21 Nov, 2011
1 commit
-
cppcheck reported:
[lib/dma-debug.c:248] -> [lib/dma-debug.c:248]: (style) Same expression on both sides of '=='.Signed-off-by: Thomas Jarosch
Signed-off-by: Joerg Roedel
08 Nov, 2011
1 commit
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* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (47 commits)
forcedeth: fix a few sparse warnings (variable shadowing)
forcedeth: Improve stats counters
forcedeth: remove unneeded stats updates
forcedeth: Acknowledge only interrupts that are being processed
forcedeth: fix race when unloading module
MAINTAINERS/rds: update maintainer
wanrouter: Remove kernel_lock annotations
usbnet: fix oops in usbnet_start_xmit
ixgbe: Fix compile for kernel without CONFIG_PCI_IOV defined
etherh: Add MAINTAINERS entry for etherh
bonding: comparing a u8 with -1 is always false
sky2: fix regression on Yukon Optima
netlink: clarify attribute length check documentation
netlink: validate NLA_MSECS length
i825xx:xscale:8390:freescale: Fix Kconfig dependancies
macvlan: receive multicast with local address
tg3: Update version to 3.121
tg3: Eliminate timer race with reset_task
tg3: Schedule at most one tg3_reset_task run
tg3: Obtain PCI function number from device
...
07 Nov, 2011
1 commit
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* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
Revert "tracing: Include module.h in define_trace.h"
irq: don't put module.h into irq.h for tracking irqgen modules.
bluetooth: macroize two small inlines to avoid module.h
ip_vs.h: fix implicit use of module_get/module_put from module.h
nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
include: replace linux/module.h with "struct module" wherever possible
include: convert various register fcns to macros to avoid include chaining
crypto.h: remove unused crypto_tfm_alg_modname() inline
uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
pm_runtime.h: explicitly requires notifier.h
linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
miscdevice.h: fix up implicit use of lists and types
stop_machine.h: fix implicit use of smp.h for smp_processor_id
of: fix implicit use of errno.h in include/linux/of.h
of_platform.h: delete needless include
acpi: remove module.h include from platform/aclinux.h
miscdevice.h: delete unnecessary inclusion of module.h
device_cgroup.h: delete needless include
net: sch_generic remove redundant use of
net: inet_timewait_sock doesnt need
...Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in
- drivers/media/dvb/frontends/dibx000_common.c
- drivers/media/video/{mt9m111.c,ov6650.c}
- drivers/mfd/ab3550-core.c
- include/linux/dmaengine.h
05 Nov, 2011
1 commit
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L2TP for example uses NLA_MSECS like this:
policy:
[L2TP_ATTR_RECV_TIMEOUT] = { .type = NLA_MSECS, },
code:
if (info->attrs[L2TP_ATTR_RECV_TIMEOUT])
cfg.reorder_timeout = nla_get_msecs(info->attrs[L2TP_ATTR_RECV_TIMEOUT]);As nla_get_msecs() is essentially nla_get_u64() plus the
conversion to a HZ-based value, this will not properly
reject attributes from userspace that aren't long enough
and might overrun the message.Add NLA_MSECS to the attribute minlen array to check the
size properly.Cc: Thomas Graf
Cc: stable@vger.kernel.org
Signed-off-by: Johannes Berg
Signed-off-by: David S. Miller
03 Nov, 2011
1 commit
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It's often convenient to be able to release resource from IRQ context.
Make ida_simple_*() use irqsave/restore spin ops so that they are IRQ
safe.Signed-off-by: Tejun Heo
Acked-by: Rusty Russell
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
01 Nov, 2011
13 commits
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As suggested by Andrew Morton in [1] there is better to have most
significant part first in the function name.[1] https://lkml.org/lkml/2011/9/20/22
There is no functional change.
Signed-off-by: Andy Shevchenko
Cc: Jesper Nilsson
Cc: David Howells
Cc: Koichi Yasutake
Cc: Jason Wessel
Cc: Mimi Zohar
Cc: James Morris
Cc: OGAWA Hirofumi
Cc: "John W. Linville"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Commit 84c95c9acf0 ("string: on strstrip(), first remove leading spaces
before running over str") improved the performance of the strim()
function.Unfortunately this changed the semantics of strim() and broke my code.
