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2009-11-23perf_events: Disable events when we detach themPeter Zijlstra
If we leave the event in STATE_INACTIVE, any read of the event after the detach will increase the running count but not the enabled count and cause funny scaling artefacts. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20091123103819.689055515@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-23perf_events: Fix style nitsPeter Zijlstra
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20091123103819.613427378@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-23perf_events: Undo copy/paste damagePeter Zijlstra
We had two almost identical functions, avoid the duplication. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <20091123103819.537537928@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-23perf_events: Optimize the swcounter hotpathIngo Molnar
The structure init creates a bit memcpy, which shows up big time in perf annotate output: : ffffffff810a859d <__perf_sw_event>: 1.68 : ffffffff810a859d: 55 push %rbp 1.69 : ffffffff810a859e: 41 89 fa mov %edi,%r10d 0.01 : ffffffff810a85a1: 49 89 c9 mov %rcx,%r9 0.00 : ffffffff810a85a4: 31 c0 xor %eax,%eax 1.71 : ffffffff810a85a6: b9 16 00 00 00 mov $0x16,%ecx 0.00 : ffffffff810a85ab: 48 89 e5 mov %rsp,%rbp 0.00 : ffffffff810a85ae: 48 83 ec 60 sub $0x60,%rsp 1.52 : ffffffff810a85b2: 48 8d 7d a0 lea -0x60(%rbp),%rdi 85.20 : ffffffff810a85b6: f3 ab rep stos %eax,%es:(%rdi) None of the callees depends on the structure being pre-initialized, so only initialize ->addr. This gets rid of the memcpy overhead. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-23tracing, function tracer: Clean up strstrip() usageIngo Molnar
Clean up strstrip() usage - which also addresses this build warning: kernel/trace/ftrace.c: In function 'ftrace_pid_write': kernel/trace/ftrace.c:3004: warning: ignoring return value of 'strstrip', declared with attribute warn_unused_result Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-23perf events: Do not generate function trace entries in perf codeIngo Molnar
Decreases perf overhead when function tracing is enabled, by about 50%. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-23ring-buffer benchmark: Run producer/consumer threads at nice +19Ingo Molnar
The ring-buffer benchmark threads run on nice 0 by default, using up a lot of CPU time and slowing down the system: PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1024 root 20 0 0 0 0 D 95.3 0.0 4:01.67 rb_producer 1023 root 20 0 0 0 0 R 93.5 0.0 2:54.33 rb_consumer 21569 mingo 40 0 14852 1048 772 R 3.6 0.1 0:00.05 top 1 root 40 0 4080 928 668 S 0.0 0.0 0:23.98 init Renice them to +19 to make them less intrusive. Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-22rcu: Re-arrange code to reduce #ifdef painPaul E. McKenney
Remove #ifdefs from kernel/rcupdate.c and include/linux/rcupdate.h by moving code to include/linux/rcutiny.h, include/linux/rcutree.h, and kernel/rcutree.c. Also remove some definitions that are no longer used. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1258908830885-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-22rcu: Eliminate unneeded function wrappingPaul E. McKenney
The functions rcu_init() is a wrapper for __rcu_init(), and also sets up the CPU-hotplug notifier for rcu_barrier_cpu_hotplug(). But TINY_RCU doesn't need CPU-hotplug notification, and the rcu_barrier_cpu_hotplug() is a simple wrapper for rcu_cpu_notify(). So push rcu_init() out to kernel/rcutree.c and kernel/rcutiny.c and get rid of the wrapper function rcu_barrier_cpu_hotplug(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12589088302320-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-22rcu: Fix grace-period-stall bug on large systems with CPU hotplugPaul E. McKenney
When the last CPU of a given leaf rcu_node structure goes offline, all of the tasks queued on that leaf rcu_node structure (due to having blocked in their current RCU read-side critical sections) are requeued onto the root rcu_node structure. This requeuing is carried out by rcu_preempt_offline_tasks(). However, it is possible that these queued tasks are the only thing preventing the leaf rcu_node structure from reporting a quiescent state up the rcu_node hierarchy. Unfortunately, the old code would fail to do this reporting, resulting in a grace-period stall given the following sequence of events: 1. Kernel built for more than 32 CPUs on 32-bit systems or for more than 64 CPUs on 64-bit systems, so that there is more than one rcu_node structure. (Or CONFIG_RCU_FANOUT is artificially set to a number smaller than CONFIG_NR_CPUS.) 2. The kernel is built with CONFIG_TREE_PREEMPT_RCU. 3. A task running on a CPU associated with a given leaf rcu_node structure blocks while in an RCU read-side critical section -and- that CPU has not yet passed through a quiescent state for the current RCU grace period. This will cause the task to be queued on the leaf rcu_node's blocked_tasks[] array, in particular, on the element of this array corresponding to the current grace period. 