Re: [PATCH -mmotm v2] mm: fix kmemcheck.c build errors

From: Joonsoo Kim
Date: Sun Aug 31 2014 - 20:29:44 EST


On Sun, Aug 31, 2014 at 05:17:14PM -0700, Randy Dunlap wrote:
> On 08/31/14 17:13, Joonsoo Kim wrote:
> > On Sun, Aug 31, 2014 at 04:33:12PM -0700, Randy Dunlap wrote:
> >> On 08/31/14 07:48, Randy Dunlap wrote:
> >>> On 08/31/14 04:36, Andrey Ryabinin wrote:
> >>>> 2014-08-30 5:48 GMT+04:00 Randy Dunlap <rdunlap@xxxxxxxxxxxxx>:
> >>>>> From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> >>>>>
> >>>>> Add header file to fix kmemcheck.c build errors:
> >>>>>
> >>>>> ../mm/kmemcheck.c:70:7: error: dereferencing pointer to incomplete type
> >>>>> ../mm/kmemcheck.c:83:15: error: dereferencing pointer to incomplete type
> >>>>> ../mm/kmemcheck.c:95:8: error: dereferencing pointer to incomplete type
> >>>>> ../mm/kmemcheck.c:95:21: error: dereferencing pointer to incomplete type
> >>>>>
> >>>>> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> >>>>> ---
> >>>>> mm/kmemcheck.c | 1 +
> >>>>> 1 file changed, 1 insertion(+)
> >>>>>
> >>>>> Index: mmotm-2014-0829-1515/mm/kmemcheck.c
> >>>>> ===================================================================
> >>>>> --- mmotm-2014-0829-1515.orig/mm/kmemcheck.c
> >>>>> +++ mmotm-2014-0829-1515/mm/kmemcheck.c
> >>>>> @@ -2,6 +2,7 @@
> >>>>> #include <linux/mm_types.h>
> >>>>> #include <linux/mm.h>
> >>>>> #include <linux/slab.h>
> >>>>> +#include <linux/slab_def.h>
> >>>>
> >>>> This will work only for CONFIG_SLAB=y. struct kmem_cache definition
> >>>> was moved to internal header [*],
> >>>> so you need to include it here:
> >>>> #include "slab.h"
> >>>>
> >>>> [*] http://ozlabs.org/~akpm/mmotm/broken-out/mm-slab_common-move-kmem_cache-definition-to-internal-header.patch
> >>>
> >>> Thanks. That makes sense. [testing] mm/kmemcheck.c still has a build error:
> >>>
> >>> In file included from ../mm/kmemcheck.c:5:0:
> >>> ../mm/slab.h: In function 'cache_from_obj':
> >>> ../mm/slab.h:283:2: error: implicit declaration of function 'memcg_kmem_enabled' [-Werror=implicit-function-declaration]
> >>>
> >>
> >> Naughty header file. It uses something from <linux/memcontrol.h> without
> >> #including that header file...
> >
> >
> > Hello.
> >
> > Indeed...
> > Thanks for catching this.
> >
> >>
> >> Working patch is below.
> >
> > With your patch, build also failed if CONFIG_MEMCG_KMEM=y.
> > Right fix is something like below.
> >
> > Thanks.
> >
> > --------->8----------
> > diff --git a/mm/kmemcheck.c b/mm/kmemcheck.c
> > index fd814fd..cab58bb 100644
> > --- a/mm/kmemcheck.c
> > +++ b/mm/kmemcheck.c
> > @@ -2,6 +2,7 @@
> > #include <linux/mm_types.h>
> > #include <linux/mm.h>
> > #include <linux/slab.h>
> > +#include "slab.h"
> > #include <linux/kmemcheck.h>
> >
> > void kmemcheck_alloc_shadow(struct page *page, int order, gfp_t flags, int node)
> > diff --git a/mm/slab.h b/mm/slab.h
> > index 13845d0..963a3f8 100644
> > --- a/mm/slab.h
> > +++ b/mm/slab.h
> > @@ -37,6 +37,8 @@ struct kmem_cache {
> > #include <linux/slub_def.h>
> > #endif
> >
> > +#include <linux/memcontrol.h>
> > +
> > /*
> > * State of the slab allocator.
> > *
> > --
>
> Um, yeah, looks equivalent to what I sent as v2.
>

The only difference is that memcg header is slightly move up in mm/slab.h. :)

Thanks.
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