Before the patch it was possible to use strim() without using the return
value for removing trailing spaces from strings that had either only
blanks or only trailing blanks.Now this does not work any longer for strings that *only* have blanks.
Before patch: " " -> "" (empty string)
After patch: " " -> " " (no change)I think we should remove your patch to restore the old behavior.
The description (lib/string.c):
* Note that the first trailing whitespace is replaced with a %NUL-terminator
=> The first trailing whitespace of a string that only has whitespace
characters is the first whitespaceThe patch restores the old strim() semantics.
Signed-off-by: Michael Holzheu
Cc: Andre Goddard Rosa
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Signed-off-by: Wang Sheng-Hui
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
These variables are only used when CONFIG_HOTPLUG_CPU is enabled, they are
ifdef'ed everywhere else. So don't define them when CONFIG_HOTPLUG_CPU is
not enabled.Signed-off-by: Glauber Costa
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
__bitmap_parse() and __bitmap_parselist() both take a pointer to a kernel
buffer as a parameter and then cast it to a pointer to user buffer for use
in cases when the parameter is_user indicates that the buffer is actually
located in user space. This casting, and the casts in the callers,
results in sparse noise like the following:warning: incorrect type in initializer (different address spaces)
expected char const [noderef] *ubuf
got char const *buf
warning: cast removes address space of expressionSince these casts are intentional, use __force to quiet the noise.
Signed-off-by: H Hartley Sweeten
Cc: Len Brown
Cc: Huang Ying
Cc: Andy Shevchenko
Cc: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
When SPIN_BUG_ON is triggered, the lock owner information is reported.
But it is omitted when spinlock lockup is detected.This information is useful especially on the architectures which don't
implement trigger_all_cpu_backtrace() that is called just after detecting
lockup. So report it and also avoid message format duplication.Signed-off-by: Akinobu Mita
Cc: Ingo Molnar
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Currently termination logic (\0 or \n\0) is hardcoded in _kstrtoull(),
avoid that for code reuse between kstrto*() and simple_strtoull().
Essentially, make them different only in termination logic.simple_strtoull() (and scanf(), BTW) ignores integer overflow, that's a
bug we currently don't have guts to fix, making KSTRTOX_OVERFLOW hack
necessary.Almost forgot: patch shrinks code size by about ~80 bytes on x86_64.
Signed-off-by: Alexey Dobriyan
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Added missing _secs in the help message of config DEFAULT_HUNG_TASK_TIMEOUT.
Signed-off-by: Jiaju Zhang
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
memchr_inv() is mainly used to check whether the whole buffer is filled
with just a specified byte.The function name and prototype are stolen from logfs and the
implementation is from SLUB.Signed-off-by: Akinobu Mita
Acked-by: Christoph Lameter
Acked-by: Pekka Enberg
Cc: Matt Mackall
Acked-by: Joern Engel
Cc: Marcin Slusarz
Cc: Eric Dumazet
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
radix_tree_tag_get()'s BUG (when it sees a tag after saw_unset_tag) was
unsafe and removed in 2.6.34, but the pointless saw_unset_tag left behind.Remove it now, and return 0 as soon as we see unset tag - we already rely
upon the root tag to be correct, returning 0 immediately if it's not set.Signed-off-by: Hugh Dickins
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
There are no modular calls here, so just the minimal header for
the EXPORT_SYMBOL macro will suffice.Signed-off-by: Paul Gortmaker
-
These files were getting the defines for EXPORT_SYMBOL because
device.h was including module.h. But we are going to put an
end to that. So add the proper export.h include now.Signed-off-by: Paul Gortmaker
-
A pending cleanup will mean that module.h won't be implicitly
everywhere anymore. Make sure the modular drivers in md dir
are actually calling out for explicitly in advance.Signed-off-by: Paul Gortmaker
31 Oct, 2011
1 commit
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* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (33 commits)
iommu/core: Remove global iommu_ops and register_iommu
iommu/msm: Use bus_set_iommu instead of register_iommu
iommu/omap: Use bus_set_iommu instead of register_iommu
iommu/vt-d: Use bus_set_iommu instead of register_iommu
iommu/amd: Use bus_set_iommu instead of register_iommu
iommu/core: Use bus->iommu_ops in the iommu-api
iommu/core: Convert iommu_found to iommu_present
iommu/core: Add bus_type parameter to iommu_domain_alloc
Driver core: Add iommu_ops to bus_type
iommu/core: Define iommu_ops and register_iommu only with CONFIG_IOMMU_API
iommu/amd: Fix wrong shift direction
iommu/omap: always provide iommu debug code
iommu/core: let drivers know if an iommu fault handler isn't installed
iommu/core: export iommu_set_fault_handler()
iommu/omap: Fix build error with !IOMMU_SUPPORT
iommu/omap: Migrate to the generic fault report mechanism
iommu/core: Add fault reporting mechanism
iommu/core: Use PAGE_SIZE instead of hard-coded value
iommu/core: use the existing IS_ALIGNED macro
iommu/msm: ->unmap() should return order of unmapped page
...Fixup trivial conflicts in drivers/iommu/Makefile: "move omap iommu to
dedicated iommu folder" vs "Rename the DMAR and INTR_REMAP config
options" just happened to touch lines next to each other.
