Re: [PATCH] vmscan: ZVC updates in shrink_active_list() can be done once

[Minchan Kim <barrioskmc@gmail.com>]

Reviewed-by: Minchan Kim <minchan.kim@gmail.com>

This fine-grained ZVC update in shrink_active_list was made for
determination problem of the dirty
ratio(c878538598d1e7ab41ecc0de8894e34e2fdef630).
The 32 page reclaim time in normal reclaim situation is too short to
change current VM behavior.
So I think this make sense to me.

On Tue, May 5, 2009 at 8:44 AM, Wu Fengguang <fengguang.wu@intel.com> wrote:
> This effectively lifts the unit of nr_inactive_* and pgdeactivate updates
> from PAGEVEC_SIZE=14 to SWAP_CLUSTER_MAX=32.
>
> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> ---
>  mm/vmscan.c |   11 +++--------
>  1 file changed, 3 insertions(+), 8 deletions(-)
>
> --- linux.orig/mm/vmscan.c
> +++ linux/mm/vmscan.c
> @@ -1228,7 +1228,6 @@ static void shrink_active_list(unsigned
>                        struct scan_control *sc, int priority, int file)
>  {
>        unsigned long pgmoved;
> -       int pgdeactivate = 0;
>        unsigned long pgscanned;
>        LIST_HEAD(l_hold);      /* The pages which were snipped off */
>        LIST_HEAD(l_inactive);
> @@ -1257,7 +1256,7 @@ static void shrink_active_list(unsigned
>                __mod_zone_page_state(zone, NR_ACTIVE_ANON, -pgmoved);
>        spin_unlock_irq(&zone->lru_lock);
>
> -       pgmoved = 0;
> +       pgmoved = 0;  /* count referenced (mapping) mapped pages */
>        while (!list_empty(&l_hold)) {
>                cond_resched();
>                page = lru_to_page(&l_hold);
> @@ -1291,7 +1290,7 @@ static void shrink_active_list(unsigned
>         */
>        reclaim_stat->recent_rotated[!!file] += pgmoved;
>
> -       pgmoved = 0;
> +       pgmoved = 0;  /* count pages moved to inactive list */
>        while (!list_empty(&l_inactive)) {
>                page = lru_to_page(&l_inactive);
>                prefetchw_prev_lru_page(page, &l_inactive, flags);
> @@ -1304,10 +1303,7 @@ static void shrink_active_list(unsigned
>                mem_cgroup_add_lru_list(page, lru);
>                pgmoved++;
>                if (!pagevec_add(&pvec, page)) {
> -                       __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
>                        spin_unlock_irq(&zone->lru_lock);
> -                       pgdeactivate += pgmoved;
> -                       pgmoved = 0;
>                        if (buffer_heads_over_limit)
>                                pagevec_strip(&pvec);
>                        __pagevec_release(&pvec);
> @@ -1315,9 +1311,8 @@ static void shrink_active_list(unsigned
>                }
>        }
>        __mod_zone_page_state(zone, NR_LRU_BASE + lru, pgmoved);
> -       pgdeactivate += pgmoved;
>        __count_zone_vm_events(PGREFILL, zone, pgscanned);
> -       __count_vm_events(PGDEACTIVATE, pgdeactivate);
> +       __count_vm_events(PGDEACTIVATE, pgmoved);
>        spin_unlock_irq(&zone->lru_lock);
>        if (buffer_heads_over_limit)
>                pagevec_strip(&pvec);
>
> --
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-- 
Thanks,
Minchan Kim

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