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2009-08-23rcu: Merge preemptable-RCU functionality into hierarchical RCUPaul E. McKenney
Create a kernel/rcutree_plugin.h file that contains definitions for preemptable RCU (or, under the #else branch of the #ifdef, empty definitions for the classic non-preemptable semantics). These definitions fit into plugins defined in kernel/rcutree.c for this purpose. This variant of preemptable RCU uses a new algorithm whose read-side expense is roughly that of classic hierarchical RCU under CONFIG_PREEMPT. This new algorithm's update-side expense is similar to that of classic hierarchical RCU, and, in absence of read-side preemption or blocking, is exactly that of classic hierarchical RCU. Perhaps more important, this new algorithm has a much simpler implementation, saving well over 1,000 lines of code compared to mainline's implementation of preemptable RCU, which will hopefully be retired in favor of this new algorithm. The simplifications are obtained by maintaining per-task nesting state for running tasks, and using a simple lock-protected algorithm to handle accounting when tasks block within RCU read-side critical sections, making use of lessons learned while creating numerous user-level RCU implementations over the past 18 months. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <12509746134003-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-23rcu: Simplify rcu_pending()/rcu_check_callbacks() APIPaul E. McKenney
All calls from outside RCU are of the form: if (rcu_pending(cpu)) rcu_check_callbacks(cpu, user); This is silly, instead we put a call to rcu_pending() in rcu_check_callbacks(), and then make the outside calls be to rcu_check_callbacks(). This cuts down on the code a bit and also gives the compiler a better chance of optimizing. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <125097461311-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-23rcu: Use debugfs_remove_recursive() simplify code.Paul E. McKenney
Suggested by Josh Triplett. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> LKML-Reference: <12509746132173-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-23rcu: Merge per-RCU-flavor initialization into pre-existing macroPaul E. McKenney
Rename the RCU_DATA_PTR_INIT() macro to RCU_INIT_FLAVOR() and make it do the rcu_init_one() and rcu_boot_init_percpu_data() calls. Merge the loop that was in the original macro with the loops that were in __rcu_init(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <12509746133916-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-23rcu: Fix online/offline indication for rcudata.csv trace filePaul E. McKenney
The heading said "Online?", but the column had "Y" for offline CPUs and "N" for online CPUs. Swap the "Y" and "N" to match the heading. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <12509746132841-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-23rcu: Consolidate sparse and lockdep declarations in include/linux/rcupdate.hPaul E. McKenney
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <12509746132349-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-23rcu: Renamings to increase RCU clarityPaul E. McKenney
Make RCU-sched, RCU-bh, and RCU-preempt be underlying implementations, with "RCU" defined in terms of one of the three. Update the outdated rcu_qsctr_inc() names, as these functions no longer increment anything. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <12509746132696-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-23rcu: Move private definitions from include/linux/rcutree.h to kernel/rcutree.hPaul E. McKenney
Some information hiding that makes it easier to merge preemptability into rcutree without descending into #include hell. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <1250974613373-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-22rcu: Expunge lingering references to CONFIG_CLASSIC_RCU, optimize on !SMPPaul E. McKenney
A couple of references to CONFIG_CLASSIC_RCU have survived. Although these are harmless, it is past time for them to go. The one in hardirq.h is strictly a readability problem. The two in pagemap.h appear to disable a !SMP performance optimization (which this patch re-enables). This does raise the issue as to whether pagemap.h should really be referring to the CPU implementation. Long term, I intend to make the RCU implementation driven by CONFIG_PREEMPT, at which point these should change from defined(CONFIG_TREE_RCU) to !defined(CONFIG_PREEMPT). In the meantime, is there something else that could be done in pagemap.h? Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <20090822050851.GA8414@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-19rcu: Delay rcu_barrier() wait until beginning of next CPU-hotunplug operation.Paul E. McKenney
