Re: [PATCH 3/3] reset wmark_min and inactive ratio of zone whenhotplug happens V2

[Mel Gorman]

On Thu, May 21, 2009 at 09:23:37AM +0900, Minchan Kim wrote:
> Changelog since V1 
>  o Add Ack-by of Yasunori Goto
>  o Modify setup_per_zone_wmarks's comment
> 
> This patch solve two problems.
> 
> Whenever memory hotplug sucessfully happens, zone->present_pages
> have to be changed.
> 
> 1) Now memory hotplug calls setup_per_zone_wmark_min only when
> online_pages called, not offline_pages.
> 
> It breaks balance.
> 
> 2) If zone->present_pages is changed, we also have to change
> zone->inactive_ratio. That's because inactive_ratio depends
> on zone->present_pages.
> 
> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>
> Acked-by: Yasunori Goto <y-goto@xxxxxxxxxxxxxx>

Acked-by: Mel Gorman <mel@xxxxxxxxx>

> CC: Rik van Riel <riel@xxxxxxxxxx>
> CC: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> CC: Johannes Weiner <hannes@xxxxxxxxxxx>
> ---
>  mm/memory_hotplug.c |    4 ++++
>  mm/page_alloc.c     |    2 +-
>  2 files changed, 5 insertions(+), 1 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 037291e..e4412a6 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -423,6 +423,7 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
>  	zone->zone_pgdat->node_present_pages += onlined_pages;
>  
>  	setup_per_zone_wmarks();
> +	calculate_zone_inactive_ratio(zone);
>  	if (onlined_pages) {
>  		kswapd_run(zone_to_nid(zone));
>  		node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
> @@ -832,6 +833,9 @@ repeat:
>  	totalram_pages -= offlined_pages;
>  	num_physpages -= offlined_pages;
>  
> +	setup_per_zone_wmarks();
> +	calculate_zone_inactive_ratio(zone);
> +
>  	vm_total_pages = nr_free_pagecache_pages();
>  	writeback_set_ratelimit();
>  
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index f11cfbf..d13f9b5 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -4472,7 +4472,7 @@ static void setup_per_zone_lowmem_reserve(void)
>  
>  /**
>   * setup_per_zone_wmarks - called when min_free_kbytes changes 
> - * or when memory is hot-added
> + * or when memory is hot-{added|removed}
>   *
>   * Ensures that the watermark[min,low,high] values for each zone are set correctly
>   * with respect to min_free_kbytes.
> -- 
> 1.5.4.3
> 

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab
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