4. Each of the remaining CPUs corresponding to this same leaf rcu_node structure pass through a quiescent state. However, the task is still in its RCU read-side critical section, so these quiescent states cannot be reported further up the rcu_node hierarchy. Nevertheless, all bits in the leaf rcu_node structure's ->qsmask field are now zero. 5. Each of the remaining CPUs go offline. (The events in step #4 and #5 can happen in any order as long as each CPU passes through a quiescent state before going offline.) 6. When the last CPU goes offline, __rcu_offline_cpu() will invoke rcu_preempt_offline_tasks(), which will move the task to the root rcu_node structure, but without reporting a quiescent state up the rcu_node hierarchy (and this failure to report a quiescent state is the bug). But because this leaf rcu_node structure's ->qsmask field is already zero and its ->block_tasks[] entries are all empty, force_quiescent_state() will skip this rcu_node structure. Therefore, grace periods are now hung. This patch abstracts some code out of rcu_read_unlock_special(), calling the result task_quiet() by analogy with cpu_quiet(), and invokes task_quiet() from both rcu_read_lock_special() and __rcu_offline_cpu(). Invoking task_quiet() from __rcu_offline_cpu() reports the quiescent state up the rcu_node hierarchy, fixing the bug. This ends up requiring a separate lock_class_key per level of the rcu_node hierarchy, which this patch also provides. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <12589088301770-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-22perf_events: Fix modular buildIngo Molnar
Fix: ERROR: "perf_swevent_put_recursion_context" [fs/ext4/ext4.ko] undefined! ERROR: "perf_swevent_get_recursion_context" [fs/ext4/ext4.ko] undefined! Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Jason Baron <jbaron@redhat.com> LKML-Reference: <1258864015-10579-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-22perf_event: Remove redundant zero fillMárton Németh
The buffer is first zeroed out by memset(). Then strncpy() is used to fill the content. The strncpy() function also pads the string till the end of the specified length, which is redundant. The strncpy() does not ensures that the string will be properly closed with 0. Use strlcpy() instead. The semantic match that finds this kind of pattern is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression buffer; expression size; expression str; @@ memset(buffer, 0, size); ... - strncpy( + strlcpy( buffer, str, sizeof(buffer) ); @@ expression buffer; expression size; expression str; @@ memset(&buffer, 0, size); ... - strncpy( + strlcpy( &buffer, str, sizeof(buffer)); @@ expression buffer; identifier field; expression size; expression str; @@ memset(buffer, 0, size); ... - strncpy( + strlcpy( buffer->field, str, sizeof(buffer->field) ); @@ expression buffer; identifier field; expression size; expression str; @@ memset(&buffer, 0, size); ... - strncpy( + strlcpy( buffer.field, str, sizeof(buffer.field)); // </smpl> On strncpy() vs strlcpy() see http://www.gratisoft.us/todd/papers/strlcpy.html . Signed-off-by: Márton Németh <nm127@freemail.hu> Cc: Julia Lawall <julia@diku.dk> Cc: cocci@diku.dk Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <4B086547.5040100@freemail.hu> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-22hw-breakpoints: Remove x86 specific headers from core fileFrederic Weisbecker
Remove asm/processor.h and asm/debugreg.h as these headers are not used anymore in the hw-breakpoints core file. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Prasad <prasad@linux.vnet.ibm.com> LKML-Reference: <1258863695-10464-3-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-22tracing: Forget about the NMI buffer for syscall eventsFrederic Weisbecker
We are never in an NMI context when we commit a syscall trace to perf. So just forget about the nmi buffer there. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jason Baron <jbaron@redhat.com> LKML-Reference: <1258863695-10464-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-22tracing: Use the perf recursion protection from trace eventFrederic Weisbecker
