24 Sep, 2009
1 commit
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While it's architecturally clean to have the cgroup debug subsystem be
completely independent of the cgroups framework, it limits its usefulness
for debugging the contents of internal data structures. Move the debug
subsystem code into the scope of all the cgroups data structures to make
more detailed debugging possible.Signed-off-by: Paul Menage
Reviewed-by: Li Zefan
Reviewed-by: KAMEZAWA Hiroyuki
Cc: Balbir Singh
Cc: Dhaval Giani
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
22 Sep, 2009
1 commit
-
…ux/kernel/git/tip/linux-2.6-tip
* 'perfcounters-rename-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf: Tidy up after the big rename
perf: Do the big rename: Performance Counters -> Performance Events
perf_counter: Rename 'event' to event_id/hw_event
perf_counter: Rename list_entry -> group_entry, counter_list -> group_listManually resolved some fairly trivial conflicts with the tracing tree in
include/trace/ftrace.h and kernel/trace/trace_syscalls.c.
21 Sep, 2009
1 commit
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Bye-bye Performance Counters, welcome Performance Events!
In the past few months the perfcounters subsystem has grown out its
initial role of counting hardware events, and has become (and is
becoming) a much broader generic event enumeration, reporting, logging,
monitoring, analysis facility.Naming its core object 'perf_counter' and naming the subsystem
'perfcounters' has become more and more of a misnomer. With pending
code like hw-breakpoints support the 'counter' name is less and
less appropriate.All in one, we've decided to rename the subsystem to 'performance
events' and to propagate this rename through all fields, variables
and API names. (in an ABI compatible fashion)The word 'event' is also a bit shorter than 'counter' - which makes
it slightly more convenient to write/handle as well.Thanks goes to Stephane Eranian who first observed this misnomer and
suggested a rename.User-space tooling and ABI compatibility is not affected - this patch
should be function-invariant. (Also, defconfigs were not touched to
keep the size down.)This patch has been generated via the following script:
FILES=$(find * -type f | grep -vE 'oprofile|[^K]config')
sed -i \
-e 's/PERF_EVENT_/PERF_RECORD_/g' \
-e 's/PERF_COUNTER/PERF_EVENT/g' \
-e 's/perf_counter/perf_event/g' \
-e 's/nb_counters/nb_events/g' \
-e 's/swcounter/swevent/g' \
-e 's/tpcounter_event/tp_event/g' \
$FILESfor N in $(find . -name perf_counter.[ch]); do
M=$(echo $N | sed 's/perf_counter/perf_event/g')
mv $N $M
doneFILES=$(find . -name perf_event.*)
sed -i \
-e 's/COUNTER_MASK/REG_MASK/g' \
-e 's/COUNTER/EVENT/g' \
-e 's/\/event_id/g' \
-e 's/counter/event/g' \
-e 's/Counter/Event/g' \
$FILES... to keep it as correct as possible. This script can also be
used by anyone who has pending perfcounters patches - it converts
a Linux kernel tree over to the new naming. We tried to time this
change to the point in time where the amount of pending patches
is the smallest: the end of the merge window.Namespace clashes were fixed up in a preparatory patch - and some
stylistic fallout will be fixed up in a subsequent patch.( NOTE: 'counters' are still the proper terminology when we deal
with hardware registers - and these sed scripts are a bit
over-eager in renaming them. I've undone some of that, but
in case there's something left where 'counter' would be
better than 'event' we can undo that on an individual basis
instead of touching an otherwise nicely automated patch. )Suggested-by: Stephane Eranian
Acked-by: Peter Zijlstra
Acked-by: Paul Mackerras
Reviewed-by: Arjan van de Ven
Cc: Mike Galbraith
Cc: Arnaldo Carvalho de Melo
Cc: Frederic Weisbecker
Cc: Steven Rostedt
Cc: Benjamin Herrenschmidt
Cc: David Howells
Cc: Kyle McMartin
Cc: Martin Schwidefsky
Cc: "David S. Miller"
Cc: Thomas Gleixner
Cc: "H. Peter Anvin"
Cc:
LKML-Reference:
