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References: <20240329053353.309557-2-horenchuang@bytedance.com> <20240331190857.132490-1-sj@kernel.org>
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From: "Ho-Ren (Jack) Chuang" <horenchuang@bytedance.com>
Date: Mon, 1 Apr 2024 11:27:23 -0700
Message-ID: <CAKPbEqo3_zHF98SRoAz4L-CCGpEm8wN1P2RgPLa_q63e1qeGxQ@mail.gmail.com>
Subject: Re: [External] Re: [PATCH v9 1/2] memory tier: dax/kmem: introduce an
 abstract layer for finding, allocating, and putting memory types
To: SeongJae Park <sj@kernel.org>
Cc: "Huang, Ying" <ying.huang@intel.com>, Gregory Price <gourry.memverge@gmail.com>, 
	aneesh.kumar@linux.ibm.com, mhocko@suse.com, tj@kernel.org, 
	john@jagalactic.com, Eishan Mirakhur <emirakhur@micron.com>, 
	Vinicius Tavares Petrucci <vtavarespetr@micron.com>, Ravis OpenSrc <Ravis.OpenSrc@micron.com>, 
	Alistair Popple <apopple@nvidia.com>, Srinivasulu Thanneeru <sthanneeru@micron.com>, 
	Dan Williams <dan.j.williams@intel.com>, Vishal Verma <vishal.l.verma@intel.com>, 
	Dave Jiang <dave.jiang@intel.com>, Andrew Morton <akpm@linux-foundation.org>, nvdimm@lists.linux.dev, 
	linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, 
	"Ho-Ren (Jack) Chuang" <horenc@vt.edu>, "Ho-Ren (Jack) Chuang" <horenchuang@gmail.com>, qemu-devel@nongnu.org
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Hi SeongJae,

On Sun, Mar 31, 2024 at 12:09=E2=80=AFPM SeongJae Park <sj@kernel.org> wrot=
e:
>
> Hi Ho-Ren,
>
> On Fri, 29 Mar 2024 05:33:52 +0000 "Ho-Ren (Jack) Chuang" <horenchuang@by=
tedance.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 acce=
ss_coordinate *perf, int *adis
> >  {
> >       return -EIO;
> >  }
> > +
> > +struct memory_dev_type *mt_find_alloc_memory_type(int adist, struct li=
st_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 bisec=
t'
> 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=3Dum O=3D../kunit.out/ olddefconfig
>     Building with:
>     $ make ARCH=3Dum O=3D../kunit.out/ --jobs=3D36
>     ERROR:root:In file included from .../mm/memory.c:71:
>     .../include/linux/memory-tiers.h:143:25: warning: no previous prototy=
pe for =E2=80=98mt_find_alloc_memory_type=E2=80=99 [-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 prototyp=
e for =E2=80=98mt_put_memory_types=E2=80=99 [-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 th=
is
> fixes the kunit error.  May I ask your opinion?
>

Thanks for catching this. I'm trying to figure out this problem. Will get b=
ack.

>
> 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 acces=
s_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 adis=
t, 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


--=20
Best regards,
Ho-Ren (Jack) Chuang
=E8=8E=8A=E8=B3=80=E4=BB=BB