When we commit a trace to perf, we first check if we are recursing in the same buffer so that we don't mess-up the buffer with a recursing trace. But later on, we do the same check from perf to avoid commit recursion. The recursion check is desired early before we touch the buffer but we want to do this check only once. Then export the recursion protection from perf and use it from the trace events before submitting a trace. v2: Put appropriate Reported-by tag Reported-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Masami Hiramatsu <mhiramat@redhat.com> Cc: Jason Baron <jbaron@redhat.com> LKML-Reference: <1258864015-10579-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf_events: Fix default watermark calculationStephane Eranian
This patch fixes the default watermark value for the sampling buffer. With the existing calculation (watermark = max(PAGE_SIZE, max_size / 2)), no notification was ever received when the buffer was exactly 1 page. This was because you would never cross the threshold (there is no partial samples). In certain configuration, there was no possibilty detecting the problem because there was not enough space left to store the LOST record.In fact, there may be a more generic problem here. The kernel should ensure that there is alaways enough space to store one LOST record. This patch sets the default watermark to half the buffer size. With such limit, we are guaranteed to get a notification even with a single page buffer assuming no sample is bigger than a page. Signed-off-by: Stephane Eranian <eranian@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212509.344964101@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <1256302576-6169-1-git-send-email-eranian@gmail.com>
2009-11-21perf: Fix locking for PERF_FORMAT_GROUPPeter Zijlstra
We should hold event->child_mutex when iterating the inherited counters, we should hold ctx->mutex when iterating siblings. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212509.251030114@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Fix event scaling for inherited countersPeter Zijlstra
Properly account the full hierarchy of counters for both the count (we already did so) and the scale times (new). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212509.153379276@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Fix time lockingPeter Zijlstra
Most sites updating ctx->time and event times do so under ctx->lock, make sure they all do. This was made possible by removing the __perf_event_read() call from __perf_event_sync_stat(), which already had this lock taken. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212509.102316434@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Simplify __perf_event_readPeter Zijlstra
cpuctx is always active, task context is always active for current the previous condition verifies that if its a task context its for current, hence we can assume ctx->is_active. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212509.000272254@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Simplify __perf_event_sync_statPeter Zijlstra
Removes constraints from __perf_event_read() by leaving it with a single callsite; this callsite had ctx->lock held, the other one does not. Removes some superfluous code from __perf_event_sync_stat(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212508.918544317@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Optimize __perf_event_read()Peter Zijlstra
Both callers actually have IRQs disabled, no need doing so again. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212508.863685796@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Optimize perf_event_task_sched_outPeter Zijlstra
Remove an update_context_time() call from the perf_event_task_sched_out() path and into the branch its needed. The call was both superfluous, because __perf_event_sched_out() already does it, and wrong, because it was done without holding ctx->lock. Place it in perf_event_sync_stat(), which is the only place it is needed and which does already hold ctx->lock. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212508.779516394@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Fix PERF_FORMAT_GROUP scale infoPeter Zijlstra
As Corey reported, the total_enabled and total_running times could occasionally be 0, even though there were events counted. It turns out this is because we record the times before reading the counter while the latter updates the times. This patch corrects that. While looking at this code I found that there is a lot of locking iffyness around, the following patches correct most of that. Reported-by: Corey Ashford <cjashfor@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212508.685559857@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Optimize perf_event_mmap_ctx()Peter Zijlstra
