Commit Graph

19 Commits

Author SHA1 Message Date
Zachary Amsden 3908fd2ed9 [PATCH] softirq: remove BUG_ONs which can incorrectly trigger
It is possible to have tasklets get scheduled before softirqd has had a chance
to spawn on all CPUs.  This is totally harmless; after success during action
CPU_UP_PREPARE, action CPU_ONLINE will be called, which immediately wakes
softirqd on the appropriate CPU to process the already pending tasklets.  So
there is no danger of having a missed wakeup for any tasklets that were
already pending.

In particular, i386 is affected by this during startup, and is visible when
using a very large initrd; during the time it takes for the initrd to be
decompressed, a timer IRQ can come in and schedule RCU callbacks.  It is also
possible that resending of a hardware IRQ via a softirq triggers the same bug.

Because of different timing conditions, this shows up in all emulators and
virtual machines tested, including Xen, VMware, Virtual PC, and Qemu.  It is
also possible to trigger on native hardware with a large enough initrd,
although I don't have a reliable case demonstrating that.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Cc: <caglar@pardus.org.tr>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:43 -08:00
Akinobu Mita 07dccf3344 [PATCH] check return value of cpu_callback
Spawing ksoftirqd, migration, or watchdog, and calling init_timers_cpu()
may fail with small memory.  If it happens in initcalls, kernel NULL
pointer dereference happens later.  This patch makes crash happen
immediately in such cases.  It seems a bit better than getting kernel NULL
pointer dereference later.

Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Akinobu Mita <mita@miraclelinux.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-29 09:18:14 -07:00
Tim Chen 3c829c367a [PATCH] Reducing local_bh_enable/disable overhead in irqtrace
The recent changes from irqtrace feature has added overheads to
local_bh_disable and local_bh_enable that reduces UDP performance across
x86_64 and IA64, even though IA64 does not support the irqtrace feature.
Patch in question is

[PATCH]lockdep: irqtrace subsystem, core
http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=c
ommit;h=de30a2b355ea85350ca2f58f3b9bf4e5bc007986

Prior to this patch, local_bh_disable was a short macro.  Now it is a
function which calls __local_bh_disable with added irq flags save and
restore.  The irq flags save and restore were also added to
local_bh_enable, probably for injecting the trace irqs code.

This overhead is on the generic code path across all architectures.  On a
IA_64 test machine (Itanium-2 1.6 GHz) running a benchmark like netperf's
UDP streaming test, the added overhead results in a drop of 3% in
throughput, as udp_sendmsg calls the local_bh_enable/disable several times.

Other workloads that have heavy usages of local_bh_enable/disable could
also be affected.  The patch ideally should not have affected IA-64
performance as it does not have IRQ tracing support.  A significant portion
of the overhead is in the added irq flags save and restore, which I think
is not needed if IRQ tracing is unused.  A suggested patch is attached
below that recovers the lost performance.  However, the "ifdef"s in the
patch are a bit ugly.

Signed-off-by: Tim Chen <tim.c.chen@intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-31 13:28:42 -07:00
Chandra Seetharaman 8c78f3075d [PATCH] cpu hotplug: replace __devinit* with __cpuinit* for cpu notifications
Few of the callback functions and notifier blocks that are associated with cpu
notifications incorrectly have __devinit and __devinitdata.  They should be
__cpuinit and __cpuinitdata instead.

It makes no functional difference but wastes text area when CONFIG_HOTPLUG is
enabled and CONFIG_HOTPLUG_CPU is not.

This patch fixes all those instances.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-31 13:28:39 -07:00
Adrian Bunk 6bc02d8412 [PATCH] unexport open_softirq
Christoph Hellwig:
open_softirq just enables a softirq.  The softirq array is statically
allocated so to add a new one you would have to patch the kernel.  So
there's no point to keep this export at all as any user would have to
patch the enum in include/linux/interrupt.h anyway.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-14 21:53:53 -07:00
Adrian Bunk 80d6679a62 [PATCH] kernel/softirq.c: EXPORT_UNUSED_SYMBOL
This patch marks an unused export as EXPORT_UNUSED_SYMBOL.

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-10 13:24:18 -07:00
Paul Mackerras 829035fd70 [PATCH] lockdep: irqtrace subsystem, move account_system_vtime() calls into kernel/softirq.c
At the moment, powerpc and s390 have their own versions of do_softirq which
include local_bh_disable() and __local_bh_enable() calls.  They end up
calling __do_softirq (in kernel/softirq.c) which also does
local_bh_disable/enable.

Apparently the two levels of disable/enable trigger a warning from some
validation code that Ingo is working on, and he would like to see the outer
level removed.  But to do that, we have to move the account_system_vtime
calls that are currently in the arch do_softirq() implementations for
powerpc and s390 into the generic __do_softirq() (this is a no-op for other
archs because account_system_vtime is defined to be an empty inline
function on all other archs).  This patch does that.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:10 -07:00
Ingo Molnar de30a2b355 [PATCH] lockdep: irqtrace subsystem, core
Accurate hard-IRQ-flags and softirq-flags state tracing.

