[PATCH] mm, memory_hotplug: update pcp lists everytime onlining a memory block

From: Charan Teja Reddy
Date: Sun Aug 02 2020 - 09:01:44 EST

When onlining a first memory block in a zone, pcp lists are not updated
thus pcp struct will have the default setting of ->high = 0,->batch = 1.
This means till the second memory block in a zone(if it have) is onlined
the pcp lists of this zone will not contain any pages because pcp's
->count is always greater than ->high thus free_pcppages_bulk() is
called to free batch size(=1) pages every time system wants to add a
page to the pcp list through free_unref_page(). To put this in a word,
system is not using benefits offered by the pcp lists when there is a
single onlineable memory block in a zone. Correct this by always
updating the pcp lists when memory block is onlined.

Signed-off-by: Charan Teja Reddy <charante@xxxxxxxxxxxxxx>
mm/memory_hotplug.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index dcdf327..7f62d69 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -854,8 +854,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
node_states_set_node(nid, &arg);
if (need_zonelists_rebuild)
- else
- zone_pcp_update(zone);
+ zone_pcp_update(zone);


QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member of the Code Aurora Forum, hosted by The Linux Foundation