29 Oct, 2011
1 commit
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* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc: (83 commits)
mmc: fix compile error when CONFIG_BLOCK is not enabled
mmc: core: Cleanup eMMC4.5 conditionals
mmc: omap_hsmmc: if multiblock reads are broken, disable them
mmc: core: add workaround for controllers with broken multiblock reads
mmc: core: Prevent too long response times for suspend
mmc: recognise SDIO cards with SDIO_CCCR_REV 3.00
mmc: sd: Handle SD3.0 cards not supporting UHS-I bus speed mode
mmc: core: support HPI send command
mmc: core: Add cache control for eMMC4.5 device
mmc: core: Modify the timeout value for writing power class
mmc: core: new discard feature support at eMMC v4.5
mmc: core: mmc sanitize feature support for v4.5
mmc: dw_mmc: modify DATA register offset
mmc: sdhci-pci: add flag for devices that can support runtime PM
mmc: omap_hsmmc: ensure pbias configuration is always done
mmc: core: Add Power Off Notify Feature eMMC 4.5
mmc: sdhci-s3c: fix potential NULL dereference
mmc: replace printk with appropriate display macro
mmc: core: Add default timeout value for CMD6
mmc: sdhci-pci: add runtime pm support
...
27 Oct, 2011
4 commits
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mmc_core module needs to use setup_fault_attr() in order
to set fault injection attributes during module load time.Signed-off-by: Per Forlin
Reviewed-by: Akinobu Mita
Signed-off-by: Chris Ball -
This adds support to inject data errors after a completed host transfer.
The mmc core will return error even though the host transfer is successful.
This simple fault injection proved to be very useful to test the
non-blocking error handling in the mmc_blk_issue_rw_rq().
Random faults can also test how the host driver handles pre_req()
and post_req() in case of errors.Signed-off-by: Per Forlin
Acked-by: Akinobu Mita
Reviewed-by: Linus Walleij
Signed-off-by: Chris Ball -
Export symbols should_fail() and fault_create_debugfs_attr() in order
to let modules utilize the fault injection framework.Signed-off-by: Per Forlin
Acked-by: Akinobu Mita
Signed-off-by: Chris Ball -
* 'for-linus' of git://neil.brown.name/md: (34 commits)
md: Fix some bugs in recovery_disabled handling.
md/raid5: fix bug that could result in reads from a failed device.
lib/raid6: Fix filename emitted in generated code
md.c: trivial comment fix
MD: Allow restarting an interrupted incremental recovery.
md: clear In_sync bit on devices added to an active array.
md: add proper write-congestion reporting to RAID1 and RAID10.
md: rename "mdk_personality" to "md_personality"
md/bitmap remove fault injection options.
md/raid5: typedef removal: raid5_conf_t -> struct r5conf
md/raid1: typedef removal: conf_t -> struct r1conf
md/raid10: typedef removal: conf_t -> struct r10conf
md/raid0: typedef removal: raid0_conf_t -> struct r0conf
md/multipath: typedef removal: multipath_conf_t -> struct mpconf
md/linear: typedef removal: linear_conf_t -> struct linear_conf
md/faulty: remove typedef: conf_t -> struct faulty_conf
md/linear: remove typedefs: dev_info_t -> struct dev_info
md: remove typedefs: mirror_info_t -> struct mirror_info
md: remove typedefs: r10bio_t -> struct r10bio and r1bio_t -> struct r1bio
md: remove typedefs: mdk_thread_t -> struct md_thread
...
