linux-kernel - Re: Change signal mask after vfork/clone system call

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Message-ID: <20101104154543.2a71cff1@lxorguk.ukuu.org.uk>
Date:	Thu, 4 Nov 2010 15:45:43 +0000
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Gregory Giguashvili <Gregory.Giguashvili@...M.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Change signal mask after vfork/clone system call

On Thu, 4 Nov 2010 15:37:05 +0000
Gregory Giguashvili <Gregory.Giguashvili@...M.com> wrote:

> > Fork on pretty much any Unix like system around today does copy-on-write
> >so while not as efficient as vfork should be fine for most purposes.
> Yes, but the problem is that fork simply does not work when a process has huge resident size and vm.overcommit_memory=0 as preferred by Linux distributions we run on. So, processes with large RSS footprint may occasionally fail fork, even if a tiny process is to be started.
> 
> Using vfork always works, but has the signal mask problem. Catch 22?

And is there a reason you can't mask the signals, vfork and unmask them
again after the parent continues ?
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