Signed-off-by: Ingo Molnar
19 Sep, 2009
1 commit
-
Now that the last users of markers have migrated to the event
tracer we can kill off the (now orphan) support code.Signed-off-by: Christoph Hellwig
Acked-by: Mathieu Desnoyers
Cc: Steven Rostedt
Cc: Frederic Weisbecker
LKML-Reference:
Signed-off-by: Ingo Molnar
16 Sep, 2009
1 commit
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Placing dma-coherent.c in driver/base is better than in kernel,
since it contains code to do per-device coherent dma memory
handling.Signed-off-by: Ming Lei
Signed-off-by: Greg Kroah-Hartman
15 Sep, 2009
1 commit
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* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-kconfig:
kconfig: add missing dependency of conf to localyesconfig
kconfig: test if a .config already exists
kconfig: make local .config default for streamline_config
kconfig: test for /boot/config-uname after /proc/config.gz in localconfig
kconfig: unset IKCONFIG_PROC and clean up nesting
kconfig: search for a config to base the local(mod|yes)config on
kconfig: keep config.gz around even if CONFIG_IKCONFIG_PROC is not set
kconfig: have extract-ikconfig read ELF files
kconfig: add check if end exists in extract-ikconfig
kconfig: enable CONFIG_IKCONFIG from streamline_config.pl
kconfig: do not warn about modules built in
kconfig: streamline_config.pl do not stop with no depends
kconfig: add make localyesconfig option
kconfig: make localmodconfig to run streamline_config.pl
kconfig: add streamline_config.pl to scripts
23 Aug, 2009
2 commits
-
Now that CONFIG_TREE_PREEMPT_RCU is in place, there is no
further need for CONFIG_PREEMPT_RCU. Remove it, along with
whatever subtle bugs it may (or may not) contain.Signed-off-by: Paul E. McKenney
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:
Signed-off-by: Ingo Molnar -
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
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:
Signed-off-by: Ingo Molnar
19 Aug, 2009
1 commit
-
If CONFIG_IKCONFIG is set but CONFIG_IKCONFIG_PROC is not, then
gcc will optimize the config.gz out, because nobody uses it.This patch adds "__used" to the config.gz data to keep it around so that
code like extract-ikconfig can still find it.[ Impact: allow extract-ikconfig to find config.gz ]
Signed-off-by: Steven Rostedt
16 Aug, 2009
1 commit
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Merge reason: the branch was on pre-rc1 .30, update to latest.
Signed-off-by: Ingo Molnar
29 Jun, 2009
1 commit
-
…nel/git/tip/linux-2.6-tip
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ftrace: Fix the output of profile
ring-buffer: Make it generally available
ftrace: Remove duplicate newline
tracing: Fix trace_buf_size boot option
ftrace: Fix t_hash_start()
ftrace: Don't manipulate @pos in t_start()
ftrace: Don't increment @pos in g_start()
tracing: Reset iterator in t_start()
trace_stat: Don't increment @pos in seq start()
tracing_bprintk: Don't increment @pos in t_start()
tracing/events: Don't increment @pos in s_start()
25 Jun, 2009
2 commits
-
In hunting down the cause for the hwlat_detector ring buffer spew in
my failed -next builds it became obvious that folks are now treating
ring_buffer as something that is generic independent of tracing and thus,
suitable for public driver consumption.Given that there are only a few minor areas in ring_buffer that have any
reliance on CONFIG_TRACING or CONFIG_FUNCTION_TRACER, provide stubs for
those and make it generally available.Signed-off-by: Paul Mundt
Cc: Jon Masters
Cc: Steven Rostedt
LKML-Reference:
Signed-off-by: Ingo Molnar -
Even though one cannot make use of the audit watch code without
CONFIG_AUDIT_SYSCALL the spaghetti nature of the audit code means that
the audit rule filtering requires that it at least be compiled.Thus build the audit_watch code when we build auditfilter like it was
before cfcad62c74abfef83762dc05a556d21bdf3980a2Clearly this is a point of potential future cleanup..