Remove a rcu_read_{,un}lock() pair and a few conditionals. We can remove the rcu_read_lock() by increasing the scope of one in the calling function. We can do away with the system_state check if the machine still boots after this patch (seems to be the case). We can do away with the list_empty() check because the bare list_for_each_entry_rcu() reduces to that now that we've removed everything else. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212508.606459548@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Optimize perf_event_comm_ctx()Peter Zijlstra
Remove a rcu_read_{,un}lock() pair and a few conditionals. We can remove the rcu_read_lock() by increasing the scope of one in the calling function. We can do away with the system_state check if the machine still boots after this patch (seems to be the case). We can do away with the list_empty() check because the bare list_for_each_entry_rcu() reduces to that now that we've removed everything else. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212508.527608793@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Optimize perf_event_task_ctx()Peter Zijlstra
Remove a rcu_read_{,un}lock() pair and a few conditionals. We can remove the rcu_read_lock() by increasing the scope of one in the calling function. We can do away with the system_state check if the machine still boots after this patch (seems to be the case). We can do away with the list_empty() check because the bare list_for_each_entry_rcu() reduces to that now that we've removed everything else. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212508.452227115@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Optimize perf_swevent_ctx_event()Peter Zijlstra
Remove a rcu_read_{,un}lock() pair and a few conditionals. We can remove the rcu_read_lock() by increasing the scope of one in the calling function. We can do away with the system_state check if the machine still boots after this patch (seems to be the case). We can do away with the list_empty() check because the bare list_for_each_entry_rcu() reduces to that now that we've removed everything else. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212508.378188589@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Optimize some swcounter attr.sample_period==1 pathsPeter Zijlstra
Avoid the rather expensive perf_swevent_set_period() if we know we have to sample every single event anyway. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212508.299508332@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21perf: Allow for custom overflow handlersPeter Zijlstra
in-kernel perf users might wish to have custom actions on the sample interrupt. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <20091120212508.222339539@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-21Merge branch 'tracing/hw-breakpoints' into perf/coreIngo Molnar
Conflicts: arch/x86/kernel/kprobes.c kernel/trace/Makefile Merge reason: hw-breakpoints perf integration is looking good in testing and in reviews, plus conflicts are mounting up - so merge & resolve. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-11-20genirq: Fix spurious irq seqfile conversionThomas Gleixner
single_open data argument must be PDE(inode)->data instead of NULL otherwise seq_file->private is always NULL and we always read the spurious data of irq 0. Reported-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-19SLOW_WORK: Allow a requeueable work item to sleep till the thread is neededDavid Howells
Add a function to allow a requeueable work item to sleep till the thread processing it is needed by the slow-work facility to perform other work. Sometimes a work item can't progress immediately, but must wait for the completion of another work item that's currently being processed by another slow-work thread. In some circumstances, the waiting item could instead - theoretically - put itself back on the queue and yield its thread back to the slow-work facility, thus waiting till it gets processing time again before attempting to progress. This would allow other work items processing time on that thread. However, this only works if there is something on the queue for it to queue behind - otherwise it will just get a thread again immediately, and will end up cycling between the queue and the thread, eating up valuable CPU time. So, slow_work_sleep_till_thread_needed() is provided such that an item can put itself on a wait queue that will wake it up when the event it is actually interested in occurs, then call this function in lieu of calling schedule(). This function will then sleep until either the item's event occurs or another work item appears on the queue. If another work item is queued, but the item's event hasn't occurred, then the work item should requeue itself and yield the thread back to the slow-work facility by returning. This can be used by CacheFiles for an object that is being created on one thread to wait for an object being deleted on another thread where there is nothing on the queue for the creation to go and wait behind. As soon as an item appears on the queue that could be given thread time instead, CacheFiles can stick the creating object back on the queue and return to the slow-work facility - assuming the object deletion didn't also complete. Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19SLOW_WORK: Allow the work items to be viewed through a /proc fileDavid Howells
