RE: which signal is sent to freeze process?

From: Agarwal, Lomesh
Date: Mon Jul 23 2007 - 18:18:38 EST


The net effect would be same. Why would you choose one over other
(do_sys_poll vs. do_poll)?
Can you point me to code where socket read returns in case of
signal_pending? I need to try couple of things.

-----Original Message-----
From: Rafael J. Wysocki [mailto:rjw@xxxxxxx]
Sent: Monday, July 23, 2007 2:51 PM
To: Agarwal, Lomesh
Cc: nigel@xxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: which signal is sent to freeze process?

On Monday, 23 July 2007 22:57, Agarwal, Lomesh wrote:
> Why do you need try_to_freeze in below patch? Shouldn't
> !freezing(current) checking is enough?

The try_to_freeze() is needed so that the process doesn't block the
freezing
of tasks (it is supposed to call refrigerator() as soon as reasonably
possible
when freezing(current) is true).

Alternatively, we might return 0 from do_sys_poll() if do_poll() has
returned 0 and both signal_pending(current) and freezing(current) are
true. Below is a patch that implements that. Could you please try it?

Greetings,
Rafael


---
fs/select.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.22-rc6-mm1/fs/select.c
===================================================================
--- linux-2.6.22-rc6-mm1.orig/fs/select.c
+++ linux-2.6.22-rc6-mm1/fs/select.c
@@ -722,7 +722,7 @@ int do_sys_poll(struct pollfd __user *uf
walk = walk->next;
}
err = fdcount;
- if (!fdcount && signal_pending(current))
+ if (!fdcount && (signal_pending(current) && !freezing(current)))
err = -EINTR;
out_fds:
walk = head;
-
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