Re: [External] Re: [PATCH v9 1/2] memory tier: dax/kmem: introduce an abstract layer for finding, allocating, and putting memory types

[Ho-Ren (Jack) Chuang]

Hi SeongJae,

On Sun, Mar 31, 2024 at 12:09 PM SeongJae Park <sj@kernel.org> wrote:
>
> Hi Ho-Ren,
>
> On Fri, 29 Mar 2024 05:33:52 +0000 "Ho-Ren (Jack) Chuang" 
> <horenchuang@bytedance.com> wrote:
>
> > Since different memory devices require finding, allocating, and putting
> > memory types, these common steps are abstracted in this patch,
> > enhancing the scalability and conciseness of the code.
> >
> > Signed-off-by: Ho-Ren (Jack) Chuang <horenchuang@bytedance.com>
> > Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
> > ---
> >  drivers/dax/kmem.c           | 20 ++------------------
> >  include/linux/memory-tiers.h | 13 +++++++++++++
> >  mm/memory-tiers.c            | 32 ++++++++++++++++++++++++++++++++
> >  3 files changed, 47 insertions(+), 18 deletions(-)
> >
> [...]
> > diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
> > index 69e781900082..a44c03c2ba3a 100644
> > --- a/include/linux/memory-tiers.h
> > +++ b/include/linux/memory-tiers.h
> > @@ -48,6 +48,9 @@ int mt_calc_adistance(int node, int *adist);
> >  int mt_set_default_dram_perf(int nid, struct access_coordinate *perf,
> >                            const char *source);
> >  int mt_perf_to_adistance(struct access_coordinate *perf, int *adist);
> > +struct memory_dev_type *mt_find_alloc_memory_type(int adist,
> > +                                                     struct list_head 
> > *memory_types);
> > +void mt_put_memory_types(struct list_head *memory_types);
> >  #ifdef CONFIG_MIGRATION
> >  int next_demotion_node(int node);
> >  void node_get_allowed_targets(pg_data_t *pgdat, nodemask_t *targets);
> > @@ -136,5 +139,15 @@ static inline int mt_perf_to_adistance(struct 
> > access_coordinate *perf, int *adis
> >  {
> >       return -EIO;
> >  }
> > +
> > +struct memory_dev_type *mt_find_alloc_memory_type(int adist, struct 
> > list_head *memory_types)
> > +{
> > +     return NULL;
> > +}
> > +
> > +void mt_put_memory_types(struct list_head *memory_types)
> > +{
> > +
> > +}
>
> I found latest mm-unstable tree is failing kunit as below, and 'git bisect'
> says it happens from this patch.
>
>     $ ./tools/testing/kunit/kunit.py run --build_dir ../kunit.out/
>     [11:56:40] Configuring KUnit Kernel ...
>     [11:56:40] Building KUnit Kernel ...
>     Populating config with:
>     $ make ARCH=um O=../kunit.out/ olddefconfig
>     Building with:
>     $ make ARCH=um O=../kunit.out/ --jobs=36
>     ERROR:root:In file included from .../mm/memory.c:71:
>     .../include/linux/memory-tiers.h:143:25: warning: no previous prototype 
> for ‘mt_find_alloc_memory_type’ [-Wmissing-prototypes]
>       143 | struct memory_dev_type *mt_find_alloc_memory_type(int adist, 
> struct list_head *memory_types)
>           |                         ^~~~~~~~~~~~~~~~~~~~~~~~~
>     .../include/linux/memory-tiers.h:148:6: warning: no previous prototype 
> for ‘mt_put_memory_types’ [-Wmissing-prototypes]
>       148 | void mt_put_memory_types(struct list_head *memory_types)
>           |      ^~~~~~~~~~~~~~~~~~~
>     [...]
>
> Maybe we should set these as 'static inline', like below?  I confirmed this
> fixes the kunit error.  May I ask your opinion?
>

Thanks for catching this. I'm trying to figure out this problem. Will get back.

>
> diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
> index a44c03c2ba3a..ee6e53144156 100644
> --- a/include/linux/memory-tiers.h
> +++ b/include/linux/memory-tiers.h
> @@ -140,12 +140,12 @@ static inline int mt_perf_to_adistance(struct 
> access_coordinate *perf, int *adis
>         return -EIO;
>  }
>
> -struct memory_dev_type *mt_find_alloc_memory_type(int adist, struct 
> list_head *memory_types)
> +static inline struct memory_dev_type *mt_find_alloc_memory_type(int adist, 
> struct list_head *memory_types)
>  {
>         return NULL;
>  }
>
> -void mt_put_memory_types(struct list_head *memory_types)
> +static inline void mt_put_memory_types(struct list_head *memory_types)
>  {
>
>  }
>
>
> Thanks,
> SJ



-- 
Best regards,
Ho-Ren (Jack) Chuang
莊賀任