Ingo Molnar reported this lockup: [ 200.380003] Hangcheck: hangcheck value past margin! [ 248.192003] INFO: task S99local:2974 blocked for more than 120 seconds. [ 248.194532] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 248.202330] S99local D 0000000c 6256 2974 2687 0x00000000 [ 248.208929] 9c7ebe90 00000086 6b67ef8b 0000000c 9f25a610 81a69869 00000001 820b6990 [ 248.216123] 820b6990 820b6990 9c6e4c20 9c6e4eb4 82c78990 00000000 6b993559 0000000c [ 248.220616] 9c7ebe90 8105f22a 9c6e4eb4 9c6e4c20 00000001 9c7ebe98 9c7ebeb4 81a65cb3 [ 248.229990] Call Trace: [ 248.234049] [<81a69869>] ? _spin_unlock_irqrestore+0x22/0x37 [ 248.239769] [<8105f22a>] ? prepare_to_wait+0x48/0x4e [ 248.244796] [<81a65cb3>] rcu_barrier_cpu_hotplug+0xaa/0xc9 [ 248.250343] [<8105f029>] ? autoremove_wake_function+0x0/0x38 [ 248.256063] [<81062cf2>] notifier_call_chain+0x49/0x71 [ 248.261263] [<81062da0>] raw_notifier_call_chain+0x11/0x13 [ 248.266809] [<81a0b475>] _cpu_down+0x272/0x288 [ 248.271316] [<81a0b4d5>] cpu_down+0x4a/0xa2 [ 248.275563] [<81a0c48a>] store_online+0x2a/0x5e [ 248.280156] [<81a0c460>] ? store_online+0x0/0x5e [ 248.284836] [<814ddc35>] sysdev_store+0x20/0x28 [ 248.289429] [<8112e403>] sysfs_write_file+0xb8/0xe3 [ 248.294369] [<8112e34b>] ? sysfs_write_file+0x0/0xe3 [ 248.299396] [<810e4c8f>] vfs_write+0x91/0x120 [ 248.303817] [<810e4dc1>] sys_write+0x40/0x65 [ 248.308150] [<81002d73>] sysenter_do_call+0x12/0x28 This change moves an RCU grace period delay off of the critical path for CPU-hotunplug operations. Since RCU callback migration is only performed on CPU-hotunplug operations, and since the rcu_barrier() race is provoked only by consecutive CPU-hotunplug operations, it is not necessary to delay the end of a given CPU-hotunplug operation. We can instead choose to delay the beginning of the next CPU-hotunplug operation. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Josh Triplett <josht@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: hugh.dickins@tiscali.co.uk Cc: benh@kernel.crashing.org LKML-Reference: <20090819060614.GA14383@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15rcu: Fix typo in rcu_irq_exit() comment headerJosh Triplett
Signed-off-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: josht@linux.vnet.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: hugh.dickins@tiscali.co.uk Cc: benh@kernel.crashing.org LKML-Reference: <1250355231169-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15rcu: Make rcupreempt_trace.c look at offline CPUsPaul E. McKenney
Given that offline CPUs can now have non-zero counters, we need to dump counters for offline CPUs as well as for online CPUs. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: josht@linux.vnet.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: hugh.dickins@tiscali.co.uk Cc: benh@kernel.crashing.org LKML-Reference: <12503552313921-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15rcu: Make preemptable RCU scan all CPUs when summing RCU countersPaul E. McKenney
This patch eliminates the counter-moving during CPU-offline notifiers, eliminating potential confusion if counters are scanned during counter-movement process. This confusion could result in premature ending of an RCU grace period. For example, if there are two tasks in RCU read-side critical sections (so that the sum of the counters is two), and the counter for the CPU going offline is -2, then moving the count to another CPU can result in the sum momentarily appearing to be zero. Since there are no memory barriers in either case, many more such scenarios are possible. So just don't move the counts!!! Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: josht@linux.vnet.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: hugh.dickins@tiscali.co.uk Cc: benh@kernel.crashing.org LKML-Reference: <12503552312863-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15rcu: Simplify RCU CPU-hotplug notificationPaul E. McKenney
Use the new cpu_notifier() API to simplify RCU's CPU-hotplug notifiers, collapsing down to a single such notifier. This makes it trivial to provide the notifier-ordering guarantee that rcu_barrier() depends on. Also remove redundant open_softirq() calls from Hierarchical RCU notifier. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: josht@linux.vnet.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: hugh.dickins@tiscali.co.uk Cc: benh@kernel.crashing.org LKML-Reference: <12503552312510-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15cpu hotplug: Introduce cpu_notifier() to handle !HOTPLUG_CPU casePaul E. McKenney