Allow the executing and queued work items to be viewed through a /proc file for debugging purposes. The contents look something like the following: THR PID ITEM ADDR FL MARK DESC === ===== ================ == ===== ========== 0 3005 ffff880023f52348 a 952ms FSC: OBJ17d3: LOOK 1 3006 ffff880024e33668 2 160ms FSC: OBJ17e5 OP60d3b: Write1/Store fl=2 2 3165 ffff8800296dd180 a 424ms FSC: OBJ17e4: LOOK 3 4089 ffff8800262c8d78 a 212ms FSC: OBJ17ea: CRTN 4 4090 ffff88002792bed8 2 388ms FSC: OBJ17e8 OP60d36: Write1/Store fl=2 5 4092 ffff88002a0ef308 2 388ms FSC: OBJ17e7 OP60d2e: Write1/Store fl=2 6 4094 ffff88002abaf4b8 2 132ms FSC: OBJ17e2 OP60d4e: Write1/Store fl=2 7 4095 ffff88002bb188e0 a 388ms FSC: OBJ17e9: CRTN vsq - ffff880023d99668 1 308ms FSC: OBJ17e0 OP60f91: Write1/EnQ fl=2 vsq - ffff8800295d1740 1 212ms FSC: OBJ16be OP4d4b6: Write1/EnQ fl=2 vsq - ffff880025ba3308 1 160ms FSC: OBJ179a OP58dec: Write1/EnQ fl=2 vsq - ffff880024ec83e0 1 160ms FSC: OBJ17ae OP599f2: Write1/EnQ fl=2 vsq - ffff880026618e00 1 160ms FSC: OBJ17e6 OP60d33: Write1/EnQ fl=2 vsq - ffff880025a2a4b8 1 132ms FSC: OBJ16a2 OP4d583: Write1/EnQ fl=2 vsq - ffff880023cbe6d8 9 212ms FSC: OBJ17eb: LOOK vsq - ffff880024d37590 9 212ms FSC: OBJ17ec: LOOK vsq - ffff880027746cb0 9 212ms FSC: OBJ17ed: LOOK vsq - ffff880024d37ae8 9 212ms FSC: OBJ17ee: LOOK vsq - ffff880024d37cb0 9 212ms FSC: OBJ17ef: LOOK vsq - ffff880025036550 9 212ms FSC: OBJ17f0: LOOK vsq - ffff8800250368e0 9 212ms FSC: OBJ17f1: LOOK vsq - ffff880025036aa8 9 212ms FSC: OBJ17f2: LOOK In the 'THR' column, executing items show the thread they're occupying and queued threads indicate which queue they're on. 'PID' shows the process ID of a slow-work thread that's executing something. 'FL' shows the work item flags. 'MARK' indicates how long since an item was queued or began executing. Lastly, the 'DESC' column permits the owner of an item to give some information. Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19SLOW_WORK: Add delayed_slow_work supportJens Axboe
This adds support for starting slow work with a delay, similar to the functionality we have for workqueues. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19SLOW_WORK: Add support for cancellation of slow workJens Axboe
Add support for cancellation of queued slow work and delayed slow work items. The cancellation functions will wait for items that are pending or undergoing execution to be discarded by the slow work facility. Attempting to enqueue work that is in the process of being cancelled will result in ECANCELED. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19SLOW_WORK: Make slow_work_ops ->get_ref/->put_ref optionalJens Axboe
Make the ability for the slow-work facility to take references on a work item optional as not everyone requires this. Even the internal slow-work stubs them out, so those can be got rid of too. Signed-off-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-19SLOW_WORK: Wait for outstanding work items belonging to a module to clearDavid Howells
Wait for outstanding slow work items belonging to a module to clear when unregistering that module as a user of the facility. This prevents the put_ref code of a work item from being taken away before it returns. Signed-off-by: David Howells <dhowells@redhat.com>
2009-11-18Merge branch 'master' of ↵David S. Miller
master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/sfc/sfe4001.c drivers/net/wireless/libertas/cmd.c drivers/staging/Kconfig drivers/staging/Makefile drivers/staging/rtl8187se/Kconfig drivers/staging/rtl8192e/Kconfig
2009-11-18sysctl: Drop & in front of every proc_handler.Eric W. Biederman
For consistency drop & in front of every proc_handler. Explicity taking the address is unnecessary and it prevents optimizations like stubbing the proc_handlers to NULL. Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Joe Perches <joe@perches.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
2009-11-18itimers: Fix racy writes to cpu_itimer fieldsStanislaw Gruszka
incr_error and error fields of struct cpu_itimer are used when calculating next timer tick in check_cpu_itimers() and should not be modified without tsk->sighand->siglock taken. Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> LKML-Reference: <1253802903-979-1-git-send-email-sgruszka@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-18generic-ipi: Add smp_call_function_any()Rusty Russell