This allows us to attach extra functionality to IRQ flags on/off
events (such as trace-on/off).

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-07-03 15:27:03 -07:00
Chandra Seetharaman 054cc8a2d8 [PATCH] cpu hotplug: revert initdata patch submitted for 2.6.17
This patch reverts notifier_block changes made in 2.6.17

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 17:32:41 -07:00
Chandra Seetharaman 9c7b216d23 [PATCH] cpu hotplug: revert init patch submitted for 2.6.17
In 2.6.17, there was a problem with cpu_notifiers and XFS.  I provided a
band-aid solution to solve that problem.  In the process, i undid all the
changes you both were making to ensure that these notifiers were available
only at init time (unless CONFIG_HOTPLUG_CPU is defined).

We deferred the real fix to 2.6.18.  Here is a set of patches that fixes the
XFS problem cleanly and makes the cpu notifiers available only at init time
(unless CONFIG_HOTPLUG_CPU is defined).

If CONFIG_HOTPLUG_CPU is defined then cpu notifiers are available at run
time.

This patch reverts the notifier_call changes made in 2.6.17

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-27 17:32:40 -07:00
Heiko Carstens fc75cdfa5b [PATCH] cpu hotplug: fix CPU_UP_CANCEL handling
If a cpu hotplug callback fails on CPU_UP_PREPARE, all callbacks will be
called with CPU_UP_CANCELED.  A few of these callbacks assume that on
CPU_UP_PREPARE a pointer to task has been stored in a percpu array.  This
assumption is not true if CPU_UP_PREPARE fails and the following calls to
kthread_bind() in CPU_UP_CANCELED will cause an addressing exception
because of passing a NULL pointer.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-25 10:01:22 -07:00
Chandra Seetharaman 83d722f7e1 [PATCH] Remove __devinit and __cpuinit from notifier_call definitions
Few of the notifier_chain_register() callers use __init in the definition
of notifier_call.  It is incorrect as the function definition should be
available after the initializations (they do not unregister them during
initializations).

This patch fixes all such usages to _not_ have the notifier_call __init
section.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-26 08:30:03 -07:00
Chandra Seetharaman 649bbaa484 [PATCH] Remove __devinitdata from notifier block definitions
Few of the notifier_chain_register() callers use __devinitdata in the
definition of notifier_block data structure.  It is incorrect as the
data structure should be available after the initializations (they do
not unregister them during initializations).

This was leading to an oops when notifier_chain_register() call is
invoked for those callback chains after initialization.

This patch fixes all such usages to _not_ have the notifier_block data
structure in the init data section.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-04-26 08:27:50 -07:00
Andrew Morton 78eef01b0f [PATCH] on_each_cpu(): disable local interrupts
When on_each_cpu() runs the callback on other CPUs, it runs with local
interrupts disabled.  So we should run the function with local interrupts
disabled on this CPU, too.

And do the same for UP, so the callback is run in the same environment on both
UP and SMP.  (strictly it should do preempt_disable() too, but I think
local_irq_disable is sufficiently equivalent).

Also uninlines on_each_cpu().  softirq.c was the most appropriate file I could
find, but it doesn't seem to justify creating a new file.

Oh, and fix up that comment over (under?) x86's smp_call_function().  It
drives me nuts.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-22 07:53:59 -08:00
Heiko Carstens a4c4af7c8d [PATCH] cpu hoptlug: avoid usage of smp_processor_id() in preemptible code
Replace smp_processor_id() with any_online_cpu(cpu_online_map) in order to
avoid lots of "BUG: using smp_processor_id() in preemptible [00000001]
code:..." messages in case taking a cpu online fails.

All the traces start at the last notifier_call_chain(...) in kernel/cpu.c.
Since we hold the cpu_control semaphore it shouldn't be any problem to access
cpu_online_map.

The reason why cpu_up failed is simply that the cpu that was supposed to be
taken online wasn't even there.  That is because on s390 we never know when a
new cpu comes and therefore cpu_possible_map consists of only ones and doesn't
reflect reality.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-07 07:53:29 -08:00
Andi Kleen 3f74478b5f [PATCH] x86-64: Some cleanup and optimization to the processor data area.
- Remove unused irqrsp field
- Remove pda->me
- Optimize set_softirq_pending slightly

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-12 10:49:58 -07:00
Andrew Morton c70f5d6610 [PATCH] revert bogus softirq changes
This snuck in with an x86_64 change.  Thanks to Richard Purdie
<rpurdie@rpsys.net> for spotting it.

Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-30 10:49:59 -07:00
Andi Kleen ed6b676ca8 [PATCH] x86_64: Switch to the interrupt stack when running a softirq in local_bh_enable()
This avoids some potential stack overflows with very deep softirq callchains.
i386 does this too.

TOADD CFI annotation

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-07-28 21:46:02 -07:00
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00