This patch introduces a new cpu_notifier() API that is similar to hotcpu_notifier(), but which also notifies of CPUs coming online during boot in the !HOTPLUG_CPU case. Reported-by: Ingo Molnar <mingo@elte.hu> Reported-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Tested-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: josht@linux.vnet.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: benh@kernel.crashing.org LKML-Reference: <12503552312611-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15rcu: Split hierarchical RCU initialization into boot-time and CPU-online piecesPaul E. McKenney
This patch divides the rcutree initialization into boot-time and hotplug-time components, so that the tree data structures are guaranteed to be fully linked at boot time regardless of what might happen in CPU hotplug operations. This makes RCU more resilient against CPU hotplug misbehavior (and vice versa), but more importantly, does a better job of compartmentalizing the code. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: josht@linux.vnet.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: hugh.dickins@tiscali.co.uk Cc: benh@kernel.crashing.org LKML-Reference: <1250355231152-git-send-email-> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-15Merge commit 'v2.6.31-rc6' into core/rcuIngo Molnar
Merge reason: the branch was on pre-rc1 .30, update to latest. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13Linux 2.6.31-rc6v2.6.31-rc6Linus Torvalds
2009-08-13genirq: prevent wakeup of freed irq threadLinus Torvalds
free_irq() can remove an irqaction while the corresponding interrupt is in progress, but free_irq() sets action->thread to NULL unconditionally, which might lead to a NULL pointer dereference in handle_IRQ_event() when the hard interrupt context tries to wake up the handler thread. Prevent this by moving the thread stop after synchronize_irq(). No need to set action->thread to NULL either as action is going to be freed anyway. This fixes a boot crash reported against preempt-rt which uses the mainline irq threads code to implement full irq threading. [ tglx: removed local irqthread variable ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-13Merge branch 'perfcounters-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf_counter: Report the cloning task as parent on perf_counter_fork() perf_counter: Fix an ipi-deadlock perf: Rework/fix the whole read vs group stuff perf_counter: Fix swcounter context invariance perf report: Don't show unresolved DSOs and symbols when -S/-d is used perf tools: Add a general option to enable raw sample records perf tools: Add a per tracepoint counter attribute to get raw sample perf_counter: Provide hw_perf_counter_setup_online() APIs perf list: Fix large list output by using the pager perf_counter, x86: Fix/improve apic fallback perf record: Add missing -C option support for specifying profile cpu perf tools: Fix dso__new handle() to handle deleted DSOs perf tools: Fix fallback to cplus_demangle() when bfd_demangle() is not available perf report: Show the tid too in -D perf record: Fix .tid and .pid fill-in when synthesizing events perf_counter, x86: Fix generic cache events on P6-mobile CPUs perf_counter, x86: Fix lapic printk message
2009-08-13Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: futex: Fix handling of bad requeue syscall pairing futex: Fix compat_futex to be same as futex for REQUEUE_PI locking, sched: Give waitqueue spinlocks their own lockdep classes futex: Update futex_q lock_ptr on requeue proxy lock
2009-08-13Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86: Fix oops in identify_cpu() on CPUs without CPUID x86: Clear incorrectly forced X86_FEATURE_LAHF_LM flag x86, mce: therm_throt - change when we print messages x86: Add reboot quirk for every 5 series MacBook/Pro
2009-08-13Merge branch 'upstream-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2 * 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2: (22 commits) ocfs2: Fix possible deadlock when extending quota file ocfs2: keep index within status_map[] ocfs2: Initialize the cluster we're writing to in a non-sparse extend ocfs2: Remove redundant BUG_ON in __dlm_queue_ast() ocfs2/quota: Release lock for error in ocfs2_quota_write. ocfs2: Define credit counts for quota operations ocfs2: Remove syncjiff field from quota info ocfs2: Fix initialization of blockcheck stats ocfs2: Zero out padding of on disk dquot structure ocfs2: Initialize blocks allocated to local quota file ocfs2: Mark buffer uptodate before calling ocfs2_journal_access_dq() ocfs2: Make global quota files blocksize aligned ocfs2: Use ocfs2_rec_clusters in ocfs2_adjust_adjacent_records. ocfs2: Fix deadlock on umount ocfs2: Add extra credits and access the modified bh in update_edge_lengths. ocfs2: Fail ocfs2_get_block() immediately when a block needs allocation ocfs2: Fix error return in ocfs2_write_cluster() ocfs2: Fix compilation warning for fs/ocfs2/xattr.c ocfs2: Initialize count in aio_write before generic_write_checks ocfs2: log the actual return value of ocfs2_file_aio_write() ...
