PATCH[2.6.32] softirq patch

PATCH[2.6.32] softirq patch

[Sadasivan Shaiju]

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Hi ,

I  work for Montavista (Cavium Inc) as  a  Technical  Lead .  I want to
push some  of the kernel  patches to  rt community (2.6.32 kernel 2.6.33
rt patch)  , so  that  It  will  go  to  the  main line
These patches  are reviewed  and approved  by  our system Architect.  I
request  you to  include  in the main line .  These  issues  were
reported  by our customer CISCO.

Problem Description:
>From time to time, the following warning appears in the kernel logs on
x86, OCTEON Plus and Octeon II:

NOHZ: local_softirq_pending 08

Root Cause:
In run_ksoftirqd, _local_bh_enable() is used to enable bottom half.
This does not kick off softirq processing.

How Solved:
In run_ksoftirqd, _local_bh_enable() has been replaced with
local_bh_enable() to
enable softirq processing .

Here  I  am attaching  the  patch  for  the  above  bug .   If  any
questions  please  contact  me  at    sshaiju@mvista.com
(shaiju_sada@yahoo.com)

Regards,
Shaiju.

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From 2fa7121b912754f8149774d6a012becf542ffa18 Mon Sep 17 00:00:00 2001
From: Sadasivan Shaiju <sshaiju@mvista.com>
Date: Mon, 6 Feb 2012 18:54:53 -0800
Subject: [PATCH] softirq: Call do_softirq() from run_ksoftirqd() when needed

Source: MontaVista Software, LLC
MR: 47371
Type: Defect Fix
Disposition: Local
ChangeID: 3066b1f971e16b3fc22e6c4e4bba9c6786811acc
Description:

In run_ksoftirqd _local_bh_enable() has to be replaced with
local_bh_enable() to enable softirq processing.

The call to _local_bh_enable() was introduced in the merge of
RT patch-2.6.33-rt7.

Signed-off-by: Sadasivan Shaiju <sshaiju@mvista.com>
Signed-off-by: Dale Farnsworth <dfarnsworth@mvista.com>
---
 kernel/softirq.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 67116c8..cdf52d2 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -1080,7 +1080,7 @@ sleep_more:
 
 			local_irq_disable();
 			per_cpu(softirq_running, cpu) &= ~softirq_mask;
-			_local_bh_enable();
+			local_bh_enable();
 			local_irq_enable();
 
 			cond_resched();
-- 
1.7.0.1

Re: PATCH[2.6.32] softirq patch

[Thomas Gleixner]

On Mon, 11 Aug 2014, Sadasivan Shaiju wrote:
> I  work for Montavista (Cavium Inc) as  a  Technical  Lead .

Weird, IIRC semiconductor companies switched to Lead Free about 8
years ago.

> I want to push some of the kernel patches to rt community (2.6.32
> kernel 2.6.33 rt patch)

See Documentation/SubmittingPatches #9

 "If the patch does not apply cleanly to the latest kernel version,
  Linus will not apply it."

Neither do I. I really give a shit about a Frankenkernel cobbled
together by MVista based on 2.6.32 plus a unknown shitload of crap and
2.6.33-whatever-random-patch-version duct-taped on it.

>  , so  that  It  will  go  to  the  main line

The only way it will go is to /dev/null

> These patches  are reviewed  and approved  by  our system Architect.  I

Congratulations. Print the approval and pin it to your cubicle wall. 

> request  you to  include  in the main line . 

You can request a Pony and you wont get it.

> These issues were reported by our customer CISCO.

Who cares and how is that relevant to the problem at hand?
 
> Problem Description:
> >From time to time, the following warning appears in the kernel logs on
> x86, OCTEON Plus and Octeon II:

Great, so anything else than those three is not affected.
 
> NOHZ: local_softirq_pending 08
> 
> Root Cause:
> In run_ksoftirqd, _local_bh_enable() is used to enable bottom half.
> This does not kick off softirq processing.

That's a real new information, perhaps not ....

See Documentation/SubmittingPatches #2

> How Solved:
> In run_ksoftirqd, _local_bh_enable() has been replaced with
> local_bh_enable() to
> enable softirq processing .

See Documentation/SubmittingPatches #2
 
> Here  I  am attaching  the  patch  for  the  above  bug .   If  any

See Documentation/SubmittingPatches #7

> questions  please  contact  me  at    sshaiju@mvista.com
> (shaiju_sada@yahoo.com)

Aside of failing to submit a proper patch:

If this is MVistas answer to the concerns I raised in the last year,
then please tell those who tasked you to waste your time on providing
completely useless shit to those, who provided the technology on which
that useless shit is based on, that they are on the wrong track.

Thanks,

	tglx

Re: PATCH[2.6.32] softirq patch

[Pavel Vasilyev]

03.09.2014 02:07, Thomas Gleixner пишет:
> On Mon, 11 Aug 2014, Sadasivan Shaiju wrote:

> Aside of failing to submit a proper patch:
>
> If this is MVistas answer to the concerns I raised in the last year,
> then please tell those who tasked you to waste your time on providing
> completely useless shit to those, who provided the technology on which
> that useless shit is based on, that they are on the wrong track.

Kill'em all! :D

-- 

                                                          Pavel.
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RE: PATCH[2.6.32] softirq patch

[Sadasivan Shaiju]

Hi  Thomas,Pavel,

I  will  talk  to  the concerned  people  in  Montavista/cavium   and  make
sure  the  relationship  improves.

I  will  make  a  note  of  the  points  you  have  made.

Regards,
Shaiju.

-----Original Message-----
From: Pavel Vasilyev [mailto:pavel@pavlinux.ru]
Sent: Tuesday, September 02, 2014 3:42 PM
To: Thomas Gleixner; Sadasivan Shaiju
Cc: linux-rt-users@vger.kernel.org; shaiju_sada@yahoo.com
Subject: Re: PATCH[2.6.32] softirq patch

03.09.2014 02:07, Thomas Gleixner пишет:
> On Mon, 11 Aug 2014, Sadasivan Shaiju wrote:

> Aside of failing to submit a proper patch:
>
> If this is MVistas answer to the concerns I raised in the last year,
> then please tell those who tasked you to waste your time on providing
> completely useless shit to those, who provided the technology on which
> that useless shit is based on, that they are on the wrong track.

Kill'em all! :D

-- 

                                                          Pavel.
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