user/sven/linux.git/arch/tile/kernel/smpboot.c, branch v3.18.32

tile: Replace __get_cpu_var uses

2014-08-26T17:45:54Z

__get_cpu_var() is used for multiple purposes in the kernel source. One of them is address calculation via the form &__get_cpu_var(x). This calculates the address for the instance of the percpu variable of the current processor based on an offset. Other use cases are for storing and retrieving data from the current processors percpu area. __get_cpu_var() can be used as an lvalue when writing data or on the right side of an assignment. __get_cpu_var() is defined as : #define __get_cpu_var(var) (*this_cpu_ptr(&(var))) __get_cpu_var() always only does an address determination. However, store and retrieve operations could use a segment prefix (or global register on other platforms) to avoid the address calculation. this_cpu_write() and this_cpu_read() can directly take an offset into a percpu area and use optimized assembly code to read and write per cpu variables. This patch converts __get_cpu_var into either an explicit address calculation using this_cpu_ptr() or into a use of this_cpu operations that use the offset. Thereby address calculations are avoided and less registers are used when code is generated. At the end of the patch set all uses of __get_cpu_var have been removed so the macro is removed too. The patch set includes passes over all arches as well. Once these operations are used throughout then specialized macros can be defined in non -x86 arches as well in order to optimize per cpu access by f.e. using a global register that may be set to the per cpu base. Transformations done to __get_cpu_var() 1. Determine the address of the percpu instance of the current processor. DEFINE_PER_CPU(int, y); int *x = &__get_cpu_var(y); Converts to int *x = this_cpu_ptr(&y); 2. Same as #1 but this time an array structure is involved. DEFINE_PER_CPU(int, y[20]); int *x = __get_cpu_var(y); Converts to int *x = this_cpu_ptr(y); 3. Retrieve the content of the current processors instance of a per cpu variable. DEFINE_PER_CPU(int, y); int x = __get_cpu_var(y) Converts to int x = __this_cpu_read(y); 4. Retrieve the content of a percpu struct DEFINE_PER_CPU(struct mystruct, y); struct mystruct x = __get_cpu_var(y); Converts to memcpy(&x, this_cpu_ptr(&y), sizeof(x)); 5. Assignment to a per cpu variable DEFINE_PER_CPU(int, y) __get_cpu_var(y) = x; Converts to __this_cpu_write(y, x); 6. Increment/Decrement etc of a per cpu variable DEFINE_PER_CPU(int, y); __get_cpu_var(y)++ Converts to __this_cpu_inc(y) Acked-by: Chris Metcalf Signed-off-by: Christoph Lameter Signed-off-by: Tejun Heo

Merge git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile

2013-09-06T18:14:33Z

Pull Tile arch updates from Chris Metcalf: "These changes bring in a bunch of new functionality that has been maintained internally at Tilera over the last year, plus other stray bits of work that I've taken into the tile tree from other folks. The changes include some PCI root complex work, interrupt-driven console support, support for performing fast-path unaligned data fixups by kernel-based JIT code generation, CONFIG_PREEMPT support, vDSO support for gettimeofday(), a serial driver for the tilegx on-chip UART, KGDB support, more optimized string routines, support for ftrace and kprobes, improved ASLR, and many bug fixes. We also remove support for the old TILE64 chip, which is no longer buildable" * git://git.kernel.org/pub/scm/linux/kernel/git/cmetcalf/linux-tile: (85 commits) tile: refresh tile defconfig files tile: rework tile PCI RC: make default consistent DMA mask 32-bit tile: add null check for kzalloc in tile/kernel/setup.c tile: make __write_once a synonym for __read_mostly tile: remove support for TILE64 tile: use asm-generic/bitops/builtin-*.h tile: eliminate no-op "noatomichash" boot argument tile: use standard tile_bundle_bits type in traps.c tile: simplify code referencing hypervisor API addresses tile: change to in comments tile: mark pcibios_init() as __init tile: check for correct compiler earlier in asm-offsets.c tile: use standard 'generic-y' model for tile: use asm-generic version of tile PCI RC: add comment about "PCI hole" problem tile: remove DEBUG_EXTRA_FLAGS kernel config option tile: add virt_to_kpte() API and clean up and document behavior tile: support FRAME_POINTER tile: support reporting Tilera hypervisor statistics ...