2009-08-13Merge branch 'for-linus' of git://neil.brown.name/mdLinus Torvalds
* 'for-linus' of git://neil.brown.name/md: md: allow upper limit for resync/reshape to be set when array is read-only md/raid5: Properly remove excess drives after shrinking a raid5/6 md/raid5: make sure a reshape restarts at the correct address. md/raid5: allow new reshape modes to be restarted in the middle. md: never advance 'events' counter by more than 1. Remove deadlock potential in md_open
2009-08-13Merge branch 'sh/for-2.6.31' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6 * 'sh/for-2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6: sh: fix i2c init order on ap325rxa V2 sh: fix i2c init order on Migo-R V2 sh: convert processor device setup functions to arch_initcall()
2009-08-13Make sock_sendpage() use kernel_sendpage()Linus Torvalds
kernel_sendpage() does the proper default case handling for when the socket doesn't have a native sendpage implementation. Now, arguably this might be something that we could instead solve by just specifying that all protocols should do it themselves at the protocol level, but we really only care about the common protocols. Does anybody really care about sendpage on something like Appletalk? Not likely. Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Julien TINNES <julien@cr0.org> Acked-by: Tavis Ormandy <taviso@sdf.lonestar.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-08-13perf_counter: Report the cloning task as parent on perf_counter_fork()Peter Zijlstra
A bug in (9f498cc: perf_counter: Full task tracing) makes profiling multi-threaded apps it go belly up. [ output as: (PID:TID):(PPID:PTID) ] # ./perf report -D | grep FORK 0x4b0 [0x18]: PERF_EVENT_FORK: (3237:3237):(3236:3236) 0xa10 [0x18]: PERF_EVENT_FORK: (3237:3238):(3236:3236) 0xa70 [0x18]: PERF_EVENT_FORK: (3237:3239):(3236:3236) 0xad0 [0x18]: PERF_EVENT_FORK: (3237:3240):(3236:3236) 0xb18 [0x18]: PERF_EVENT_FORK: (3237:3241):(3236:3236) Shows us that the test (27d028d perf report: Update for the new FORK/EXIT events) in builtin-report.c: /* * A thread clone will have the same PID for both * parent and child. */ if (thread == parent) return 0; Will clearly fail. The problem is that perf_counter_fork() reports the actual parent, instead of the cloning thread. Fixing that (with the below patch), yields: # ./perf report -D | grep FORK 0x4c8 [0x18]: PERF_EVENT_FORK: (1590:1590):(1589:1589) 0xbd8 [0x18]: PERF_EVENT_FORK: (1590:1591):(1590:1590) 0xc80 [0x18]: PERF_EVENT_FORK: (1590:1592):(1590:1590) 0x3338 [0x18]: PERF_EVENT_FORK: (1590:1593):(1590:1590) 0x66b0 [0x18]: PERF_EVENT_FORK: (1590:1594):(1590:1590) Which both makes more sense and doesn't confuse perf report anymore. Reported-by: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: paulus@samba.org Cc: Anton Blanchard <anton@samba.org> Cc: Arjan van de Ven <arjan@infradead.org> LKML-Reference: <1250172882.5241.62.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf_counter: Fix an ipi-deadlockPeter Zijlstra
perf_pending_counter() is called from IRQ context and will call perf_counter_disable(), however perf_counter_disable() uses smp_call_function_single() which doesn't fancy being used with IRQs disabled due to IPI deadlocks. Fix this by making it use the local __perf_counter_disable() call and teaching the counter_sched_out() code about pending disables as well. This should cover the case where a counter migrates before the pending queue gets processed. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey J Ashford <cjashfor@us.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: stephane eranian <eranian@googlemail.com> LKML-Reference: <20090813103655.244097721@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf: Rework/fix the whole read vs group stuffPeter Zijlstra
Replace PERF_SAMPLE_GROUP with PERF_SAMPLE_READ and introduce PERF_FORMAT_GROUP to deal with group reads in a more generic way. This allows you to get group reads out of read() as well. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey J Ashford <cjashfor@us.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: stephane eranian <eranian@googlemail.com> LKML-Reference: <20090813103655.117411814@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf_counter: Fix swcounter context invariancePeter Zijlstra
perf_swcounter_is_counting() uses a lock, which means we cannot use swcounters from NMI or when holding that particular lock, this is unintended. The below removes the lock, this opens up race window, but not worse than the swcounters already experience due to RCU traversal of the context in perf_swcounter_ctx_event(). This also fixes the hard lockups while opening a lockdep tracepoint counter. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: stephane eranian <eranian@googlemail.com> Cc: Corey J Ashford <cjashfor@us.ibm.com> LKML-Reference: <1250149915.10001.66.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf report: Don't show unresolved DSOs and symbols when -S/-d is usedArnaldo Carvalho de Melo
We're interested in just those symbols/DSOs, so filter out the unresolved ones. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090812211957.GE3495@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf tools: Add a general option to enable raw sample recordsFrederic Weisbecker
