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Subject: Re: [patch 1/5]thp: improve the error code path
From: Shaohua Li <shaohua.li@intel.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, linux-mm <linux-mm@kvack.org>,
        lkml <linux-kernel@vger.kernel.org>
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Date: Thu, 10 Nov 2011 10:33:15 +0800
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On Thu, 2011-11-10 at 10:18 +0800, Andrea Arcangeli wrote:
> Hi Shaohua,
> 
> On Mon, Nov 07, 2011 at 01:17:29PM +0800, Shaohua Li wrote:
> > On Wed, 2011-10-26 at 09:48 +0800, Shaohua Li wrote:
> > > On Tue, 2011-10-25 at 19:44 +0800, Andrea Arcangeli wrote:
> > > > Hello,
> > > > 
> > > > On Tue, Oct 25, 2011 at 10:58:41AM +0800, Shaohua Li wrote:
> > > > > +#ifdef CONFIG_SYSFS
> > > > > +	sysfs_remove_group(hugepage_kobj, &khugepaged_attr_group);
> > > > > +remove_hp_group:
> > > > > +	sysfs_remove_group(hugepage_kobj, &hugepage_attr_group);
> > > > > +delete_obj:
> > > > > +	kobject_put(hugepage_kobj);
> > > > >  out:
> > > > > +#endif
> > > > 
> > > > Adding an ifdef is making the code worse, the whole point of having
> > > > these functions become noops at build time is to avoid having to add
> > > > ifdefs in the callers.
> > > yes, but hugepage_attr_group is defined in CONFIG_SYSFS. And the
> > > functions are inline functions. They really should be a '#define xxx'.
> 
> hugepage_attr_group is defined even if CONFIG_SYSFS is not set and I
> just made a build with CONFIG_SYSFS=n and it builds just fine without
> any change.

> $ grep CONFIG_SYSFS .config
> # CONFIG_SYSFS is not set
> 
> So we can drop 1/5 above.
this isn't the case in the code. And the code uses hugepage_attr_group
is already within CONFIG_SYSFS, so your build success.