Reported-by: Frans Pop
Signed-off-by: Eric Paris
Signed-off-by: Al Viro
24 Jun, 2009
2 commits
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Remove Classic RCU, given that the combination of Tree RCU and
the proposed Bloatwatch RCU do everything that Classic RCU can
with fewer bugs.Tree RCU has been default in x86 builds for almost six months,
and seems to be quite reliable, so there does not seem to be
much justification for keeping the Classic RCU code and config
complexity around anymore.Signed-off-by: Paul E. McKenney
Cc: akpm@linux-foundation.org
Cc: niv@us.ibm.com
Cc: dvhltc@us.ibm.com
Cc: dipankar@in.ibm.com
Cc: dhowells@redhat.com
Cc: lethal@linux-sh.org
Cc: kernel@wantstofly.org
Signed-off-by: Ingo Molnar -
In preparation for converting audit to use fsnotify instead of inotify we
seperate the inode watching code into it's own file. This is similar to
how the audit tree watching code is already seperated into audit_tree.cSigned-off-by: Eric Paris
19 Jun, 2009
1 commit
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Enable the use of GCC's coverage testing tool gcov [1] with the Linux
kernel. gcov may be useful for:* debugging (has this code been reached at all?)
* test improvement (how do I change my test to cover these lines?)
* minimizing kernel configurations (do I need this option if the
associated code is never run?)The profiling patch incorporates the following changes:
* change kbuild to include profiling flags
* provide functions needed by profiling code
* present profiling data as files in debugfsNote that on some architectures, enabling gcc's profiling option
"-fprofile-arcs" for the entire kernel may trigger compile/link/
run-time problems, some of which are caused by toolchain bugs and
others which require adjustment of architecture code.For this reason profiling the entire kernel is initially restricted
to those architectures for which it is known to work without changes.
This restriction can be lifted once an architecture has been tested
and found compatible with gcc's profiling. Profiling of single files
or directories is still available on all platforms (see config help
text).[1] http://gcc.gnu.org/onlinedocs/gcc/Gcov.html
Signed-off-by: Peter Oberparleiter
Cc: Andi Kleen
Cc: Huang Ying
Cc: Li Wei
Cc: Michael Ellerman
Cc: Ingo Molnar
Cc: Heiko Carstens
Cc: Martin Schwidefsky
Cc: Rusty Russell
Cc: WANG Cong
Cc: Sam Ravnborg
Cc: Jeff Dike
Cc: Al Viro
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
17 Jun, 2009
1 commit
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Move supplementary groups implementation to kernel/groups.c .
kernel/sys.c already accumulated quite a few random stuff.Do strictly copy/paste + add required headers to compile. Compile-tested
on many configs and archs.Signed-off-by: Alexey Dobriyan
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Jun, 2009
1 commit
-
Conflicts:
arch/x86/kernel/irqinit.c
arch/x86/kernel/irqinit_64.c
arch/x86/kernel/traps.c
arch/x86/mm/fault.c
include/linux/sched.h
kernel/exit.c
24 Apr, 2009
1 commit
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Conflicts:
arch/x86/kernel/ptrace.cMerge reason: fix the conflict above, and also pick up the CONFIG_BROKEN
dependency change from upstream so that we can remove it
here.Signed-off-by: Ingo Molnar
15 Apr, 2009
1 commit
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Jeremy Fitzhardinge reported this build failure:
LD .tmp_vmlinux1
arch/x86/kernel/built-in.o: In function `ds_take_timestamp':
git/linux/arch/x86/kernel/ds.c:1380: undefined reference to `trace_clock_global'
git/linux/arch/x86/kernel/ds.c:1380: undefined reference to `trace_clock_global'Which is due to !CONFIG_TRACING && CONFIG_X86_DS=y.
Expose the trace clock code to CONFIG_X86_DS as well.