While we can enable the perf sample records per tracepoint counter, we may also want to enable this option for every tracepoint counters to open, so that we don't need to add a :record flag for all of them. Add the -R, --raw-samples options for this purpose. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <1250152039-7284-2-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf tools: Add a per tracepoint counter attribute to get raw sampleFrederic Weisbecker
Add a new flag field while opening a tracepoint perf counter: -e tracepoint_subsystem:tracepoint_name:flags This is intended to be generic although for now it only supports the r[e[c[o[r[d]]]]] flag: ./perf record -e workqueue:workqueue_insertion:record ./perf record -e workqueue:workqueue_insertion:r will have the same effect: enabling the raw samples record for the given tracepoint counter. In the future, we may want to support further flags, separated by commas. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <1250152039-7284-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf_counter: Provide hw_perf_counter_setup_online() APIsIngo Molnar
Provide weak aliases for hw_perf_counter_setup_online(). This is used by the BTS patches (for v2.6.32), but it interacts with fixes so propagate this upstream. (it has no effect as of yet) Also export perf_counter_output() to architecture code. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13perf list: Fix large list output by using the pagerArnaldo Carvalho de Melo
When /sys/kernel/debug is mounted the list can be imense, so use the pager like the other tools. Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090812174459.GB3495@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-13sh: fix i2c init order on ap325rxa V2Magnus Damm
Convert the AP325RXA board code to register devices at arch_initcall() time instead of device_initcall(). This fix unbreaks pcf8563 RTC driver support. Signed-off-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-13sh: fix i2c init order on Migo-R V2Magnus Damm
Convert the Migo-R board code to register devices at arch_initcall() time instead of __initcall(). This fix unbreaks migor_ts touch screen driver support. Signed-off-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-13sh: convert processor device setup functions to arch_initcall()Magnus Damm
Convert the processor platform device setup functions from __initcall() and sometimes device_initcall() to arch_initcall(). This makes sure that the platform devices are registered a bit earlier so the devices are available when drivers register using initcall levels earlier than device_initcall(). A good example is platform devices needed by i2c-sh_mobile.c which registers a bit earlier using subsys_initcall(). Signed-off-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2009-08-13md: allow upper limit for resync/reshape to be set when array is read-onlyNeilBrown
Normally we only allow the upper limit for a reshape to be decreased when the array not performing a sync/recovery/reshape, otherwise there could be races. But if an array is part-way through a reshape when it is assembled the reshape is started immediately leaving no window to set an upper bound. If the array is started read-only, the reshape will be suspended until the array becomes writable, so that provides a window during which it is perfectly safe to reduce the upper limit of a reshape. So: allow the upper limit (sync_max) to be reduced even if the reshape thread is running, as long as the array is still read-only. Signed-off-by: NeilBrown <neilb@suse.de>
2009-08-13md/raid5: Properly remove excess drives after shrinking a raid5/6NeilBrown
We were removing the drives, from the array, but not removing symlinks from /sys/.... and not marking the device as having been removed. Signed-off-by: NeilBrown <neilb@suse.de>
2009-08-13md/raid5: make sure a reshape restarts at the correct address.NeilBrown
This "if" don't allow for the possibility that the number of devices doesn't change, and so sector_nr isn't set correctly in that case. So change '>' to '>='. Signed-off-by: NeilBrown <neilb@suse.de>
2009-08-13md/raid5: allow new reshape modes to be restarted in the middle.NeilBrown
md/raid5 doesn't allow a reshape to restart if it involves writing over the same part of disk that it would be reading from. This happens at the beginning of a reshape that increases the number of devices, at the end of a reshape that decreases the number of devices, and continuously for a reshape that does not change the number of devices. The current code is correct for the "increase number of devices" case as the critical section at the start is handled by userspace performing a backup. It does not work for reducing the number of devices, or the no-change case. For 'reducing', we need to invert the test. For no-change we cannot really be sure things will be safe, so simply require the array to be read-only, which is how the user-space code which carefully starts such arrays works. Signed-off-by: NeilBrown <neilb@suse.de>
2009-08-13md: never advance 'events' counter by more than 1.NeilBrown
