From mboxrd@z Thu Jan  1 00:00:00 1970
From: Roland Dreier <rdreier@cisco.com>
Subject: Re: [RFC][PATCH] reduce KVM stack usage
Date: Thu, 17 Jul 2008 16:02:10 -0700
Message-ID: <adavdz46rnx.fsf@cisco.com>
References: <1216308735.9161.3.camel@nimitz> <aday7408qp3.fsf@cisco.com>
	<1216315391.9311.3.camel@nimitz>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: Avi Kivity <avi@argo.co.il>, kvm-devel <kvm@vger.kernel.org>,
	Anthony Liguori <aliguori@us.ibm.com>
To: Dave Hansen <dave@linux.vnet.ibm.com>
Return-path: <kvm-owner@vger.kernel.org>
Received: from sj-iport-3.cisco.com ([171.71.176.72]:37070 "EHLO
	sj-iport-3.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1751346AbYGQXCM (ORCPT <rfc822;kvm@vger.kernel.org>);
	Thu, 17 Jul 2008 19:02:12 -0400
In-Reply-To: <1216315391.9311.3.camel@nimitz> (Dave Hansen's message of "Thu,
	17 Jul 2008 10:23:11 -0700")
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

 > >  > +		kmalloc(GFP_KERNEL, sizeof(struct kvm_pv_mmu_op_buffer));

 > > Surely this produces a warning?  kmalloc takes (size, flags) -- you have
 > > them reversed here.

 > Heh.  It actually doesn't.  

Yeah, I guess you need sparse to catch the gfp_t mismatch.

 > > kfree(NULL) is fine, so you can remove the if()s here.

 > I know it is fine, but I kinda like putting the if()s, just to let
 > people know that we don't always *expect* something to be in there.
 > But, it doesn't matter to me too much either way.

It's not really a big deal, but "if (x) kfree(x);" does bloat the object
code with the extra test of 'x'.  I guess you could put a comment like
/* free any temp structures we allocated */ or something like that.

 - R.