[ Unfortunately librarizing doesnt work well - ancient architectures
with no raw_local_irq_save() primitive break the build. ]Reported-by: Jeremy Fitzhardinge
LKML-Reference:
Signed-off-by: Ingo Molnar
08 Apr, 2009
1 commit
-
Conflicts:
arch/powerpc/include/asm/systbl.h
arch/powerpc/include/asm/unistd.h
include/linux/init_task.hMerge reason: the conflicts are non-trivial: PowerPC placement
of sys_perf_counter_open has to be mixed with the
new preadv/pwrite syscalls.Signed-off-by: Ingo Molnar
07 Apr, 2009
1 commit
-
Conflicts:
kernel/sysctl.c
06 Apr, 2009
1 commit
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Merge reason: we have gathered quite a few conflicts, need to merge upstream
Conflicts:
arch/powerpc/kernel/Makefile
arch/x86/ia32/ia32entry.S
arch/x86/include/asm/hardirq.h
arch/x86/include/asm/unistd_32.h
arch/x86/include/asm/unistd_64.h
arch/x86/kernel/cpu/common.c
arch/x86/kernel/irq.c
arch/x86/kernel/syscall_table_32.S
arch/x86/mm/iomap_32.c
include/linux/sched.h
kernel/MakefileSigned-off-by: Ingo Molnar
03 Apr, 2009
1 commit
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Create a dynamically sized pool of threads for doing very slow work items, such
as invoking mkdir() or rmdir() - things that may take a long time and may
sleep, holding mutexes/semaphores and hogging a thread, and are thus unsuitable
for workqueues.The number of threads is always at least a settable minimum, but more are
started when there's more work to do, up to a limit. Because of the nature of
the load, it's not suitable for a 1-thread-per-CPU type pool. A system with
one CPU may well want several threads.This is used by FS-Cache to do slow caching operations in the background, such
as looking up, creating or deleting cache objects.Signed-off-by: David Howells
Acked-by: Serge Hallyn
Acked-by: Steve Dickson
Acked-by: Trond Myklebust
Acked-by: Al Viro
Tested-by: Daire Byrne
26 Feb, 2009
1 commit
-
Conflicts:
arch/x86/kernel/apic/apic.c
arch/x86/kernel/irqinit_32.cSigned-off-by: Ingo Molnar
19 Feb, 2009
1 commit
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Compilation of kprobes.c with CONFIG_PM unset is broken due to some broken
config dependncies. Fix that.Signed-off-by: Rafael J. Wysocki
Reported-by: Ingo Molnar
Tested-by: Masami Hiramatsu
Cc: Len Brown
Acked-by: Pavel Machek
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
12 Feb, 2009
1 commit
21 Jan, 2009
1 commit
-
Conflicts:
include/linux/syscalls.h
19 Jan, 2009
1 commit
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Conflicts:
arch/x86/include/asm/pda.hWe merge tip/core/percpu into tip/perfcounters/core because of a
semantic and contextual conflict: the former eliminates the PDA,
while the latter extends it with apic_perf_irqs field.Resolve the conflict by moving the new field to the irq_cpustat
structure on 64-bit too.Signed-off-by: Ingo Molnar
16 Jan, 2009
1 commit
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Decoupling allows:
* hung tasks check to happen at very low priority
* hung tasks check and softlockup to be enabled/disabled independently
at compile and/or run-time* individual panic settings to be enabled disabled independently
at compile and/or run-time* softlockup threshold to be reduced without increasing hung tasks
poll frequency (hung task check is expensive relative to softlock watchdog)* hung task check to be zero over-head when disabled at run-time
Signed-off-by: Mandeep Singh Baines
Signed-off-by: Ingo Molnar
15 Jan, 2009
1 commit
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Fix the sparc build - we were including `up.o' on SMP builds, when
CONFIG_USE_GENERIC_SMP_HELPERS=n.Tested-by: Robert Reif
Fixed-by: Robert Reif
Cc: David Miller
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
11 Jan, 2009
2 commits
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If you do
smp_call_function_single(expression-with-side-effects, ...)
then expression-with-side-effects never gets evaluated on UP builds.
As always, implementing it in C is the correct thing to do.
