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From: Mark Gross <mgross@unix-os.sc.intel.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: alan@lxorguk.ukuu.org.uk (Alan Cox),
	dan@debian.org (Daniel Jacobowitz),
	vamsi@in.ibm.com (Vamsi Krishna S .),
	pavel@suse.cz (Pavel Machek),
	linux-kernel@vger.kernel.org, marcelo@conectiva.com.br,
	tachino@jp.fujitsu.com, jefreyr@pacbell.net,
	vamsi_krishna@in.ibm.com, richardj_moore@uk.ibm.com,
	hanharat@us.ibm.com, bsuparna@in.ibm.com, bharata@in.ibm.com,
	asit.k.mallick@intel.com, david.p.howell@intel.com,
	tony.luck@intel.com, sunil.saxena@intel.com
Subject: Re: [PATCH] multithreaded coredumps for elf exeecutables
Date: Thu, 21 Mar 2002 09:59:49 -0500	[thread overview]
Message-ID: <200203211756.g2LHuvW11535@unix-os.sc.intel.com> (raw)
In-Reply-To: <E16o6SJ-0005mD-00@the-village.bc.nu>

On Thursday 21 March 2002 12:34 pm, Alan Cox wrote:
> > This why I grabbed all those locks, and did the two sets of IPI's in the
> > tcore patch.  Once the runqueue lock is grabbed, even if that process on
> > the
>
> If you IPI holding a lock whats going to happen if while the IPI is going
> across the cpus the other processor tries to grab the runqueue lock and
> is spinning on it with interrupts off ?

Then the at least 2 CPU's would quickly become dead locked on the 
synchronization IPI this patch sends at the end of the suspend_other_threads 
function call.

Interrupts shouldn't be turned off when grabbing the runqueue lock.  Its also 
a bad thing if they would happen to be off while calling into to schedule.  

I think schedule was designed to be called only while interrupts are turned 
on.  It BUG's if "in_interrupt" to enforce this.

--mgross


  reply	other threads:[~2002-03-21 17:57 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-03-15 11:37 Vamsi Krishna S .
2002-03-19 15:29 ` Pavel Machek
2002-03-19 18:49   ` Mark Gross
2002-03-20  6:06     ` Vamsi Krishna S .
2002-03-20 18:37       ` Daniel Jacobowitz
2002-03-20 16:14         ` Mark Gross
2002-03-21 10:03           ` Vamsi Krishna S .
2002-03-22 16:19             ` Mark Gross
2002-03-21 10:16         ` Vamsi Krishna S .
2002-03-21 16:27           ` Daniel Jacobowitz
2002-03-21 16:52             ` Alan Cox
2002-03-21 14:10               ` Mark Gross
2002-03-21 17:34                 ` Alan Cox
2002-03-21 14:59                   ` Mark Gross [this message]
2002-03-21 20:25                 ` Pavel Machek
2002-03-22  6:06 Suparna Bhattacharya
2002-03-29  5:43 ` Jeff Jenkins
2002-03-29 12:50   ` Mark Gross

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