Messages in this thread | | | Subject | Re: [PATCH v4 11/11] mm/memory_hotplug: remove a wrapper for alloc_migration_target() | From | Vlastimil Babka <> | Date | Tue, 7 Jul 2020 17:09:16 +0200 |
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On 7/7/20 9:44 AM, js1304@gmail.com wrote: > From: Joonsoo Kim <iamjoonsoo.kim@lge.com> > > 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. > > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Thanks! Nitpick below.
> @@ -1345,9 +1324,28 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_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, *mtc.nmask); > + if (nodes_empty(*mtc.nmask)) > + node_set(mtc.nid, *mtc.nmask);
You could have kept using 'nmask' instead of '*mtc.nmask'. Actually that applies to patch 6 too, for less churn.
> + 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 ", >
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