While we're there, uninline it for size and possible header dependency
reasons.And create a new kernel/up.c, as a place in which to put
uniprocessor-specific code and storage. It should mirror kernel/smp.c.Signed-off-by: Andrew Morton
Signed-off-by: Ingo Molnar -
Conflicts:
include/linux/kernel_stat.h
08 Jan, 2009
1 commit
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Right now, most of the kernel boot is strictly synchronous, such that
various hardware delays are done sequentially.In order to make the kernel boot faster, this patch introduces
infrastructure to allow doing some of the initialization steps
asynchronously, which will hide significant portions of the hardware delays
in practice.In order to not change device order and other similar observables, this
patch does NOT do full parallel initialization.Rather, it operates more in the way an out of order CPU does; the work may
be done out of order and asynchronous, but the observable effects
(instruction retiring for the CPU) are still done in the original sequence.Signed-off-by: Arjan van de Ven
31 Dec, 2008
1 commit
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* 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (63 commits)
stacktrace: provide save_stack_trace_tsk() weak alias
rcu: provide RCU options on non-preempt architectures too
printk: fix discarding message when recursion_bug
futex: clean up futex_(un)lock_pi fault handling
"Tree RCU": scalable classic RCU implementation
futex: rename field in futex_q to clarify single waiter semantics
x86/swiotlb: add default swiotlb_arch_range_needs_mapping
x86/swiotlb: add default physbus conversion
x86: unify pci iommu setup and allow swiotlb to compile for 32 bit
x86: add swiotlb allocation functions
swiotlb: consolidate swiotlb info message printing
swiotlb: support bouncing of HighMem pages
swiotlb: factor out copy to/from device
swiotlb: add arch hook to force mapping
swiotlb: allow architectures to override physbusphys conversions
swiotlb: add comment where we handle the overflow of a dma mask on 32 bit
rcu: fix rcutorture behavior during reboot
resources: skip sanity check of busy resources
swiotlb: move some definitions to header
swiotlb: allow architectures to override swiotlb pool allocation
...Fix up trivial conflicts in
arch/x86/kernel/Makefile
arch/x86/mm/init_32.c
include/linux/hardirq.h
as per Ingo's suggestions.
29 Dec, 2008
2 commits
-
Conflicts:
fs/exec.c
include/linux/init_task.hSimple context conflicts.
-
…/git/tip/linux-2.6-tip
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (31 commits)
sched: fix warning in fs/proc/base.c
schedstat: consolidate per-task cpu runtime stats
sched: use RCU variant of list traversal in for_each_leaf_rt_rq()
sched, cpuacct: export percpu cpuacct cgroup stats
sched, cpuacct: refactoring cpuusage_read / cpuusage_write
sched: optimize update_curr()
sched: fix wakeup preemption clock
sched: add missing arch_update_cpu_topology() call
sched: let arch_update_cpu_topology indicate if topology changed
sched: idle_balance() does not call load_balance_newidle()
sched: fix sd_parent_degenerate on non-numa smp machine
sched: add uid information to sched_debug for CONFIG_USER_SCHED
sched: move double_unlock_balance() higher
sched: update comment for move_task_off_dead_cpu
sched: fix inconsistency when redistribute per-cpu tg->cfs_rq shares
sched/rt: removed unneeded defintion
sched: add hierarchical accounting to cpu accounting controller
sched: include group statistics in /proc/sched_debug
sched: rename SCHED_NO_NO_OMIT_FRAME_POINTER => SCHED_OMIT_FRAME_POINTER
sched: clean up SCHED_CPUMASK_ALLOC
...
19 Dec, 2008
1 commit
-
This patch fixes a long-standing performance bug in classic RCU that
results in massive internal-to-RCU lock contention on systems with
more than a few hundred CPUs. Although this patch creates a separate
flavor of RCU for ease of review and patch maintenance, it is intended
to replace classic RCU.This patch still handles stress better than does mainline, so I am still
calling it ready for inclusion. This patch is against the -tip tree.
Nevertheless, experience on an actual 1000+ CPU machine would still be
most welcome.Most of the changes noted below were found while creating an rcutiny
(which should permit ejecting the current rcuclassic) and while doing
detailed line-by-line documentation.Updates from v9 (http://lkml.org/lkml/2008/12/2/334):
o Fixes from remainder of line-by-line code walkthrough,
including comment spelling, initialization, undesirable
narrowing due to type conversion, removing redundant memory
barriers, removing redundant local-variable initialization,
and removing redundant local variables.I do not believe that any of these fixes address the CPU-hotplug
issues that Andi Kleen was seeing, but please do give it a whirl
in case the machine is smarter than I am.A writeup from the walkthrough may be found at the following
URL, in case you are suffering from terminal insomnia or
masochism:http://www.kernel.org/pub/linux/kernel/people/paulmck/tmp/rcutree-walkthrough.2008.12.16a.pdf
o Made rcutree tracing use seq_file, as suggested some time
ago by Lai Jiangshan.o Added a .csv variant of the rcudata debugfs trace file, to allow
people having thousands of CPUs to drop the data into
a spreadsheet. Tested with oocalc and gnumeric. Updated
documentation to suit.Updates from v8 (http://lkml.org/lkml/2008/11/15/139):
o Fix a theoretical race between grace-period initialization and
force_quiescent_state() that could occur if more than three
jiffies were required to carry out the grace-period
initialization. Which it might, if you had enough CPUs.o Apply Ingo's printk-standardization patch.
o Substitute local variables for repeated accesses to global
variables.o Fix comment misspellings and redundant (but harmless) increments
of ->n_rcu_pending (this latter after having explicitly added it).o Apply checkpatch fixes.
