linux-kernel - Re: [RFC][PATCH v1 03/11] mm: move definition of num_poisoned_pages

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Date:   Tue, 13 Nov 2018 00:17:31 +0000
From:   Naoya Horiguchi <n-horiguchi@...jp.nec.com>
To:     Anshuman Khandual <anshuman.khandual@....com>
CC:     "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Michal Hocko <mhocko@...nel.org>,
        "Andrew Morton" <akpm@...ux-foundation.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        "xishi.qiuxishi@...baba-inc.com" <xishi.qiuxishi@...baba-inc.com>,
        "Laurent Dufour" <ldufour@...ux.vnet.ibm.com>
Subject: Re: [RFC][PATCH v1 03/11] mm: move definition of
 num_poisoned_pages_inc/dec to include/linux/mm.h

On Fri, Nov 09, 2018 at 03:58:27PM +0530, Anshuman Khandual wrote:
> 
> 
> On 11/09/2018 12:17 PM, Naoya Horiguchi wrote:
> > num_poisoned_pages_inc/dec had better be visible to some file like
> > mm/sparse.c and mm/page_alloc.c (for a subsequent patch). So let's
> > move it to include/linux/mm.h.
> > 
> > Signed-off-by: Naoya Horiguchi <n-horiguchi@...jp.nec.com>
> > ---
> >  include/linux/mm.h      | 13 ++++++++++++-
> >  include/linux/swapops.h | 16 ----------------
> >  mm/sparse.c             |  2 +-
> >  3 files changed, 13 insertions(+), 18 deletions(-)
> > 
> > diff --git v4.19-mmotm-2018-10-30-16-08/include/linux/mm.h v4.19-mmotm-2018-10-30-16-08_patched/include/linux/mm.h
> > index 59df394..22623ba 100644
> > --- v4.19-mmotm-2018-10-30-16-08/include/linux/mm.h
> > +++ v4.19-mmotm-2018-10-30-16-08_patched/include/linux/mm.h
> > @@ -2741,7 +2741,7 @@ extern void shake_page(struct page *p, int access);
> >  extern atomic_long_t num_poisoned_pages __read_mostly;
> >  extern int soft_offline_page(struct page *page, int flags);
> >  
> > -
> > +#ifdef CONFIG_MEMORY_FAILURE
> >  /*
> >   * Error handlers for various types of pages.
> >   */
> > @@ -2777,6 +2777,17 @@ enum mf_action_page_type {
> >  	MF_MSG_UNKNOWN,
> >  };
> >  
> > +static inline void num_poisoned_pages_inc(void)
> > +{
> > +	atomic_long_inc(&num_poisoned_pages);
> > +}
> > +
> > +static inline void num_poisoned_pages_dec(void)
> > +{
> > +	atomic_long_dec(&num_poisoned_pages);
> > +}
> > +#endif
> > +
> >  #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
> >  extern void clear_huge_page(struct page *page,
> >  			    unsigned long addr_hint,
> > diff --git v4.19-mmotm-2018-10-30-16-08/include/linux/swapops.h v4.19-mmotm-2018-10-30-16-08_patched/include/linux/swapops.h
> > index 4d96166..88137e9 100644
> > --- v4.19-mmotm-2018-10-30-16-08/include/linux/swapops.h
> > +++ v4.19-mmotm-2018-10-30-16-08_patched/include/linux/swapops.h
> > @@ -320,8 +320,6 @@ static inline int is_pmd_migration_entry(pmd_t pmd)
> >  
> >  #ifdef CONFIG_MEMORY_FAILURE
> >  
> > -extern atomic_long_t num_poisoned_pages __read_mostly;
> > -
> >  /*
> >   * Support for hardware poisoned pages
> >   */
> > @@ -336,16 +334,6 @@ static inline int is_hwpoison_entry(swp_entry_t entry)
> >  	return swp_type(entry) == SWP_HWPOISON;
> >  }
> >  
> > -static inline void num_poisoned_pages_inc(void)
> > -{
> > -	atomic_long_inc(&num_poisoned_pages);
> > -}
> > -
> > -static inline void num_poisoned_pages_dec(void)
> > -{
> > -	atomic_long_dec(&num_poisoned_pages);
> > -}
> > -
> >  #else
> >  
> >  static inline swp_entry_t make_hwpoison_entry(struct page *page)
> > @@ -357,10 +345,6 @@ static inline int is_hwpoison_entry(swp_entry_t swp)
> >  {
> >  	return 0;
> >  }
> > -
> > -static inline void num_poisoned_pages_inc(void)
> > -{
> > -}
> 
> I hope this was a stray definition and redundant which does not prevent
> build in absence of CONFIG_MEMORY_FAILURE.

You're right :)

> >  #endif
> >  
> >  #if defined(CONFIG_MEMORY_FAILURE) || defined(CONFIG_MIGRATION)
> > diff --git v4.19-mmotm-2018-10-30-16-08/mm/sparse.c v4.19-mmotm-2018-10-30-16-08_patched/mm/sparse.c
> > index 33307fc..7ada2e5 100644
> > --- v4.19-mmotm-2018-10-30-16-08/mm/sparse.c
> > +++ v4.19-mmotm-2018-10-30-16-08_patched/mm/sparse.c
> > @@ -726,7 +726,7 @@ static void clear_hwpoisoned_pages(struct page *memmap, int nr_pages)
> >  
> >  	for (i = 0; i < nr_pages; i++) {
> >  		if (PageHWPoison(&memmap[i])) {
> > -			atomic_long_sub(1, &num_poisoned_pages);
> > +			num_poisoned_pages_dec();
> >  			ClearPageHWPoison(&memmap[i]);
> >  		}
> >  	}
> > 
> 
> Otherwise looks good.
> 
> Reviewed-by: Anshuman Khandual <anshuman.khandual@....com>

Thanks!
Naoya Horiguchi