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From: SeongJae Park <sj@kernel.org>
To: Barry Song <21cnbao@gmail.com>
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Subject: Re: [PATCH v2 5/5] mm: add per-order mTHP swpin_refault counter
Date: Thu, 11 Apr 2024 09:14:25 -0700
Message-Id: <20240411161425.77677-1-sj@kernel.org>
In-Reply-To: <20240411014636.14023-1-21cnbao@gmail.com>
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Hi Barry,

On Thu, 11 Apr 2024 13:46:36 +1200 Barry Song <21cnbao@gmail.com> wrote:

> >> +		count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_SWPIN_REFAULT);
> >>  	}
> >> 
> > From the latest mm-unstable tree, I get below kunit build failure and
> > 'git bisect' points this patch.
> > 
> >     $ ./tools/testing/kunit/kunit.py run --build_dir ../kunit.out/
> >     [16:07:40] Configuring KUnit Kernel ...
> >     [16:07:40] 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:.../mm/memory.c: In function ‘do_swap_page’:
> >     .../mm/memory.c:4169:17: error: implicit declaration of function ‘count_mthp_stat’ [-Werror=implicit-function-declaration]
> >      4169 |                 count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_SWPIN_REFAULT);
> >           |                 ^~~~~~~~~~~~~~~
> >     .../mm/memory.c:4169:53: error: ‘MTHP_STAT_ANON_SWPIN_REFAULT’ undeclared (first use in this function)
> >      4169 |                 count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_SWPIN_REFAULT);
> >           |                                                     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >     .../mm/memory.c:4169:53: note: each undeclared identifier is reported only once for each function it appears in
> >     cc1: some warnings being treated as errors
> > 
> > My kunit build config doesn't have CONFIG_TRANSPARE_HUGEPAGE.  Maybe that's the
> > reason and this patch, or the patch that introduced the function and the enum
> > need to take care of the case?
> 
> Hi SeongJae,
> Thanks very much, can you check if the below fix the build? If yes, I will
> include this fix while sending v3.

Thank you for quick and kind reply :) I confirmed this fixes the build failure.

> 
> Subject: [PATCH] mm: fix build errors on CONFIG_TRANSPARENT_HUGEPAGE=N
> 
> Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Tested-by: SeongJae Park <sj@kernel.org>


Thanks,
SJ

> ---
>  mm/memory.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/memory.c b/mm/memory.c
> index acc023795a4d..1d587d1eb432 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -4142,6 +4142,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
>  	vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address,
>  			&vmf->ptl);
>  
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  	/* We hit large folios in swapcache */
>  	if (start_pte && folio_test_large(folio) && folio_test_swapcache(folio)) {
>  		int nr = folio_nr_pages(folio);
> @@ -4171,6 +4172,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
>  	}
>  
>  check_pte:
> +#endif
>  	if (unlikely(!vmf->pte || !pte_same(ptep_get(vmf->pte), vmf->orig_pte)))
>  		goto out_nomap;
>  
> -- 
> 2.34.1
> 
>