linux-kernel - Re: which signal is sent to freeze process?

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Date:	Thu, 19 Jul 2007 12:18:32 +1000
From:	Nigel Cunningham <nigel@...el.suspend2.net>
To:	"Agarwal, Lomesh" <lomesh.agarwal@...el.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: which signal is sent to freeze process?

Hi.

On Thursday 19 July 2007 09:42:02 Agarwal, Lomesh wrote:
> My understanding is that Linux kernel sends a signal to freeze processes
> during suspend2ram operation. Which signal is used to achieve this?
> The problem I am facing is that some of the system calls are failing
> with EINTR errno during suspend operation and I want to install a signal
> handler for freeze signal with SA_RESTART flag. That should make the
> kernel to retry the system calls. Right?

No signal is sent. We tell affected processes that they have a signal pending, 
and capture them in the signal handling code while the suspend to ram is 
occuring. After the suspend to ram is finished, we recalculate whether they 
have a signal pending, and let them continue.

Not being a guru on signal handling itself, I won't try to answer the question 
itself :\.

Regards,

Nigel

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