tile: support CONFIG_PREEMPT

2013-08-13T20:26:01Z

This change adds support for CONFIG_PREEMPT (full kernel preemption). In addition to the core support, this change includes a number of places where we fix up uses of smp_processor_id() and per-cpu variables. I also eliminate the PAGE_HOME_HERE and PAGE_HOME_UNKNOWN values for page homing, as it turns out they weren't being used. Signed-off-by: Chris Metcalf

tile: delete __cpuinit usage from all tile files

2013-07-14T23:36:54Z

The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. Note that some harmless section mismatch warnings may result, since notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c) are flagged as __cpuinit -- so if we remove the __cpuinit from arch specific callers, we will also get section mismatch warnings. As an intermediate step, we intend to turn the linux/init.h cpuinit content into no-ops as early as possible, since that will get rid of these warnings. In any case, they are temporary and harmless. This removes all the arch/tile uses of the __cpuinit macros from all C files. Currently tile does not have any __CPUINIT used in assembly files. [1] https://lkml.org/lkml/2013/5/20/589 Cc: Chris Metcalf Signed-off-by: Paul Gortmaker

tile: Use generic idle loop

2013-04-08T15:39:28Z

Signed-off-by: Thomas Gleixner Cc: Linus Torvalds Cc: Rusty Russell Cc: Paul McKenney Cc: Peter Zijlstra Reviewed-by: Cc: Srivatsa S. Bhat Cc: Magnus Damm Acked-by: Chris Metcalf Link: http://lkml.kernel.org/r/20130321215235.348460344@linutronix.de Signed-off-by: Thomas Gleixner

tile: Enter idle with preemption disabled

2013-04-08T15:39:28Z

cpu_idle() needs to be called with preemption disabled. Signed-off-by: Thomas Gleixner Cc: Linus Torvalds Cc: Rusty Russell Cc: Paul McKenney Cc: Peter Zijlstra Reviewed-by: Cc: Srivatsa S. Bhat Cc: Magnus Damm Acked-by: Chris Metcalf Link: http://lkml.kernel.org/r/20130321215235.280451779@linutronix.de Signed-off-by: Thomas Gleixner

tile: SMP: Remove call to ipi_call_lock()/ipi_call_unlock()

2012-06-05T15:27:12Z

ipi_call_lock/unlock() lock resp. unlock call_function.lock. This lock protects only the call_function data structure itself, but it's completely unrelated to cpu_online_mask. The mask to which the IPIs are sent is calculated before call_function.lock is taken in smp_call_function_many(), so the locking around set_cpu_online() is pointless and can be removed. [ tglx: Massaged changelog ] Signed-off-by: Yong Zhang Cc: ralf@linux-mips.org Cc: sshtylyov@mvista.com Cc: david.daney@cavium.com Cc: nikunj@linux.vnet.ibm.com Cc: paulmck@linux.vnet.ibm.com Cc: axboe@kernel.dk Cc: peterz@infradead.org Cc: Chris Metcalf Link: http://lkml.kernel.org/r/1338275765-3217-6-git-send-email-yong.zhang0@gmail.com Acked-by: Srivatsa S. Bhat Acked-by: Peter Zijlstra Signed-off-by: Thomas Gleixner

smp: Add task_struct argument to __cpu_up()

2012-04-26T10:06:09Z

Preparatory patch to make the idle thread allocation for secondary cpus generic. Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Rusty Russell Cc: Paul E. McKenney Cc: Srivatsa S. Bhat Cc: Matt Turner Cc: Russell King Cc: Mike Frysinger Cc: Jesper Nilsson Cc: Richard Kuo Cc: Tony Luck Cc: Hirokazu Takata Cc: Ralf Baechle Cc: David Howells Cc: James E.J. Bottomley Cc: Benjamin Herrenschmidt Cc: Martin Schwidefsky Cc: Paul Mundt Cc: David S. Miller Cc: Chris Metcalf Cc: Richard Weinberger Cc: x86@kernel.org Link: http://lkml.kernel.org/r/20120420124556.964170564@linutronix.de

tile/CPU hotplug: Add missing call to notify_cpu_starting()

2012-04-09T18:02:23Z

The scheduler depends on receiving the CPU_STARTING notification, without which we end up into a lot of trouble. So add the missing call to notify_cpu_starting() in the bringup code. Signed-off-by: Srivatsa S. Bhat Signed-off-by: Chris Metcalf

BKL: remove extraneous #include

2010-11-17T16:59:32Z

The big kernel lock has been removed from all these files at some point, leaving only the #include. Remove this too as a cleanup. Signed-off-by: Arnd Bergmann Signed-off-by: Linus Torvalds