26 Oct, 2011
2 commits
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* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
llist: Add back llist_add_batch() and llist_del_first() prototypes
sched: Don't use tasklist_lock for debug prints
sched: Warn on rt throttling
sched: Unify the ->cpus_allowed mask copy
sched: Wrap scheduler p->cpus_allowed access
sched: Request for idle balance during nohz idle load balance
sched: Use resched IPI to kick off the nohz idle balance
sched: Fix idle_cpu()
llist: Remove cpu_relax() usage in cmpxchg loops
sched: Convert to struct llist
llist: Add llist_next()
irq_work: Use llist in the struct irq_work logic
llist: Return whether list is empty before adding in llist_add()
llist: Move cpu_relax() to after the cmpxchg()
llist: Remove the platform-dependent NMI checks
llist: Make some llist functions inline
sched, tracing: Show PREEMPT_ACTIVE state in trace_sched_switch
sched: Remove redundant test in check_preempt_tick()
sched: Add documentation for bandwidth control
sched: Return unused runtime on group dequeue
... -
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
rtmutex: Add missing rcu_read_unlock() in debug_rt_mutex_print_deadlock()
lockdep: Comment all warnings
lib: atomic64: Change the type of local lock to raw_spinlock_t
locking, lib/atomic64: Annotate atomic64_lock::lock as raw
locking, x86, iommu: Annotate qi->q_lock as raw
locking, x86, iommu: Annotate irq_2_ir_lock as raw
locking, x86, iommu: Annotate iommu->register_lock as raw
locking, dma, ipu: Annotate bank_lock as raw
locking, ARM: Annotate low level hw locks as raw
locking, drivers/dca: Annotate dca_lock as raw
locking, powerpc: Annotate uic->lock as raw
locking, x86: mce: Annotate cmci_discover_lock as raw
locking, ACPI: Annotate c3_lock as raw
locking, oprofile: Annotate oprofilefs lock as raw
locking, video: Annotate vga console lock as raw
locking, latencytop: Annotate latency_lock as raw
locking, timer_stats: Annotate table_lock as raw
locking, rwsem: Annotate inner lock as raw
locking, semaphores: Annotate inner lock as raw
locking, sched: Annotate thread_group_cputimer as raw
...Fix up conflicts in kernel/posix-cpu-timers.c manually: making
cputimer->cputime a raw lock conflicted with the ABBA fix in commit
bcd5cff7216f ("cputimer: Cure lock inversion").
25 Oct, 2011
5 commits
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* 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (38 commits)
mm: memory hotplug: Check if pages are correctly reserved on a per-section basis
Revert "memory hotplug: Correct page reservation checking"
Update email address for stable patch submission
dynamic_debug: fix undefined reference to `__netdev_printk'
dynamic_debug: use a single printk() to emit messages
dynamic_debug: remove num_enabled accounting
dynamic_debug: consolidate repetitive struct _ddebug descriptor definitions
uio: Support physical addresses >32 bits on 32-bit systems
sysfs: add unsigned long cast to prevent compile warning
drivers: base: print rejected matches with DEBUG_DRIVER
memory hotplug: Correct page reservation checking
memory hotplug: Refuse to add unaligned memory regions
remove the messy code file Documentation/zh_CN/SubmitChecklist
ARM: mxc: convert device creation to use platform_device_register_full
new helper to create platform devices with dma mask
docs/driver-model: Update device class docs
docs/driver-model: Document device.groups
kobj_uevent: Ignore if some listeners cannot handle message
dynamic_debug: make netif_dbg() call __netdev_printk()
dynamic_debug: make netdev_dbg() call __netdev_printk()
... -
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (59 commits)
MAINTAINERS: linux-m32r is moderated for non-subscribers
linux@lists.openrisc.net is moderated for non-subscribers
Drop default from "DM365 codec select" choice
parisc: Kconfig: cleanup Kernel page size default
Kconfig: remove redundant CONFIG_ prefix on two symbols
cris: remove arch/cris/arch-v32/lib/nand_init.S
microblaze: add missing CONFIG_ prefixes
h8300: drop puzzling Kconfig dependencies
MAINTAINERS: microblaze-uclinux@itee.uq.edu.au is moderated for non-subscribers
tty: drop superfluous dependency in Kconfig
ARM: mxc: fix Kconfig typo 'i.MX51'
Fix file references in Kconfig files
aic7xxx: fix Kconfig references to READMEs
Fix file references in drivers/ide/
thinkpad_acpi: Fix printk typo 'bluestooth'
bcmring: drop commented out line in Kconfig
btmrvl_sdio: fix typo 'btmrvl_sdio_sd6888'
doc: raw1394: Trivial typo fix
CIFS: Don't free volume_info->UNC until we are entirely done with it.
