"Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> writes:
> From: Jagdish Gediya <jvgediya@xxxxxxxxxxxxx>
[...]
> -static struct page *alloc_demote_page(struct page *page, unsigned long node)
> +static struct page *alloc_demote_page(struct page *page, unsigned long private)
> {
> - struct migration_target_control mtc = {
> - /*
> - * Allocate from 'node', or fail quickly and quietly.
> - * When this happens, 'page' will likely just be discarded
> - * instead of migrated.
> - */
> - .gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) |
> - __GFP_THISNODE | __GFP_NOWARN |
> - __GFP_NOMEMALLOC | GFP_NOWAIT,
> - .nid = node
> - };
> + struct page *target_page;
> + nodemask_t *allowed_mask;
> + struct migration_target_control *mtc;
> +
> + mtc = (struct migration_target_control *)private;
> +
> + allowed_mask = mtc->nmask;
> + /*
> + * make sure we allocate from the target node first also trying to
> + * reclaim pages from the target node via kswapd if we are low on
> + * free memory on target node. If we don't do this and if we have low
> + * free memory on the target memtier, we would start allocating pages
> + * from higher memory tiers without even forcing a demotion of cold
> + * pages from the target memtier. This can result in the kernel placing
> + * hotpages in higher memory tiers.
> + */
> + mtc->nmask = NULL;
> + mtc->gfp_mask |= __GFP_THISNODE;
> + target_page = alloc_migration_target(page, (unsigned long)&mtc);
I finally managed to get a system setup to start testing some of this
out. However it quickly crashed due to the bad pointer in the above call
- you need mtc not &mtc here.
> + if (target_page)
> + return target_page;
> +
> + mtc->gfp_mask &= ~__GFP_THISNODE;
> + mtc->nmask = allowed_mask;
>
> return alloc_migration_target(page, (unsigned long)&mtc);
And here.
> }
> @@ -1487,6 +1500,19 @@ static unsigned int demote_page_list(struct list_head *demote_pages,
> {
> int target_nid = next_demotion_node(pgdat->node_id);
> unsigned int nr_succeeded;
> + nodemask_t allowed_mask;
> +
> + struct migration_target_control mtc = {
> + /*
> + * Allocate from 'node', or fail quickly and quietly.
> + * When this happens, 'page' will likely just be discarded
> + * instead of migrated.
> + */
> + .gfp_mask = (GFP_HIGHUSER_MOVABLE & ~__GFP_RECLAIM) | __GFP_NOWARN |
> + __GFP_NOMEMALLOC | GFP_NOWAIT,
> + .nid = target_nid,
> + .nmask = &allowed_mask
> + };
>
> if (list_empty(demote_pages))
> return 0;
> @@ -1494,10 +1520,12 @@ static unsigned int demote_page_list(struct list_head *demote_pages,
> if (target_nid == NUMA_NO_NODE)
> return 0;
>
> + node_get_allowed_targets(pgdat, &allowed_mask);
> +
> /* Demotion ignores all cpuset and mempolicy settings */
> migrate_pages(demote_pages, alloc_demote_page, NULL,
> - target_nid, MIGRATE_ASYNC, MR_DEMOTION,
> - &nr_succeeded);
> + (unsigned long)&mtc, MIGRATE_ASYNC, MR_DEMOTION,
> + &nr_succeeded);
>
> if (current_is_kswapd())
> __count_vm_events(PGDEMOTE_KSWAPD, nr_succeeded);
