We currently run class->post_schedule() outside of the rq->lock, which
means that we need to test for the need to post_schedule outside of
the lock to avoid a forced reacquistion. This is currently not a problem
as we only look at rq->rt.overloaded. However, we want to enhance this
going forward to look at more state to reduce the need to post_schedule to
a bare minimum set. Therefore, we introduce a new member-func called
needs_post_schedule() which tests for the post_schedule condtion without
actually performing the work. Therefore it is safe to call this
function before the rq->lock is released, because we are guaranteed not
to drop the lock at an intermediate point (such as what post_schedule()
may do).
We will use this later in the series
[ rostedt: removed paranoid BUG_ON ]
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
double_lock balance() currently favors logically lower cpus since they
often do not have to release their own lock to acquire a second lock.
The result is that logically higher cpus can get starved when there is
a lot of pressure on the RQs. This can result in higher latencies on
higher cpu-ids.
This patch makes the algorithm more fair by forcing all paths to have
to release both locks before acquiring them again. Since callsites to
double_lock_balance already consider it a potential preemption/reschedule
point, they have the proper logic to recheck for atomicity violations.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
git-id c4acb2c066 attempted to limit
newidle critical section length by stopping after at least one task
was moved. Further investigation has shown that there are other
paths nested further inside the algorithm which still remain that allow
long latencies to occur with newidle balancing. This patch applies
the same technique inside balance_tasks() to limit the duration of
this optional balancing operation.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
CC: Nick Piggin <npiggin@suse.de>
There is no sense in wasting time trying to push a task away that
cannot move anywhere else. We gain no benefit from trying to push
other tasks at this point, so if the task being woken up is non
migratable, just skip the whole operation. This reduces overhead
in the wakeup path for certain tasks.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
We currently take the rq->lock for every cpu in an overload state during
pull_rt_tasks(). However, we now have enough information via the
highest_prio.[curr|next] fields to determine if there is any tasks of
interest to warrant the overhead of the rq->lock, before we actually take
it. So we use this information to reduce lock contention during the
pull for the case where the source-rq doesnt have tasks that preempt
the current task.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
highest_prio.curr is actually a more accurate way to keep track of
the pull_rt_task() threshold since it is always up to date, even
if the "next" task migrates during double_lock. Therefore, stop
looking at the "next" task object and simply use the highest_prio.curr.
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
We will use this later in the series to reduce the amount of rq-lock
contention during a pull operation
Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Impact: fix section mismatch warning
Commit b2bb855491 ("x86: Remove cpumask games
in x86/kernel/cpu/intel_cacheinfo.c") introduced get_cpu_leaves(), which
references __cpuinit cpuid4_cache_lookup().
Mark get_cpu_leaves() with a __cpuinit annotation.
Signed-off-by: Sergio Luis <sergio@larces.uece.br>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: build fix
lguest can be built as a module and makes use of this new symbol:
ERROR: "vector_used_by_percpu_irq" [drivers/lguest/lg.ko] undefined!
export it.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
These commits:
commit 95d313cf1c
Author: Mike Travis <travis@sgi.com>
Date: Tue Dec 16 17:33:54 2008 -0800
x86: Add cpu_mask_to_apicid_and
and
commit 6eeb7c5a99
Author: Mike Travis <travis@sgi.com>
Date: Tue Dec 16 17:33:55 2008 -0800
x86: update add-cpu_mask_to_apicid_and to use struct cpumask*
broke interrupt delivery on x2apic platforms. As x2apic cluster mode uses
logical delivery mode, we need to use logical apicid instead of physical apicid
in x2apic_cpu_mask_to_apicid_and()
Impact: fixes the broken interrupt delivery issue on generic x2apic platforms.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Acked-by: Mike Travis <travis@sgi.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Andrew Morton reported:
> kernel/sched.c: In function 'schedule':
> kernel/sched.c:3679: warning: 'active_balance' may be used uninitialized in this function
>
> This warning is correct - the code is buggy.
In sched.c load_balance_newidle, there's real potential use of
uninitialised variable - fix it.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix lguest, clean up
32-bit lguest used used_vectors to record vectors, but that model of
allocating vectors changed and got broken, after we changed vector
allocation to a per_cpu array.
