From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Subject: mm/memory_hotplug: remove a wrapper for alloc_migration_target() To calculate the correct node to migrate the page for hotplug, we need to check node id of the page. Wrapper for alloc_migration_target() exists for this purpose. However, Vlastimil informs that all migration source pages come from a single node. In this case, we don't need to check the node id for each page and we don't need to re-set the target nodemask for each page by using the wrapper. Set up the migration_target_control once and use it for all pages. Link: http://lkml.kernel.org/r/1594622517-20681-10-git-send-email-iamjoonsoo.kim@xxxxxxx Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Cc: Roman Gushchin <guro@xxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memory_hotplug.c | 46 ++++++++++++++++++++---------------------- 1 file changed, 22 insertions(+), 24 deletions(-) --- a/mm/memory_hotplug.c~mm-memory_hotplug-remove-a-wrapper-for-alloc_migration_target +++ a/mm/memory_hotplug.c @@ -1290,27 +1290,6 @@ found: return 0; } -static struct page *new_node_page(struct page *page, unsigned long private) -{ - nodemask_t nmask = node_states[N_MEMORY]; - struct migration_target_control mtc = { - .nid = page_to_nid(page), - .nmask = &nmask, - .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, - }; - - /* - * try to allocate from a different node but reuse this node if there - * are no other online nodes to be used (e.g. we are offlining a part - * of the only existing node) - */ - node_clear(mtc.nid, nmask); - if (nodes_empty(nmask)) - node_set(mtc.nid, nmask); - - return alloc_migration_target(page, (unsigned long)&mtc); -} - static int do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) { @@ -1370,9 +1349,28 @@ do_migrate_range(unsigned long start_pfn put_page(page); } if (!list_empty(&source)) { - /* Allocate a new page from the nearest neighbor node */ - ret = migrate_pages(&source, new_node_page, NULL, 0, - MIGRATE_SYNC, MR_MEMORY_HOTPLUG); + nodemask_t nmask = node_states[N_MEMORY]; + struct migration_target_control mtc = { + .nmask = &nmask, + .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, + }; + + /* + * We have checked that migration range is on a single zone so + * we can use the nid of the first page to all the others. + */ + mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru)); + + /* + * try to allocate from a different node but reuse this node + * if there are no other online nodes to be used (e.g. we are + * offlining a part of the only existing node) + */ + node_clear(mtc.nid, nmask); + if (nodes_empty(nmask)) + node_set(mtc.nid, nmask); + ret = migrate_pages(&source, alloc_migration_target, NULL, + (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG); if (ret) { list_for_each_entry(page, &source, lru) { pr_warn("migrating pfn %lx failed ret:%d ", _
