OpenVZ Forum


Home » Mailing lists » Devel » [PATCH 0/4] kmem memcg proposed core changes
Re: [PATCH 2/4] Add a __GFP_SLABMEMCG flag [message #46757 is a reply to message #46751] Sat, 09 June 2012 00:56 Go to previous messageGo to previous message
James Bottomley is currently offline  James Bottomley
Messages: 17
Registered: May 2006
Junior Member
On Fri, 2012-06-08 at 14:31 -0500, Christoph Lameter wrote:
> On Fri, 8 Jun 2012, Glauber Costa wrote:
>
> > */
> > #define __GFP_NOTRACK_FALSE_POSITIVE (__GFP_NOTRACK)
> >
> > -#define __GFP_BITS_SHIFT 25 /* Room for N __GFP_FOO bits */
> > +#define __GFP_BITS_SHIFT 26 /* Room for N __GFP_FOO bits */
> > #define __GFP_BITS_MASK ((__force gfp_t)((1 << __GFP_BITS_SHIFT) - 1))
>
> Please make this conditional on CONFIG_MEMCG or so. The bit can be useful
> in particular on 32 bit architectures.

I really don't think that's at all a good idea. It's asking for trouble
when we don't spot we have a flag overlap. It also means that we're
trusting the reuser to know that their use case can never clash with
CONFIG_MEMGC and I can't think of any configuration where this is
possible currently.

I think making the flag define of __GFP_SLABMEMCG conditional might be a
reasonable idea so we get a compile failure if anyone tries to use it
when !CONFIG_MEMCG.

James

Report message to a moderator

[Message index]
 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: [PATCH] allow a task to join a pid namespace
Next Topic: [PATCH] NFS: hard-code init_net for NFS callback transports
Goto Forum:
  

[ Syndicate this forum (XML) ] [ RSS ] [ PDF ]

Current Time: Thu Oct 16 19:22:14 GMT 2025

Total time taken to generate the page: 0.41673 seconds
Powered by FUDforum Powered by Virtuozzo Containers