Updates from v7 (http://lkml.org/lkml/2008/10/10/291):
o Fixed a number of problems noted by Gautham Shenoy, including
the cpu-stall-detection bug that he was having difficulty
convincing me was real. ;-)o Changed cpu-stall detection to wait for ten seconds rather than
three in order to reduce false positive, as suggested by Ingo
Molnar.o Produced a design document (http://lwn.net/Articles/305782/).
The act of writing this document uncovered a number of both
theoretical and "here and now" bugs as noted below.o Fix dynticks_nesting accounting confusion, simplify WARN_ON()
condition, fix kerneldoc comments, and add memory barriers
in dynticks interface functions.o Add more data to tracing.
o Remove unused "rcu_barrier" field from rcu_data structure.
o Count calls to rcu_pending() from scheduling-clock interrupt
to use as a surrogate timebase should jiffies stop counting.o Fix a theoretical race between force_quiescent_state() and
grace-period initialization. Yes, initialization does have to
go on for some jiffies for this race to occur, but given enough
CPUs...Updates from v6 (http://lkml.org/lkml/2008/9/23/448):
o Fix a number of checkpatch.pl complaints.
o Apply review comments from Ingo Molnar and Lai Jiangshan
on the stall-detection code.o Fix several bugs in !CONFIG_SMP builds.
o Fix a misspelled config-parameter name so that RCU now announces
at boot time if stall detection is configured.o Run tests on numerous combinations of configurations parameters,
which after the fixes above, now build and run correctly.Updates from v5 (http://lkml.org/lkml/2008/9/15/92, bad subject line):
o Fix a compiler error in the !CONFIG_FANOUT_EXACT case (blew a
changeset some time ago, and finally got around to retesting
this option).o Fix some tracing bugs in rcupreempt that caused incorrect
totals to be printed.o I now test with a more brutal random-selection online/offline
script (attached). Probably more brutal than it needs to be
on the people reading it as well, but so it goes.o A number of optimizations and usability improvements:
o Make rcu_pending() ignore the grace-period timeout when
there is no grace period in progress.o Make force_quiescent_state() avoid going for a global
lock in the case where there is no grace period in
progress.o Rearrange struct fields to improve struct layout.
o Make call_rcu() initiate a grace period if RCU was
idle, rather than waiting for the next scheduling
clock interrupt.o Invoke rcu_irq_enter() and rcu_irq_exit() only when
idle, as suggested by Andi Kleen. I still don't
completely trust this change, and might back it out.o Make CONFIG_RCU_TRACE be the single config variable
manipulated for all forms of RCU, instead of the prior
confusion.o Document tracing files and formats for both rcupreempt
and rcutree.Updates from v4 for those missing v5 given its bad subject line:
o Separated dynticks interface so that NMIs and irqs call separate
functions, greatly simplifying it. In particular, this code
no longer requires a proof of correctness. ;-)o Separated dynticks state out into its own per-CPU structure,
avoiding the duplicated accounting.o The case where a dynticks-idle CPU runs an irq handler that
invokes call_rcu() is now correctly handled, forcing that CPU
out of dynticks-idle mode.o Review comments have been applied (thank you all!!!).
For but one example, fixed the dynticks-ordering issue that
Manfred pointed out, saving me much debugging. ;-)o Adjusted rcuclassic and rcupreempt to handle dynticks changes.
Attached is an updated patch to Classic RCU that applies a hierarchy,
greatly reducing the contention on the top-level lock for large machines.
This passes 10-hour concurrent rcutorture and online-offline testing on
128-CPU ppc64 without dynticks enabled, and exposes some timekeeping
bugs in presence of dynticks (exciting working on a system where
"sleep 1" hangs until interrupted...), which were fixed in the
2.6.27 kernel. It is getting more reliable than mainline by some
measures, so the next version will be against -tip for inclusion.