treewide: Correct spelling of successfully in comments
... -
* 'for-linus' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm: (81 commits)
ARM: 7133/1: SMP: fix per cpu timer setup before the cpu is marked online
ARM: 7129/1: Add __arm_ioremap_exec for mapping external memory as MT_MEMORY
ARM: 7136/1: pl330: Fix a race condition
ARM: smp: fix clipping of number of CPUs
ARM: 7137/1: Fix error upon adding LL debug
ARM: Add a few machine types to mach-types
ARM: 7130/1: dev_archdata: add private iommu extension
ARM: 7125/1: Add unwinding annotations for 64bit division functions
ARM: 7120/1: remove bashism in check for multiple zreladdrs
ARM: 7118/1: rename temp variable in read*_relaxed()
ARM: 6217/4: mach-realview: expose PB1176 ROM using physmap and map_rom
ARM: 7098/1: kdump: copy kernel relocation code at the kexec prepare stage
ARM: 7062/1: cache: detect PIPT I-cache using CTR
ARM: platform fixups: remove mdesc argument to fixup function
ARM: 7017/1: Use generic BUG() handler
ARM: 7102/1: mach-integrator: update defconfig
ARM: 7087/2: mach-integrator: get timer frequency from clock
ARM: 7086/2: mach-integrator: modernize clock event registration
ARM: 7085/2: mach-integrator: clockevent supports oneshot mode
ARM: 7084/1: mach-integrator: retire some timer macros
... -
* 'next' of git://selinuxproject.org/~jmorris/linux-security: (95 commits)
TOMOYO: Fix incomplete read after seek.
Smack: allow to access /smack/access as normal user
TOMOYO: Fix unused kernel config option.
Smack: fix: invalid length set for the result of /smack/access
Smack: compilation fix
Smack: fix for /smack/access output, use string instead of byte
Smack: domain transition protections (v3)
Smack: Provide information for UDS getsockopt(SO_PEERCRED)
Smack: Clean up comments
Smack: Repair processing of fcntl
Smack: Rule list lookup performance
Smack: check permissions from user space (v2)
TOMOYO: Fix quota and garbage collector.
TOMOYO: Remove redundant tasklist_lock.
TOMOYO: Fix domain transition failure warning.
TOMOYO: Remove tomoyo_policy_memory_lock spinlock.
TOMOYO: Simplify garbage collector.
TOMOYO: Fix make namespacecheck warnings.
target: check hex2bin result
encrypted-keys: check hex2bin result
... -
…'pgt' (early part) and 'smp' into for-linus
21 Oct, 2011
1 commit
-
…mu/fault-reporting' and 'api/iommu-ops-per-bus' into next
Conflicts:
drivers/iommu/amd_iommu.c
drivers/iommu/iommu.c
20 Oct, 2011
1 commit
-
The files were renamed in commit cc4589ebf; fix the name in the file
itself.Signed-off-by: Dan McGee
Signed-off-by: NeilBrown
19 Oct, 2011
3 commits
-
Dynamic debug recently added support for netdev_printk. It uses
__netdev_printk() to support this functionality. However, when CONFIG_NET
is not set, we get the following error:lib/built-in.o: In function `__dynamic_netdev_dbg':
(.text+0x9fda): undefined reference to `__netdev_printk'Fix this by making the call to netdev_printk() contingent upon CONFIG_NET.
We could have fixed this by defining netdev_printk() to a 'no-op' in the
!CONFIG_NET case. However, this is not consistent with how the networking
layer uses netdev_printk. For example, CONFIG_NET is not set,
netdev_printk() does not have a 'no-op' definition defined.Signed-off-by: Jason Baron
Acked-by: Randy Dunlap
Acked-by: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Greg Kroah-Hartman -
We were using KERN_CONT to combine messages with their prefix. However,
KERN_CONT is not smp safe, in the sense that it can interleave messages.