Try enable that for 64bit, and the array is used for all vectors that
are not managed by vector_irq per_cpu array.
Also kill system_vectors[], that is now a duplication of the
used_vectors bitmap.
[ merged in cpus4096 due to io_apic.c cpumask changes. ]
[ -v2, fix build failure ]
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
this warning:
arch/x86/kernel/io_apic.c: In function ‘ir_set_msi_irq_affinity’:
arch/x86/kernel/io_apic.c:3373: warning: ‘cfg’ may be used uninitialized in this function
triggers because the variable was truly uninitialized. We'd crash on
entering this code.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix cpumask conversion bug
this warning:
kernel/sched.c: In function ‘find_busiest_group’:
kernel/sched.c:3429: warning: passing argument 1 of ‘__first_cpu’ from incompatible pointer type
shows that we forgot to convert a new patch to the new cpumask APIs.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: change task balancing to save power more agressively
Add SD_BALANCE_NEWIDLE flag at MC level and CPU level
if sched_mc is set. This helps power savings and
will not affect performance when sched_mc=0
Ingo and Mike Galbraith have optimised the SD flags by
removing SD_BALANCE_NEWIDLE at MC and CPU level. This
helps performance but hurts power savings since this
slows down task consolidation by reducing the number
of times load_balance is run.
sched: fine-tune SD_MC_INIT
commit 1480098470
Author: Mike Galbraith <efault@gmx.de>
Date: Fri Nov 7 15:26:50 2008 +0100
sched: re-tune balancing -- revert
commit 9fcd18c9e6
Author: Ingo Molnar <mingo@elte.hu>
Date: Wed Nov 5 16:52:08 2008 +0100
This patch selectively enables SD_BALANCE_NEWIDLE flag
only when sched_mc is set to 1 or 2. This helps power savings
by task consolidation and also does not hurt performance at
sched_mc=0 where all power saving optimisations are turned off.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: tweak task balancing to save power more agressively
Active load balancing is a process by which migration thread
is woken up on the target CPU in order to pull current
running task on another package into this newly idle
package.
This method is already in use with normal load_balance(),
this patch introduces this method to new idle cpus when
sched_mc is set to POWERSAVINGS_BALANCE_WAKEUP.
This logic provides effective consolidation of short running
daemon jobs in a almost idle system
The side effect of this patch may be ping-ponging of tasks
if the system is moderately utilised. May need to adjust the
iterations before triggering.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: tweak task wakeup to save power more agressively
Preferred wakeup cpu (from a semi idle package) has been
nominated in find_busiest_group() in the previous patch. Use
this information in sched_mc_preferred_wakeup_cpu in function
wake_idle() to bias task wakeups if the following conditions
are satisfied:
- The present cpu that is trying to wakeup the process is
idle and waking the target process on this cpu will
potentially wakeup a completely idle package
- The previous cpu on which the target process ran is
also idle and hence selecting the previous cpu may
wakeup a semi idle cpu package
- The task being woken up is allowed to run in the
nominated cpu (cpu affinity and restrictions)
Basically if both the current cpu and the previous cpu on
which the task ran is idle, select the nominated cpu from semi
idle cpu package for running the new task that is waking up.
Cache hotness is considered since the actual biasing happens
in wake_idle() only if the application is cache cold.
This technique will effectively move short running bursty jobs in
a mostly idle system.
Wakeup biasing for power savings gets automatically disabled if
system utilisation increases due to the fact that the probability
of finding both this_cpu and prev_cpu idle decreases.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: extend load-balancing code (no change in behavior yet)
When the system utilisation is low and more cpus are idle,
then the process waking up from sleep should prefer to
wakeup an idle cpu from semi-idle cpu package (multi core
package) rather than a completely idle cpu package which
would waste power.
Use the sched_mc balance logic in find_busiest_group() to
nominate a preferred wakeup cpu.
This info can be stored in appropriate sched_domain, but
updating this info in all copies of sched_domain is not
practical. Hence this information is stored in root_domain
struct which is one copy per partitioned sched domain.