See also Manfred Spraul's recent patches (or his earlier work from
2004 at http://marc.info/?l=linux-kernel&m=108546384711797&w=2).
We will converge onto a common patch in the fullness of time, but are
currently exploring different regions of the design space. That said,
I have already gratefully stolen quite a few of Manfred's ideas.This patch provides CONFIG_RCU_FANOUT, which controls the bushiness
of the RCU hierarchy. Defaults to 32 on 32-bit machines and 64 on
64-bit machines. If CONFIG_NR_CPUS is less than CONFIG_RCU_FANOUT,
there is no hierarchy. By default, the RCU initialization code will
adjust CONFIG_RCU_FANOUT to balance the hierarchy, so strongly NUMA
architectures may choose to set CONFIG_RCU_FANOUT_EXACT to disable
this balancing, allowing the hierarchy to be exactly aligned to the
underlying hardware. Up to two levels of hierarchy are permitted
(in addition to the root node), allowing up to 16,384 CPUs on 32-bit
systems and up to 262,144 CPUs on 64-bit systems. I just know that I
am going to regret saying this, but this seems more than sufficient
for the foreseeable future. (Some architectures might wish to set
CONFIG_RCU_FANOUT=4, which would limit such architectures to 64 CPUs.
If this becomes a real problem, additional levels can be added, but I
doubt that it will make a significant difference on real hardware.)In the common case, a given CPU will manipulate its private rcu_data
structure and the rcu_node structure that it shares with its immediate
neighbors. This can reduce both lock and memory contention by multiple
orders of magnitude, which should eliminate the need for the strange
manipulations that are reported to be required when running Linux on
very large systems.Some shortcomings:
o More bugs will probably surface as a result of an ongoing
line-by-line code inspection.Patches will be provided as required.
o There are probably hangs, rcutorture failures, &c. Seems
quite stable on a 128-CPU machine, but that is kind of small
compared to 4096 CPUs. However, seems to do better than
mainline.Patches will be provided as required.
o The memory footprint of this version is several KB larger
than rcuclassic.A separate UP-only rcutiny patch will be provided, which will
reduce the memory footprint significantly, even compared
to the old rcuclassic. One such patch passes light testing,
and has a memory footprint smaller even than rcuclassic.
Initial reaction from various embedded guys was "it is not
worth it", so am putting it aside.Credits:
o Manfred Spraul for ideas, review comments, and bugs spotted,
as well as some good friendly competition. ;-)o Josh Triplett, Ingo Molnar, Peter Zijlstra, Mathieu Desnoyers,
Lai Jiangshan, Andi Kleen, Andy Whitcroft, and Andrew Morton
for reviews and comments.o Thomas Gleixner for much-needed help with some timer issues
(see patches below).o Jon M. Tollefson, Tim Pepper, Andrew Theurer, Jose R. Santos,
Andy Whitcroft, Darrick Wong, Nishanth Aravamudan, Anton
Blanchard, Dave Kleikamp, and Nathan Lynch for keeping machines
alive despite my heavy abuse^Wtesting.Signed-off-by: Paul E. McKenney
Signed-off-by: Ingo Molnar
08 Dec, 2008
1 commit
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Implement the core kernel bits of Performance Counters subsystem.
The Linux Performance Counter subsystem provides an abstraction of
performance counter hardware capabilities. It provides per task and per
CPU counters, and it provides event capabilities on top of those.Performance counters are accessed via special file descriptors.
There's one file descriptor per virtual counter used.The special file descriptor is opened via the perf_counter_open()
system call:int
perf_counter_open(u32 hw_event_type,
u32 hw_event_period,
u32 record_type,
pid_t pid,
int cpu);The syscall returns the new fd. The fd can be used via the normal
VFS system calls: read() can be used to read the counter, fcntl()
can be used to set the blocking mode, etc.Multiple counters can be kept open at a time, and the counters
can be poll()ed.See more details in Documentation/perf-counters.txt.
Signed-off-by: Thomas Gleixner
Signed-off-by: Ingo Molnar
19 Nov, 2008
1 commit
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Conflicts:
kernel/Makefile