random uvesafb failures were reported against Gentoo:
http://bugs.gentoo.org/show_bug.cgi?id=222799
and Mihai Moldovan bisected it back to:
> 8f4d37ec07 is first bad commit
> commit 8f4d37ec07
> Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Date: Fri Jan 25 21:08:29 2008 +0100
>
> sched: high-res preemption tick
Linus suspected it to be hrtick + vm86 interaction and observed:
> Btw, Peter, Ingo: I think that commit is doing bad things. They aren't
> _incorrect_ per se, but they are definitely bad.
>
> Why?
>
> Using random _TIF_WORK_MASK flags is really impolite for doing
> "scheduling" work. There's a reason that arch/x86/kernel/entry_32.S
> special-cases the _TIF_NEED_RESCHED flag: we don't want to exit out of
> vm86 mode unnecessarily.
>
> See the "work_notifysig_v86" label, and how it does that
> "save_v86_state()" thing etc etc.
Right, I never liked having to fiddle with those TIF flags. Initially I
needed it because the hrtimer base lock could not nest in the rq lock.
That however is fixed these days.
Currently the only reason left to fiddle with the TIF flags is remote
wakeups. We cannot program a remote cpu's hrtimer. I've been thinking
about using the new and improved IPI function call stuff to implement
hrtimer_start_on().
However that does require that smp_call_function_single(.wait=0) works
from interrupt context - /me looks at the latest series from Jens - Yes
that does seem to be supported, good.
Here's a stab at cleaning this stuff up ...
Mihai reported test success as well.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Mihai Moldovan <ionic@ionic.de>
Cc: Michal Januszewski <spock@gentoo.org>
Cc: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Rename CPUMASK_VAR --> CPUMASK_PTR (and simplify)
* Fix a semantic error in CPUMASK_ALLOC
* Add a bit of commentry to cpumask.h
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
so NUMAQ can use that to call numaq_pre_time_init()
This allows us to remove a NUMAQ special from arch/x86/kernel/setup.c.
(and paves the way to remove the NUMAQ subarch)
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
add these new x86_quirks methods:
int *mpc_record;
int (*mpc_apic_id)(struct mpc_config_processor *m);
void (*mpc_oem_bus_info)(struct mpc_config_bus *m, char *name);
void (*mpc_oem_pci_bus)(struct mpc_config_bus *m);
void (*smp_read_mpc_oem)(struct mp_config_oemtable *oemtable,
unsigned short oemsize);
... and move NUMAQ related mps table handling to numaq_32.c.
also move the call to smp_read_mpc_oem() to smp_read_mpc() directly.
Should not change functionality, albeit it would be nice to get it
tested on real NUMAQ as well ...
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
introduce x86_quirks array of boot-time quirk methods.
No change in functionality intended.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add size table functions for qdiscs and calculate packet size in
qdisc_enqueue().
Based on patch by Patrick McHardy
http://marc.info/?l=linux-netdev&m=115201979221729&w=2
Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>
Use sockaddr_storage{} for generic socket address storage
and ensures proper alignment.
Use sockaddr{} for pointers to omit several casts.
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Remove redundant checks when setting eff_sacks and make the number of SACKs a
compile time constant. Now that the options code knows how many SACK blocks can
fit in the header, we don't need to have the SACK code guessing at it.
Signed-off-by: Adam Langley <agl@imperialviolet.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This should fix the following bugs:
* Connections with MD5 signatures produce invalid packets whenever SACK
options are included
* MD5 signatures are counted twice in the MSS calculations
Behaviour changes:
* A SYN with MD5 + SACK + TS elicits a SYNACK with MD5 + SACK
This is because we can't fit any SACK blocks in a packet with MD5 + TS
options. There was discussion about disabling SACK rather than TS in
order to fit in better with old, buggy kernels, but that was deemed to
be unnecessary.
* SYNs with MD5 don't include a TS option
See above.
Additionally, it removes a bunch of duplicated logic for calculating options,
which should help avoid these sort of issues in the future.
Signed-off-by: Adam Langley <agl@imperialviolet.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, the MD5 code assumes that the SKBs are linear and, in the case
that they aren't, happily goes off and hashes off the end of the SKB and
into random memory.
Reported by Stephen Hemminger in [1]. Advice thanks to Stephen and Evgeniy
Polyakov. Also includes a couple of missed route_caps from Stephen's patch
in [2].
[1] http://marc.info/?l=linux-netdev&m=121445989106145&w=2
[2] http://marc.info/?l=linux-netdev&m=121459157816964&w=2
Signed-off-by: Adam Langley <agl@imperialviolet.org>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some of the metrics (RTT, RTTVAR and RTAX_RTO_MIN) are stored in
kernel units (jiffies) and this leaks out through the netlink API to
user space where the units for jiffies are unknown.