Andrew points out that acpi-cpufreq uses cpumask_any, when it really would prefer to use the same CPU if possible (to avoid an IPI). In general, this seems a good idea to offer. [ tglx: Documented selection preference and Inlined the UP case to avoid the copy of smp_call_function_single() and the extra EXPORT ] Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Len Brown <len.brown@intel.com> Cc: Zhao Yakui <yakui.zhao@intel.com> Cc: Dave Jones <davej@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mike Galbraith <efault@gmx.de> Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-18genirq: switch /proc/irq/*/spurious to seq_fileAlexey Dobriyan
[ tglx: compacted it a bit ] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> LKML-Reference: <20090828181743.GA14050@x200.localdomain> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-18posix-cpu-timers: optimize and document timer_create callbackStanislaw Gruszka
We have already new_timer initialized to all-zeros hence in function initializations are not needed. Document function expectation about new_timer argument as well. Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Cc: johnstul@us.ibm.com Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-18clockevents: Add missing include to pacify sparseH Hartley Sweeten
Include "tick-internal.h" in order to pick up the extern function prototype for clockevents_shutdown(). This quiets the following sparse build noise: warning: symbol 'clockevents_shutdown' was not declared. Should it be static? Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com> LKML-Reference: <BD79186B4FD85F4B8E60E381CAEE190901E24550@mi8nycmail19.Mi8.com> Reviewed-by: Yong Zhang <yong.zhang0@gmail.com> Cc: johnstul@us.ibm.com Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-11-17workqueue: fix race condition in schedule_on_each_cpu()Tejun Heo
Commit 65a64464349883891e21e74af16c05d6e1eeb4e9 ("HWPOISON: Allow schedule_on_each_cpu() from keventd") which allows schedule_on_each_cpu() to be called from keventd added a race condition. schedule_on_each_cpu() may race with cpu hotplug and end up executing the function twice on a cpu. Fix it by moving direct execution into the section protected with get/put_online_cpus(). While at it, update code such that direct execution is done after works have been scheduled for all other cpus and drop unnecessary cpu != orig test from flush loop. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Andi Kleen <ak@linux.intel.com> Acked-by: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-11-17tracing: Prevent build warning: 'ftrace_graph_buf' defined but not usedLai Jiangshan
Prevent build warning when CONFIG_FUNCTION_GRAPH_TRACER is not set. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> LKML-Reference: <4AF24381.5060307@cn.fujitsu.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-11-17tracing: Fix trace_marker outputCarsten Emde
When a string was written to <debugfs>/tracing/trace_marker, some strange characters appeared in the trace output instead of the string, since a vprint function erroneously called a vararg print function with a va_list argument. This patch fixes the problem and simplifies the related code. Signed-off-by: Carsten Emde <C.Emde@osadl.org> LKML-Reference: <4B01AE5D.1010801@osadl.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-11-17ring-buffer: Move access to commit_page up into function usedSteven Rostedt
With the change of the way we process commits. Where a commit only happens at the outer most level, and that we don't need to worry about a commit ending after the rb_start_commit() has been called, the code use to grab the commit page before the tail page to prevent a possible race. But this race no longer exists with the rb_start_commit() rb_end_commit() interface. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-11-17timekeeping: Fix clock_gettime vsyscall time warpLin Ming
Since commit 0a544198 "timekeeping: Move NTP adjusted clock multiplier to struct timekeeper" the clock multiplier of vsyscall is updated with the unmodified clock multiplier of the clock source and not with the NTP adjusted multiplier of the timekeeper. This causes user space observerable time warps: new CLOCK-warp maximum: 120 nsecs, 00000025c337c537 -> 00000025c337c4bf Add a new argument "mult" to update_vsyscall() and hand in the timekeeping internal NTP adjusted multiplier. Signed-off-by: Lin Ming <ming.m.lin@intel.com> Cc: "Zhang Yanmin" <yanmin_zhang@linux.intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Tony Luck <tony.luck@intel.com> LKML-Reference: <1258436990.17765.83.camel@minggr.sh.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-14 23:15:49 +0000