- 15 Aug, 2009 13 commits
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Martin Schwidefsky authored
update_wall_time calls change_clocksource HZ times per second to check if a new clock source is available. In close to 100% of all calls there is no new clock. Replace the tick based check by an update done with stop_machine. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134810.711836357@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
Add timekeeper_read_clock_ntp and timekeeper_read_clock_raw and use them for getnstimeofday, ktime_get, ktime_get_ts and getrawmonotonic. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134810.435105711@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
The clocksource structure has two multipliers, the unmodified multiplier clock->mult_orig and the NTP corrected multiplier clock->mult. The NTP multiplier is misplaced in the struct clocksource, this is private information of the timekeeping code. Add the mult field to the struct timekeeper to contain the NTP corrected value, keep the unmodifed multiplier in clock->mult and remove clock->mult_orig. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134810.149047645@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
The xtime_nsec value in the timekeeper structure is shifted by a few bits to improve precision. This happens to be the same value as the clock->shift. To improve readability add xtime_shift to the timekeeper and use it instead of the clock->shift. Likewise add ntp_error_shift and replace all (NTP_SCALE_SHIFT - clock->shift) expressions. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.871899606@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
Add struct timekeeper to keep the internal values timekeeping.c needs in regard to the currently selected clock source. This moves the timekeeping intervals, xtime_nsec and the ntp error value from struct clocksource to struct timekeeper. The raw_time is removed from the clocksource as well. It gets treated like xtime as a global variable. Eventually xtime raw_time should be moved to struct timekeeper. [ tglx: minor cleanup ] Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.613209842@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
Move the downgrade of an unstable clocksource from the timer interrupt context into the process context of a work queue thread. This is needed to be able to do the clocksource switch with stop_machine. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.354926067@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
Refactor clocksource watchdog code to make it more readable. Add clocksource_dequeue_watchdog to remove a clocksource from the watchdog list when it is unregistered. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134809.110881699@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
To resume the clocksource watchdog just remove the CLOCK_SOURCE_WATCHDOG bit from the watched clocksource. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134808.880925790@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
The clocksource watchdog marks a clock as highres capable before it checked the deviation from the watchdog clocksource even for a single time. Make sure that the deviation is at least checked once before doing the switch to highres mode. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134808.627795883@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
If a non high-resolution clocksource is first set as override clock and then registered it becomes active even if the system is in one-shot mode. Move the override check from sysfs_override_clocksource to the clocksource selection. That fixes the bug and simplifies the code. The check in clocksource_register for double registration of the same clocksource is removed without replacement. To find the initial clocksource a new weak function in jiffies.c is defined that returns the jiffies clocksource. The architecture code can then override the weak function with a more suitable clocksource, e.g. the TOD clock on s390. [ tglx: Folded in a fix from John Stultz ] Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134808.388024160@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
change_clocksource resets the cycle_last value to zero then sets it to a value read from the clocksource. The reset to zero is required only for the TSC clocksource to make the read_tsc function work after a resume. The reason is that the TSC read function uses cycle_last to detect backwards going TSCs. In the resume case cycle_last contains the TSC value from the last update before the suspend. On resume the TSC starts counting from 0 again and would trip over the cycle_last comparison. This is subtle and surprising. Move the reset to a resume function in the tsc code. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134808.142191175@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Martin Schwidefsky authored
The three inline functions clocksource_read, clocksource_enable and clocksource_disable are simple wrappers of an indirect call plus the copy from and to the mult_orig value. The functions are exclusively used by the timekeeping code which has intimate knowledge of the clocksource anyway. Therefore remove the inline functions. No functional change. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Daniel Walker <dwalker@fifo99.com> LKML-Reference: <20090814134807.903108946@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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John Stultz authored
Move the adjustment of xtime, wall_to_monotonic and the update of the vsyscall variables to the timekeeping code. Signed-off-by: John Stultz <johnstul@us.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> LKML-Reference: <20090814134807.609730216@de.ibm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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- 14 Aug, 2009 1 commit
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Thomas Gleixner authored
Reason: Martin's timekeeping cleanup series depends on both timers/core and mainline changes. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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- 13 Aug, 2009 25 commits
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Linus Torvalds authored
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Linus Torvalds authored
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>
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Linus Torvalds authored
Merge branch 'perfcounters-fixes-for-linus' of 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
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Linus Torvalds authored
Merge branch 'core-fixes-for-linus' of 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
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Linus Torvalds authored
Merge branch 'x86-fixes-for-linus' of 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
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git://git.kernel.org/pub/scm/linux/kernel/git/jlbec/ocfs2Linus Torvalds authored
* '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() ...
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git://neil.brown.name/mdLinus Torvalds authored
* '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
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git://git.kernel.org/pub/scm/linux/kernel/git/lethal/sh-2.6Linus Torvalds authored
* '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()
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Linus Torvalds authored
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>
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Peter Zijlstra authored
A bug in (9f498cc5: 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 (27d028de 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>
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Peter Zijlstra authored
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>
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Peter Zijlstra authored
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>
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Peter Zijlstra authored
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>
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Arnaldo Carvalho de Melo authored
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>
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Frederic Weisbecker authored
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>
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Frederic Weisbecker authored
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>
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Ingo Molnar authored
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>
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Arnaldo Carvalho de Melo authored
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>
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Magnus Damm authored
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>
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Magnus Damm authored
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>
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Magnus Damm authored
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>
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NeilBrown authored
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>
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NeilBrown authored
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>
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NeilBrown authored
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>
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NeilBrown authored
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>
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- 12 Aug, 2009 1 commit
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NeilBrown authored
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>
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