This patches changes the kernel to convert to/from milliseconds. This
changes the ABI, but milliseconds seemed like the most natural unit
for these parameters. Values available via syscall in
/proc/net/rt_cache and netlink will be in milliseconds.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Idea is from Patrick McHardy.
Instead of managing the list of qdiscs on the device level, manage it
in the root qdisc of a netdev_queue. This solves all kinds of
visibility issues during qdisc destruction.
The way to iterate over all qdiscs of a netdev_queue is to visit
the netdev_queue->qdisc, and then traverse it's list.
The only special case is to ignore builting qdiscs at the root when
dumping or doing a qdisc_lookup(). That was not needed previously
because builtin qdiscs were not added to the device's qdisc_list.
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a SW_DOCK switch to input.h. ACPI docks currently send their docking
status as a uevent, but not all docks are ACPI or correspond to a device.
In that case, it makes more sense to simply generate an input event on
docking or undocking.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Add a new switch type to the input API for reporting microphone
insertion. This will be used by the ALSA jack reporting API.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
The u32_list is just an indirect way of maintaining a reference
to a U32 node on a per-qdisc basis.
Just add an explicit node pointer for u32 to struct Qdisc an do
away with this global list.
Signed-off-by: David S. Miller <davem@davemloft.net>
Add new sockopt to reserve some headroom in the mmaped ring frames in
front of the packet payload. This can be used f.i. when the VLAN header
needs to be (re)constructed to avoid moving the entire payload.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a directory for x86 arch under debugfs. Can be used to accumulate all
x86 specific debugfs files.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
As 256 entries are needed, aligning to a 256-entry boundary is
sufficient and still guarantees the single pte table requirement.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
It's not used anywhere outside its single referencing file.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
* Provide a generic set of CPUMASK_ALLOC macros patterned after the
SCHED_CPUMASK_ALLOC macros. This is used where multiple cpumask_t
variables are declared on the stack to reduce the amount of stack
space required.
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* This patch replaces the dangerous lvalue version of cpumask_of_cpu
with new cpumask_of_cpu_ptr macros. These are patterned after the
node_to_cpumask_ptr macros.
In general terms, if there is a cpumask_of_cpu_map[] then a pointer to
the cpumask_of_cpu_map[cpu] entry is used. The cpumask_of_cpu_map
is provided when there is a large NR_CPUS count, reducing
greatly the amount of code generated and stack space used for
cpumask_of_cpu(). The pointer to the cpumask_t value is needed for
calling set_cpus_allowed_ptr() to reduce the amount of stack space
needed to pass the cpumask_t value.
If there isn't a cpumask_of_cpu_map[], then a temporary variable is
declared and filled in with value from cpumask_of_cpu(cpu) as well as
a pointer variable pointing to this temporary variable. Afterwards,
the pointer is used to reference the cpumask value. The compiler
will optimize out the extra dereference through the pointer as well
as the stack space used for the pointer, resulting in identical code.
A good example of the orthogonal usages is in net/sunrpc/svc.c:
case SVC_POOL_PERCPU:
{
unsigned int cpu = m->pool_to[pidx];
cpumask_of_cpu_ptr(cpumask, cpu);
*oldmask = current->cpus_allowed;
set_cpus_allowed_ptr(current, cpumask);
return 1;
}
case SVC_POOL_PERNODE:
{
unsigned int node = m->pool_to[pidx];
node_to_cpumask_ptr(nodecpumask, node);
*oldmask = current->cpus_allowed;
set_cpus_allowed_ptr(current, nodecpumask);
return 1;
}
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Declaring x86 traps under one hood.
Declaring x86 do_traps before defining them.
Signed-off-by: Jaswinder Singh <jaswinder@infradead.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The force_mwait variable iss defined either in
arch/x86/kernel/cpu/amd.c or in arch/x86/kernel/setup_64.c, but it is
only initialized and used in arch/x86/kernel/process.c. This patch
moves the declaration to arch/x86/kernel/process.c.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: michael@free-electrons.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Jack Ren and Eric Miao tracked down the following long standing
problem in the NOHZ code:
scheduler switch to idle task
enable interrupts
Window starts here
----> interrupt happens (does not set NEED_RESCHED)
irq_exit() stops the tick
----> interrupt happens (does set NEED_RESCHED)
return from schedule()
cpu_idle(): preempt_disable();
Window ends here
The interrupts can happen at any point inside the race window. The
first interrupt stops the tick, the second one causes the scheduler to
rerun and switch away from idle again and we end up with the tick
disabled.
