Re: [PATCH] memory-hotplug: use PFN_DOWN in should_add_memory_movable
From: Michal Hocko
Date: Wed Nov 18 2015 - 11:51:41 EST
On Wed 18-11-15 21:31:32, Geliang Tang wrote:
> Use PFN_DOWN() in should_add_memory_movable() to keep the consistency
> of this file.
I really detest this patch and c8e861a531b0 ("mm/memory_hotplug.c: use
PFN_DOWN()") which has started to use PFN_DOWN in that file likewise.
It obfuscates a perfectly understandable construct of addr->pfn
conversion by a macro which I have to really check what it does because
the name suggests I am rounding an existing pfn down.
This really doesn't help the readability.
> Signed-off-by: Geliang Tang <geliangtang@xxxxxxx>
> mm/memory_hotplug.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 67d488a..7c44ff7 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1205,7 +1205,7 @@ static int check_hotplug_memory_range(u64 start, u64 size)
> static int should_add_memory_movable(int nid, u64 start, u64 size)
> - unsigned long start_pfn = start >> PAGE_SHIFT;
> + unsigned long start_pfn = PFN_DOWN(start);
> pg_data_t *pgdat = NODE_DATA(nid);
> struct zone *movable_zone = pgdat->node_zones + ZONE_MOVABLE;
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