they would if making only one measurement per round-trip and using RTO.Alpha and RTO.Beta as given in rule C3. However, the exact nature of these adjustments remains a research issue. [...] While it is discouraged to adjust rto_alpha and rto_beta and not further specified how to adjust them, the RFC also doesn't explicitly forbid it, but rather gives a RECOMMENDED default value (rto_alpha=3, rto_beta=2). We have a couple of users relying on the old permissions before they got changed. That said, if someone really has the urge to adjust them, we could allow it with a warning in the log. Fixes: 3fd091e7 ("[SCTP]: Remove multiple levels of msecs to jiffies conversions.") Signed-off-by:
Daniel Borkmann <dborkman@redhat.com> Cc: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
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David S. Miller authored
Tom Herbert says: ==================== Fixes related to some recent checksum modifications. - Fix GSO constants to match NETIF flags - Fix logic in saving checksum complete in __skb_checksum_complete - Call __skb_checksum_complete from UDP if we are checksumming over whole packet in order to save checksum. - Fixes to VXLAN to work correctly with checksum complete ==================== Signed-off-by:
David S. Miller <davem@davemloft.net>
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