The root_domain can be accessed from each cpu's runqueue
and there is one copy per partitioned sched domain.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: change load-balancing direction to match that of irqbalanced
Just in case two groups have identical load, prefer to move load to lower
logical cpu number rather than the present logic of moving to higher logical
number.
find_busiest_group() tries to look for a group_leader that has spare capacity
to take more tasks and freeup an appropriate least loaded group. Just in case
there is a tie and the load is equal, then the group with higher logical number
is favoured. This conflicts with user space irqbalance daemon that will move
interrupts to lower logical number if the system utilisation is very low.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: extend range of /sys/devices/system/cpu/sched_mc_power_savings
Currently the sched_mc/smt_power_savings variable is a boolean,
which either enables or disables topology based power savings.
This patch extends the behaviour of the variable from boolean to
multivalued, such that based on the value, we decide how
aggressively do we want to perform powersavings balance at
appropriate sched domain based on topology.
Variable levels of power saving tunable would benefit end user to
match the required level of power savings vs performance
trade-off depending on the system configuration and workloads.
This version makes the sched_mc_power_savings global variable to
take more values (0,1,2). Later versions can have a single
tunable called sched_power_savings instead of
sched_{mc,smt}_power_savings.
Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
BALANCE_FOR_MC_POWER and similar macros defined in sched.h are
not constants and have various condition checks and significant
amount of code that is not suitable to be contain in a macro.
Also there could be side effects on the expressions passed to
some of them like test_sd_parent().
This patch converts all complex macros related to power savings
balance to inline functions.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add new boot parameter
Use possible_cpus=NUM kernel parameter to extend the number of possible
cpus.
The ability to HOTPLUG ON cpus that are "possible" but not "present" is
dealt with in a later patch.
Signed-off-by: Mike Travis <travis@sgi.com>
Impact: fix potential APIC crash
In determining the destination apicid, there are usually three cpumasks
that are considered: the incoming cpumask arg, cfg->domain and the
cpu_online_mask. Since we are just introducing the cpu_mask_to_apicid_and
function, make sure it includes the cpu_online_mask in it's evaluation.
[Added with this patch.]
There are two io_apic.c functions that did not previously use the
cpu_online_mask: setup_IO_APIC_irq and msi_compose_msg. Both of these
simply used cpu_mask_to_apicid(cfg->domain & TARGET_CPUS), and all but
one arch (NUMAQ[*]) returns only online cpus in the TARGET_CPUS mask,
so the behavior is identical for all cases.
[*: NUMAQ bug?]
Note that alloc_cpumask_var is only used for the 32-bit cases where
it's highly likely that the cpumask set size will be small and therefore
CPUMASK_OFFSTACK=n. But if that's not the case, failing the allocate
will cause the same return value as the default.
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This done for conflict prevention: we merge it into the cpus4096 tree
because upcoming cpumask changes will touch apic.c that would collide
with x86/apic otherwise.
* 'i2c-fixes' of git://aeryn.fluff.org.uk/bjdooks/linux:
i2c-s3c2410: fix check for being in suspend.
i2c-cpm: Detect and report NAK right away instead of timing out
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6:
USB: pl2303: add id for Hewlett-Packard LD220-HP POS pole display
USB: set correct configuration in probe of ti_usb_3410_5052
USB: add 5372:2303 to pl2303
USB: skip Set-Interface(0) if already in altsetting 0
USB: fix comment about endianness of descriptors
USB: Documentation/usb/gadget_serial.txt: update to match driver use_acm behaviour
usbmon: drop bogus 0t from usbmon.txt
USB: gadget: fix rndis working at high speed
USB: ftdi_sio: Adding Ewert Energy System's CANdapter PID
USB: tty: SprogII DCC controller identifiers
usb-storage: update unusual_devs entry for Nokia 5310
USB: Unusual devs patch for Nokia 3500c
USB: storage: unusual_devs.h: Nokia 3109c addition
USB: fix problem with usbtmc driver not loading properly
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6:
STAGING: Move staging drivers back to staging-specific menu
driver core: add newlines to debugging enabled/disabled messages
xilinx_hwicap: remove improper wording in license statement
driver core: fix using 'ret' variable in unregister_dynamic_debug_module
While testing a kernel with memory poisoning enabled, I saw some warnings
about the redzone getting clobbered when chasing DFS referrals. The
buffer allocation for the unicode converted version of the searchName is
too small and needs to take null termination into account.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Acked-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'merge' of git://git.kernel.org/pub/scm/linux/kernel/git/galak/powerpc:
powerpc: Fix corruption error in rh_alloc_fixed()
powerpc/fsl-booke: Fix the miss interrupt restore
Both messages are missing the newline and thus dmesg output gets
scrambled.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
GPLv2 doesn't allow additional restrictions to be imposed on any
code, so this wording needs to be removed from these files.
