Re: [PATCH v2 1/6] mm/page_alloc: recalculate some of zone threshold when on/offline memory

[Joonsoo Kim]

On Thu, Apr 28, 2016 at 03:46:33PM +0800, Rui Teng wrote:
> On 4/25/16 1:21 PM, js1304@xxxxxxxxx wrote:
> >From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> >
> >Some of zone threshold depends on number of managed pages in the zone.
> >When memory is going on/offline, it can be changed and we need to
> >adjust them.
> >
> >This patch add recalculation to appropriate places and clean-up
> >related function for better maintanance.
> >
> >Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> >---
> > mm/page_alloc.c | 36 +++++++++++++++++++++++++++++-------
> > 1 file changed, 29 insertions(+), 7 deletions(-)
> >
> >diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> >index 71fa015..ffa93e0 100644
> >--- a/mm/page_alloc.c
> >+++ b/mm/page_alloc.c
> >@@ -4633,6 +4633,8 @@ int local_memory_node(int node)
> > }
> > #endif
> >
> >+static void setup_min_unmapped_ratio(struct zone *zone);
> >+static void setup_min_slab_ratio(struct zone *zone);
> > #else	/* CONFIG_NUMA */
> >
> > static void set_zonelist_order(void)
> >@@ -5747,9 +5749,8 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat)
> > 		zone->managed_pages = is_highmem_idx(j) ? realsize : freesize;
> > #ifdef CONFIG_NUMA
> > 		zone->node = nid;
> >-		zone->min_unmapped_pages = (freesize*sysctl_min_unmapped_ratio)
> >-						/ 100;
> >-		zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100;
> >+		setup_min_unmapped_ratio(zone);
> >+		setup_min_slab_ratio(zone);
> 
> The original logic use freesize to calculate the
> zone->min_unmapped_pages and zone->min_slab_pages here.
> But the new function will use zone->managed_pages.
> Do you mean the original logic is wrong, or the managed_pages will
> always be freesize when CONFIG_NUMA defined?

managed_pages will always be freesize so no problem.

Thanks.