RE: [PATCH v3 4/4] mm: swap: Count successful mTHP ZSWAP stores in sysfs mTHP stats.

["Sridhar, Kanchana P" <kanchana.p.sridhar@intel.com>]

Hi Barry,

> -----Original Message-----
> From: Barry Song <21cnbao@gmail.com>
> Sent: Sunday, August 18, 2024 12:46 AM
> To: lkp <lkp@intel.com>
> Cc: Sridhar, Kanchana P <kanchana.p.sridhar@intel.com>; linux-
> kernel@vger.kernel.org; linux-mm@kvack.org; hannes@cmpxchg.org;
> yosryahmed@google.com; nphamcs@gmail.com; ryan.roberts@arm.com;
> Huang, Ying <ying.huang@intel.com>; akpm@linux-foundation.org; oe-kbuild-
> all@lists.linux.dev; Zou, Nanhai <nanhai.zou@intel.com>; Feghali, Wajdi K
> <wajdi.k.feghali@intel.com>; Gopal, Vinodh <vinodh.gopal@intel.com>
> Subject: Re: [PATCH v3 4/4] mm: swap: Count successful mTHP ZSWAP stores
> in sysfs mTHP stats.
> 
> On Sun, Aug 18, 2024 at 12:04 PM kernel test robot <lkp@intel.com> wrote:
> >
> > Hi Kanchana,
> >
> > kernel test robot noticed the following build errors:
> >
> > [auto build test ERROR on 7c626ce4bae1ac14f60076d00eafe71af30450ba]
> >
> > url:    https://github.com/intel-lab-lkp/linux/commits/Kanchana-P-
> Sridhar/mm-zswap-zswap_is_folio_same_filled-takes-an-index-in-the-
> folio/20240817-131053
> > base:   7c626ce4bae1ac14f60076d00eafe71af30450ba
> > patch link:    https://lore.kernel.org/r/20240817050921.18462-5-
> kanchana.p.sridhar%40intel.com
> > patch subject: [PATCH v3 4/4] mm: swap: Count successful mTHP ZSWAP
> stores in sysfs mTHP stats.
> > config: x86_64-defconfig (https://download.01.org/0day-
> ci/archive/20240818/202408180729.M6uZh634-lkp@intel.com/config)
> > compiler: gcc-11 (Debian 11.3.0-12) 11.3.0
> > reproduce (this is a W=1 build): (https://download.01.org/0day-
> ci/archive/20240818/202408180729.M6uZh634-lkp@intel.com/reproduce)
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202408180729.M6uZh634-
> lkp@intel.com/
> >
> > All errors (new ones prefixed by >>):
> >
> >    mm/page_io.c: In function 'count_mthp_zswpout_vm_event':
> > >> mm/page_io.c:178:17: error: implicit declaration of function
> 'count_mthp_stat' [-Werror=implicit-function-declaration]
> >      178 |                 count_mthp_stat(folio_order(folio),
> MTHP_STAT_ZSWPOUT);
> >          |                 ^~~~~~~~~~~~~~~
> > >> mm/page_io.c:178:53: error: 'MTHP_STAT_ZSWPOUT' undeclared (first
> use in this function)
> >      178 |                 count_mthp_stat(folio_order(folio),
> MTHP_STAT_ZSWPOUT);
> >          |                                                     ^~~~~~~~~~~~~~~~~
> >    mm/page_io.c:178:53: note: each undeclared identifier is reported only
> once for each function it appears in
> >    cc1: some warnings being treated as errors
> 
> i believe this has been fixed by Ryan's latest cleanup
> https://lore.kernel.org/all/20240808111849.651867-2-
> ryan.roberts@arm.com/
> 
> Kanchana, is your code on top of mm-unstable?

Thanks very much for the pointer to Ryan's latest count_mthp_stat() cleanup patch!
I will submit my patches rebased to mm-unstable, and with changes aligned to
Ryan's patch. Hopefully this should resolve the kernel robot build errors. I believe
this was happening because in v3, I had made the call to count_mthp_stat() conditional
on ifdef CONFIG_THP_SWAP, whereas "enum mthp_stat_item" was defined based
on ifdef CONFIG_TRANSPARENT_HUGEPAGE (in v3).

Please do review the v4 and let me know if this looks good. Thanks again.

Thanks,
Kanchana

> 
> >
> >
> > vim +/count_mthp_stat +178 mm/page_io.c
> >
> >    174
> >    175  static inline void count_mthp_zswpout_vm_event(struct folio *folio)
> >    176  {
> >    177          if (IS_ENABLED(CONFIG_THP_SWAP))
> >  > 178                  count_mthp_stat(folio_order(folio),
> MTHP_STAT_ZSWPOUT);
> >    179  }
> >    180
> >
> > --
> > 0-DAY CI Kernel Test Service
> > https://github.com/intel/lkp-tests/wiki