user/sven/linux.git/include/linux/stop_machine.h, branch v4.1.15

stop_machine: Introduce stop_two_cpus()

2013-10-09T10:40:45Z

Introduce stop_two_cpus() in order to allow controlled swapping of two tasks. It repurposes the stop_machine() state machine but only stops the two cpus which we can do with on-stack structures and avoid machine wide synchronization issues. The ordering of CPUs is important to avoid deadlocks. If unordered then two cpus calling stop_two_cpus on each other simultaneously would attempt to queue in the opposite order on each CPU causing an AB-BA style deadlock. By always having the lowest number CPU doing the queueing of works, we can guarantee that works are always queued in the same order, and deadlocks are avoided. Signed-off-by: Peter Zijlstra [ Implemented deadlock avoidance. ] Signed-off-by: Rik van Riel Cc: Andrea Arcangeli Cc: Johannes Weiner Cc: Srikar Dronamraju Signed-off-by: Mel Gorman Link: http://lkml.kernel.org/r/1381141781-10992-38-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar

Remove all #inclusions of asm/system.h

2012-03-28T17:30:03Z

Remove all #inclusions of asm/system.h preparatory to splitting and killing it. Performed with the following command: perl -p -i -e 's!^#\s*include\s*.*\n!!' `grep -Irl '^#\s*include\s*' *` Signed-off-by: David Howells

stop_machine.h: fix implicit use of smp.h for smp_processor_id

2011-10-31T23:32:28Z

This will show up on MIPS when we fix all the implicit header presences that are because of module.h being everywhere. In file included from kernel/trace/ftrace.c:16: include/linux/stop_machine.h: In function 'stop_one_cpu': include/linux/stop_machine.h:50: error: implicit declaration of function 'smp_processor_id' include/linux/stop_machine.h: In function 'stop_cpus': include/linux/stop_machine.h:80: error: implicit declaration of function 'raw_smp_processor_id' Signed-off-by: Paul Gortmaker

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial

2011-07-25T20:56:39Z

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits) fs: Merge split strings treewide: fix potentially dangerous trailing ';' in #defined values/expressions uwb: Fix misspelling of neighbourhood in comment net, netfilter: Remove redundant goto in ebt_ulog_packet trivial: don't touch files that are removed in the staging tree lib/vsprintf: replace link to Draft by final RFC number doc: Kconfig: `to be' -> `be' doc: Kconfig: Typo: square -> squared doc: Konfig: Documentation/power/{pm => apm-acpi}.txt drivers/net: static should be at beginning of declaration drivers/media: static should be at beginning of declaration drivers/i2c: static should be at beginning of declaration XTENSA: static should be at beginning of declaration SH: static should be at beginning of declaration MIPS: static should be at beginning of declaration ARM: static should be at beginning of declaration rcu: treewide: Do not use rcu_read_lock_held when calling rcu_dereference_check Update my e-mail address PCIe ASPM: forcedly -> forcibly gma500: push through device driver tree ... Fix up trivial conflicts: - arch/arm/mach-ep93xx/dma-m2p.c (deleted) - drivers/gpio/gpio-ep93xx.c (renamed and context nearby) - drivers/net/r8169.c (just context changes)

x86, mtrr: use stop_machine APIs for doing MTRR rendezvous

2011-06-27T22:17:13Z

MTRR rendezvous sequence is not implemened using stop_machine() before, as this gets called both from the process context aswell as the cpu online paths (where the cpu has not come online and the interrupts are disabled etc). Now that we have a new stop_machine_from_inactive_cpu() API, use it for rendezvous during mtrr init of a logical processor that is coming online. For the rest (runtime MTRR modification, system boot, resume paths), use stop_machine() to implement the rendezvous sequence. This will consolidate and cleanup the code. Signed-off-by: Suresh Siddha Link: http://lkml.kernel.org/r/20110623182057.076997177@sbsiddha-MOBL3.sc.intel.com Signed-off-by: H. Peter Anvin

stop_machine: implement stop_machine_from_inactive_cpu()

2011-06-27T22:17:08Z

Currently, mtrr wants stop_machine functionality while a CPU is being brought up. As stop_machine() requires the calling CPU to be active, mtrr implements its own stop_machine using stop_one_cpu() on each online CPU. This doesn't only unnecessarily duplicate complex logic but also introduces a possibility of deadlock when it races against the generic stop_machine(). This patch implements stop_machine_from_inactive_cpu() to serve such use cases. Its functionality is basically the same as stop_machine(); however, it should be called from a CPU which isn't active and doesn't depend on working scheduling on the calling CPU. This is achieved by using busy loops for synchronization and open-coding stop_cpus queuing and waiting with direct invocation of fn() for local CPU inbetween. Signed-off-by: Tejun Heo Link: http://lkml.kernel.org/r/20110623182056.982526827@sbsiddha-MOBL3.sc.intel.com Signed-off-by: Suresh Siddha Cc: Ingo Molnar Cc: Andrew Morton Cc: Linus Torvalds Cc: Peter Zijlstra Signed-off-by: H. Peter Anvin

x86, mtrr: lock stop machine during MTRR rendezvous sequence

2011-06-27T21:00:46Z

MTRR rendezvous sequence using stop_one_cpu_nowait() can potentially happen in parallel with another system wide rendezvous using stop_machine(). This can lead to deadlock (The order in which works are queued can be different on different cpu's. Some cpu's will be running the first rendezvous handler and others will be running the second rendezvous handler. Each set waiting for the other set to join for the system wide rendezvous, leading to a deadlock). MTRR rendezvous sequence is not implemented using stop_machine() as this gets called both from the process context aswell as the cpu online paths (where the cpu has not come online and the interrupts are disabled etc). stop_machine() works with only online cpus. For now, take the stop_machine mutex in the MTRR rendezvous sequence that gets called from an online cpu (here we are in the process context and can potentially sleep while taking the mutex). And the MTRR rendezvous that gets triggered during cpu online doesn't need to take this stop_machine lock (as the stop_machine() already ensures that there is no cpu hotplug going on in parallel by doing get_online_cpus()) TBD: Pursue a cleaner solution of extending the stop_machine() infrastructure to handle the case where the calling cpu is still not online and use this for MTRR rendezvous sequence. fixes: https://bugzilla.novell.com/show_bug.cgi?id=672008 Reported-by: Vadim Kotelnikov Signed-off-by: Suresh Siddha Link: http://lkml.kernel.org/r/20110623182056.807230326@sbsiddha-MOBL3.sc.intel.com Cc: stable@kernel.org # 2.6.35+, backport a week or two after this gets more testing in mainline Signed-off-by: H. Peter Anvin

stop_machine.h: "disables preeempt" -> "disables preemption"

2011-06-20T13:52:33Z

Use the noun instead of a misspelled verb. Signed-off-by: Jonathan Neuschäfer Signed-off-by: Jiri Kosina

Fix common misspellings

2011-03-31T14:26:23Z

Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi

stopmachine: Define __stop_machine when CONFIG_STOP_MACHINE=n

2010-10-14T06:55:28Z

Define dummy __stop_machine() function even when CONFIG_STOP_MACHINE=n. This getcpu-required version of stop_machine() will be used from poke_text_smp(). Signed-off-by: Masami Hiramatsu Acked-by: Tejun Heo Cc: Rusty Russell Cc: Ananth N Mavinakayanahalli Cc: 2nddept-manager@sdl.hitachi.co.jp Cc: Peter Zijlstra LKML-Reference: <20101014031030.4100.34156.stgit@ltc236.sdl.hitachi.co.jp> Signed-off-by: Ingo Molnar