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From: Eric Paris <eparis@redhat.com>
To: Andreas Schwab <schwab@linux-m68k.org>
Cc: Tvrtko Ursulin <tvrtko.ursulin@sophos.com>,
	Andreas Gruenbacher <agruen@suse.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: struct fanotify_event_metadata
Date: Fri, 20 Aug 2010 09:13:36 -0400	[thread overview]
Message-ID: <1282310016.21419.2161.camel@acb20005.ipt.aol.com> (raw)
In-Reply-To: <m3pqxd7ift.fsf@hase.home>

On Fri, 2010-08-20 at 11:16 +0200, Andreas Schwab wrote:
> Tvrtko Ursulin <tvrtko.ursulin@sophos.com> writes:
> 
> > Shrink pid field in the fanotify_event_metadata to 32-bit to match
> > the kernel representation. Pull mask field up since it logically
> > comes before event auxiliary data and also makes for a nicer
> > alignment.
> 
> That won't buy you much wrt. alignment though, due to the packed
> attribute.

Can you help me understand the packed attribute and why it hurts in this
case?  It's not going to change the alignment or placement of anything
and I saw it as just being needed to make sure everything would continue
to work in the future.

I'm going to compile a couple of test programs (I only have x86 and
x86_64) to see if I can find what the assembly is doing different but
maybe you can point me at the information more easily?

-Eric



  parent reply	other threads:[~2010-08-20 13:13 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-14 17:44 Andreas Schwab
2010-08-19 15:44 ` Tvrtko Ursulin
2010-08-19 16:07   ` Andreas Gruenbacher
2010-08-19 16:35     ` Tvrtko Ursulin
2010-08-19 17:53   ` Eric Paris
2010-08-20  9:02     ` Tvrtko Ursulin
2010-08-20  9:16       ` Andreas Schwab
2010-08-20  9:23         ` Tvrtko Ursulin
2010-08-20 13:13         ` Eric Paris [this message]
2010-08-20 13:27           ` Andreas Schwab
2010-08-20 15:19             ` Eric Paris
2010-08-20 17:47               ` Eric Paris

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