This interleaving can result in printks coming out at the wrong loglevel.
With the high frequency of printks that dynamic debug can produce this is
not desirable.So make dynamic_emit_prefix() fill a char buf[64] instead of doing a
printk directly. If we enable printing out of function, module, line, or
pid info, they are placed in this 64 byte buffer. In my testing 64 bytes
was enough size to fulfill all requests. Even if it's not, we can match
up the printk itself to see where it's from, so to me this is no big deal.[akpm@linux-foundation.org: convert dangerous macro to C]
Signed-off-by: Jason Baron
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Greg Kroah-Hartman -
The num_enabled accounting isn't actually used anywhere - remove them.
Signed-off-by: Jason Baron
Cc: Arnd Bergmann
Signed-off-by: Andrew Morton
Signed-off-by: Greg Kroah-Hartman
06 Oct, 2011
1 commit
-
This task is preparatory for the migrate_disable() implementation, but
stands on its own and provides a cleanup.It currently only converts those sites required for task-placement.
Kosaki-san once mentioned replacing cpus_allowed with a proper
cpumask_t instead of the NR_CPUS sized array it currently is, that
would also require something like this.Signed-off-by: Peter Zijlstra
Acked-by: Thomas Gleixner
Cc: KOSAKI Motohiro
Link: http://lkml.kernel.org/n/tip-e42skvaddos99psip0vce41o@git.kernel.org
Signed-off-by: Ingo Molnar
04 Oct, 2011
3 commits
-
Initial benchmarks show they're a net loss:
$ for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo performance > $i; done
$ echo 4096 32000 64 128 > /proc/sys/kernel/sem
$ ./sembench -t 2048 -w 1900 -o 0Pre:
run time 30 seconds 778936 worker burns per second
run time 30 seconds 912190 worker burns per second
run time 30 seconds 817506 worker burns per second
run time 30 seconds 830870 worker burns per second
run time 30 seconds 845056 worker burns per secondPost:
run time 30 seconds 905920 worker burns per second
run time 30 seconds 849046 worker burns per second
run time 30 seconds 886286 worker burns per second
run time 30 seconds 822320 worker burns per second
run time 30 seconds 900283 worker burns per secondSo about 4% faster. (!)
cpu_relax() stalls the pipeline, therefore, when used in a tight loop
it has the following benefits:- allows SMT siblings to have a go;
- reduces pressure on the CPU interconnect.However, cmpxchg loops are unfair and thus have unbounded completion
time, therefore we should avoid getting in such heavily contended
situations where the above benefits make any difference.A typical cmpxchg loop should not go round more than a handfull of
times at worst, therefore adding extra delays just slows things down.Since the llist primitives are new, there aren't any bad users yet,
and we should avoid growing them. Heavily contended sites should
generally be better off using the ticket locks for serialization since
they provide bounded completion times (fifo-fair over the cpus).Signed-off-by: Peter Zijlstra
Cc: Huang Ying
Cc: Andrew Morton
Link: http://lkml.kernel.org/r/1315836358.26517.43.camel@twins
Signed-off-by: Ingo Molnar -
Extend the llist_add*() functions to return a success indicator, this
allows us in the scheduler code to send an IPI if the queue was empty.( There's no effect on existing users, because the list_add_xxx() functions
are inline, thus this will be optimized out by the compiler if not used
by callers. )Signed-off-by: Huang Ying
Cc: Mathieu Desnoyers
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/1315461646-1379-5-git-send-email-ying.huang@intel.com
Signed-off-by: Ingo Molnar -
If in llist_add()/etc. functions the first cmpxchg() call succeeds, it is
not necessary to use cpu_relax() before the cmpxchg(). So cpu_relax() in
a busy loop involving cmpxchg() should go after cmpxchg() instead of before
that.This patch fixes this for all involved llist functions.
Signed-off-by: Huang Ying
Acked-by: Mathieu Desnoyers
Signed-off-by: Peter Zijlstra
Link: http://lkml.kernel.org/r/1315461646-1379-4-git-send-email-ying.huang@intel.com
Signed-off-by: Ingo Molnar
