On Fri 26-06-15 11:39:08, sh.yoon@xxxxxxx wrote:
> From: "sh.yoon" <sh.yoon@xxxxxxx>
>
> When zone watermark is not ok in get_page_from_freelist(), we call
> zone_reclaim(). But !CONFIG_NUMA system`s zone_reclaim() just returns zero.
> Zero means ZONE_RECLAIM_SOME and check zone watermark again needlessly.
The return value might be indeed confusing, but
> To avoid needless zone watermark check, change it as ZONE_RECLAIM_NOSCAN.
this shouldn't happen because zone_reclaim_mode is always 0 for
!CONFIG_NUMA so we do not even get to call zone_reclaim. So this part of
the changelog is misleading.
> Signed-off-by: sh.yoon <sh.yoon@xxxxxxx>
> ---
> include/linux/swap.h | 7 ++++++-
> mm/internal.h | 5 -----
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/swap.h b/include/linux/swap.h
> index 3887472..e04e435 100644
> --- a/include/linux/swap.h
> +++ b/include/linux/swap.h
> @@ -332,6 +332,11 @@ extern int vm_swappiness;
> extern int remove_mapping(struct address_space *mapping, struct page *page);
> extern unsigned long vm_total_pages;
>
> +#define ZONE_RECLAIM_NOSCAN -2
> +#define ZONE_RECLAIM_FULL -1
> +#define ZONE_RECLAIM_SOME 0
> +#define ZONE_RECLAIM_SUCCESS 1
> +
> #ifdef CONFIG_NUMA
> extern int zone_reclaim_mode;
> extern int sysctl_min_unmapped_ratio;
> @@ -341,7 +346,7 @@ extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
> #define zone_reclaim_mode 0
> static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
> {
> - return 0;
> + return ZONE_RECLAIM_NOSCAN;
> }
> #endif
>
> diff --git a/mm/internal.h b/mm/internal.h
> index a25e359..d8ec7f8 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -397,11 +397,6 @@ static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
> }
> #endif /* CONFIG_SPARSEMEM */
>
> -#define ZONE_RECLAIM_NOSCAN -2
> -#define ZONE_RECLAIM_FULL -1
> -#define ZONE_RECLAIM_SOME 0
> -#define ZONE_RECLAIM_SUCCESS 1
> -
> extern int hwpoison_filter(struct page *p);
>
> extern u32 hwpoison_filter_dev_major;
> --
> 2.1.4
>
> --
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--
Michal Hocko
SUSE Labs
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