The fact that it needs two interrupts where the first one does not set
NEED_RESCHED and the second one does made the bug obscure and extremly
hard to reproduce and analyse. Kudos to Jack and Eric.
Solution: Limit the NOHZ functionality to the idle loop to make sure
that we can not run into such a situation ever again.
cpu_idle()
{
preempt_disable();
while(1) {
tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we
are in the idle loop
while (!need_resched())
halt();
tick_nohz_restart_sched_tick(); <- disables NOHZ mode
preempt_enable_no_resched();
schedule();
preempt_disable();
}
}
In hindsight we should have done this forever, but ...
/me grabs a large brown paperbag.
Debugged-by: Jack Ren <jack.ren@marvell.com>,
Debugged-by: eric miao <eric.y.miao@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Fallout from commit 33185c504f ("x86:
merge signal_32/64.h")
Thanks to Dick Streefland who provided an useful testcase on
http://lkml.org/lkml/2008/3/17/205 (only applicable to 2.6.24.x), that
helped a lot as a deterministic way to bisect an issue that leaded to
this fix.
Signed-off-by: Herton Ronaldo Krzesinski <herton@mandriva.com.br>
Signed-off-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br>
Cc: Roland McGrath <roland@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This is v2, it's a little deference from v1 that I
had send to lkml.
use ACCESS_ONCE
use rcu_batch_after/rcu_batch_before for batch # comparison.
rcutorture test result:
(hotplugs: do cpu-online/offline once per second)
No CONFIG_NO_HZ: OK, 12hours
No CONFIG_NO_HZ, hotplugs: OK, 12hours
CONFIG_NO_HZ=y: OK, 24hours
CONFIG_NO_HZ=y, hotplugs: Failed.
(Failed also without my patch applied, exactly the same bug occurred,
http://lkml.org/lkml/2008/7/3/24)
v1's email thread:
http://lkml.org/lkml/2008/6/2/539
v1's description:
The code/algorithm of the implement of current callbacks-processing
is very efficient and technical. But when I studied it and I found
a disadvantage:
In multi-CPU systems, when a new RCU callback is being
queued(call_rcu[_bh]), this callback will be invoked after the grace
period for the batch with batch number = rcp->cur+2 has completed
very very likely in current implement. Actually, this callback can be
invoked after the grace period for the batch with
batch number = rcp->cur+1 has completed. The delay of invocation means
that latency of synchronize_rcu() is extended. But more important thing
is that the callbacks usually free memory, and these works are delayed
too! it's necessary for reclaimer to free memory as soon as
possible when left memory is few.
A very simple way can solve this problem:
a field(struct rcu_head::batch) is added to record the batch number for
the RCU callback. And when a new RCU callback is being queued, we
determine the batch number for this callback(head->batch = rcp->cur+1)
and we move this callback to rdp->donelist if we find
that head->batch <= rcp->completed when we process callbacks.
This simple way reduces the wait time for invocation a lot. (about
2.5Grace Period -> 1.5Grace Period in average in multi-CPU systems)
This is my algorithm. But I do not add any field for struct rcu_head
in my implement. We just need to memorize the last 2 batches and
their batch number, because these 2 batches include all entries that
for whom the grace period hasn't completed. So we use a special
linked-list rather than add a field.
Please see the comment of struct rcu_data.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Gautham Shenoy <ego@in.ibm.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
use a batch number(rcp->pending) instead of a flag(rcp->next_pending)
rcu_start_batch() need to change this flag, so mb()s is needed
for memory-access safe.
but(after this patch applied) rcu_start_batch() do not change
this batch number(rcp->pending), rcp->pending is managed by
__rcu_process_callbacks only, and troublesome mb()s are eliminated.
And codes look simpler and clearer.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Gautham Shenoy <ego@in.ibm.com>
Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Real-time code needs to know the number of cycles per second
on SGI UV. The information is provided via a run time BIOS
call. This patch provides the linux side of that interface.
This is the first of several run time BIOS calls to be defined
in uv/bios.h and bios_uv.c.
Note that BIOS_CALL() is just a stub for now. The bios
side is being worked on.
Signed-off-by: Russ Anderson <rja@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Ricardo M. Correia spotted that the use of __fls() in fls64() did
not seem to make sense. In fact fls64()'s implementation is fine,
but the description of __fls() was wrong. Fix that.
Reported-by: "Ricardo M. Correia" <Ricardo.M.Correia@Sun.COM>
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
[ mingo@elte.hu: picked up this patch from Maciej, lets make apic=debug
print out more info - we had a lot of APIC changes ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