When assembling arrays, md allows two devices to have different event counts as long as the difference is only '1'. This is to cope with a system failure between updating the metadata on two difference devices. However there are currently times when we update the event count by 2. This was done to keep the event count even when the array is clean and odd when it is dirty, which allows us to avoid writing common update to spare devices and so allow those spares to go to sleep. This is bad for the above reason. So change it to never increase by two. This means that the alignment between 'odd/even' and 'clean/dirty' might take a little longer to attain, but that is only a small cost. The spares will get a few more updates but that will still be spared (;-) most updates and can still go to sleep. Prior to this patch there was a small chance that after a crash an array would fail to assemble due to the overly large event count mismatch. Signed-off-by: NeilBrown <neilb@suse.de>
2009-08-12Merge branch 'for-linus' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-linus' of git://git.kernel.dk/linux-2.6-block: Remove double removal of blktrace directory
2009-08-12Remove double removal of blktrace directoryAlan D. Brunelle
commit fd51d251e4cdb21f68e9dbc4336514d64a105a79 Author: Stefan Raspl <raspl@linux.vnet.ibm.com> Date: Tue May 19 09:59:08 2009 +0200 blktrace: remove debugfs entries on bad path added in an explicit invocation of debugfs_remove for bt->dir, in blk_remove_buf_file_callback we are also getting the directory removed. On occasion I am seeing memory corruption that I have bisected down to this commit. [The testing involves a (long) series of I/O benchmarks with blktrace invoked around the actual runs.] I believe that this committed patch is correct, but the problem actually lies in the code in blk_remove_buf_file_callback. With this patch I am able to consistently get complete runs whereas previously I could not get a single run to complete. The first part of the patch simply moves the debugfs_remove below the relay_close: the relay_close call will remove files under bt->dir, and so we should not remove the directory until all the files we created have been removed. (Note: This is not sufficient to fix the problem - the file system code has ref counts on the directoy, so our invocation does not cause the directory to actually be removed. Nonetheless, we should not rely upon that feature.) Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-08-12Merge branch 'for-linus' of git://oss.sgi.com/xfs/xfsLinus Torvalds
* 'for-linus' of git://oss.sgi.com/xfs/xfs: xfs: fix spin_is_locked assert on uni-processor builds xfs: check for dinode realtime flag corruption use XFS_CORRUPTION_ERROR in xfs_btree_check_sblock xfs: switch to NOFS allocation under i_lock in xfs_attr_rmtval_get xfs: switch to NOFS allocation under i_lock in xfs_readlink_bmap xfs: switch to NOFS allocation under i_lock in xfs_attr_rmtval_set xfs: switch to NOFS allocation under i_lock in xfs_buf_associate_memory xfs: switch to NOFS allocation under i_lock in xfs_dir_cilookup_result xfs: switch to NOFS allocation under i_lock in xfs_da_buf_make xfs: switch to NOFS allocation under i_lock in xfs_da_state_alloc xfs: switch to NOFS allocation under i_lock in xfs_getbmap xfs: avoid memory allocation under m_peraglock in growfs code
2009-08-12Merge branch 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6: ALSA: hda - Don't override ADC definitions for ALC codecs ALSA: hda - Add missing vmaster initialization for ALC269 ASoC: Add missing DRV_NAME definitions for fsl/* drivers
2009-08-12Merge branch 'zerolen' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/misc-2.6 * 'zerolen' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/misc-2.6: Remove zero-length file drivers/mtd/maps/sbc8240.c
2009-08-12Merge branch 'upstream-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev * 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev: ahci: add workaround for on-board 5723s on some gigabyte boards ahci: Soften up the dmesg on SB600 PMP softreset failure recovery Documentation/kernel-parameters.txt: document libata's ignore_hpa option sata_nv: MSI support, disabled by default libata: OCZ Vertex can't do HPA pata_atiixp: fix second channel support pata_at91: fix resource release
2009-08-12NFS: Fix an O_DIRECT Oops...Trond Myklebust
We can't call nfs_readdata_release()/nfs_writedata_release() without first initialising and referencing args.context. Doing so inside nfs_direct_read_schedule_segment()/nfs_direct_write_schedule_segment() causes an Oops. We should rather be calling nfs_readdata_free()/nfs_writedata_free() in those cases. Looking at the O_DIRECT code, the "struct nfs_direct_req" is already referencing the nfs_open_context for us. Since the readdata and writedata structures carry a reference to that, we can simplify things by getting rid of the extra nfs_open_context references, so that we can replace all instances of nfs_readdata_release()/nfs_writedata_release(). Reported-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Tested-by: Catalin Marinas <catalin.marinas@arm.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>