Signed-off-by: Stephen Neuendorffer <stephen.neuendorffer@xilinx.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The 'ret' variable is assigned, but not used in the return statement. Fix this.
Signed-off-by: Johann Felix Soden <johfel@users.sourceforge.net>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add id for the Hewlett-Packard LD220-HP POS pole display.
Bus 002 Device 002: ID 03f0:3524 Hewlett-Packard
Signed-off-by: Mike Provencher <mike.provencher@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This driver transfers firmware. It may just as well set the correct
configuration.
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch adds the "Superial" USB-Serial converter to pl2303 so that it
is detected, by the correct driver. Adds the relevant vendor:product
(5372:2303) to the device tables in pl2303.c & pl2303.h. The patch has
been tested against 2.6.24-22-generic.
Signed-off-by: Matthew D Arnold <matthew.arnold-1@uts.edu.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When a driver unbinds from an interface, usbcore always sends a
Set-Interface request to reinstall altsetting 0. Unforunately, quite
a few devices have buggy firmware that crashes when it receives this
request.
To avoid such problems, this patch (as1180) arranges to send the
Set-Interface request only when the interface is not already in
altsetting 0.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch fixes a comment and clarifies the documentation about the
endianness of descriptors. The current policy is that descriptors will
be little-endian at the API even on big-endian systems; however the
/proc/bus/usb API predates this policy and presents descriptors with
some multibyte fields byte-swapped.
Signed-off-by: Phil Endecott <usb_endian_patch@chezphil.org>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Commit 7bb5ea54 (usb gadget serial: use composite gadget framework)
changed the default for the use_acm parameter from 0 to 1.
Update the documentation to match.
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Acked-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The example is incorrect: there is no 0t socket (the '1t' format has no
bus number in it). Also, correct the broken sentence for USB Tag.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix a bug specific to highspeed mode in the recently updated RNDIS
support: it wasn't setting up the high speed notification endpoint,
which prevented high speed RNDIS links from working.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Tested-by: Anand Gadiyar <gadiyar@ti.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Someone on rmweb reminded me this had been overlooked from ages ago..
Add the identifiers for the Sprog II USB. This is a DCC control interface
using the FTDI-SIO hardware: http://www.sprog-dcc.co.uk/. People have been
using it with insmod options for ages, this just puts it into the driver
data.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1179) updates the unusual_devs entry for Nokia's 5310
phone to include a more recent firmware revision.
This fixes Bugzilla #12099.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Robson Roberto Souza Peixoto <robsonpeixoto@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2.6.26(.x, cannot remember) could handle the microSD card in my Nokia
3109c attached via USB as mass storage, 2.6.27(.x, up to and included
2.6.27.8) cannot. Please find the attached patch which fixes this
regression, and a copy of /proc/bus/usb/devices with my phone plugged in
running with this patch on Frugalware.
T: Bus=02 Lev=01 Prnt=01 Port=01 Cnt=02 Dev#= 4 Spd=12 MxCh= 0
D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
P: Vendor=0421 ProdID=0063 Rev= 6.01
S: Manufacturer=Nokia
S: Product=Nokia 3109c
S: SerialNumber=359561013742570
C:* #Ifs= 1 Cfg#= 1 Atr=c0 MxPwr=100mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
E: Ad=81(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms
E: Ad=01(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms
From: CSÉCSY László <boobaa@frugalware.org>
Cc: Phil Dibowitz <phil@ipom.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
