On 12/15/18 12:03 AM, Mel Gorman wrote:
> It's non-obvious that high-order free pages are split into order-0
> pages from the function name. Fix it.
That's fine, but looks like the patch has another change squashed into
it that removes zone parameter from several functions and uses cc->zone
instead.
> Signed-off-by: Mel Gorman <mgor...@techsingularity.net>
> ---
> mm/compaction.c | 60
> ++++++++++++++++++++++++++++-----------------------------
> 1 file changed, 29 insertions(+), 31 deletions(-)
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index fb4d9f52ed56..3afa4e9188b6 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -66,7 +66,7 @@ static unsigned long release_freepages(struct list_head
> *freelist)
> return high_pfn;
> }
>
> -static void map_pages(struct list_head *list)
> +static void split_map_pages(struct list_head *list)
> {
> unsigned int i, order, nr_pages;
> struct page *page, *next;
> @@ -644,7 +644,7 @@ isolate_freepages_range(struct compact_control *cc,
> }
>
> /* __isolate_free_page() does not map the pages */
> - map_pages(&freelist);
> + split_map_pages(&freelist);
>
> if (pfn < end_pfn) {
> /* Loop terminated early, cleanup. */
> @@ -1141,7 +1141,7 @@ static void isolate_freepages(struct compact_control
> *cc)
> }
>
> /* __isolate_free_page() does not map the pages */
> - map_pages(freelist);
> + split_map_pages(freelist);
>
> /*
> * Record where the free scanner will restart next time. Either we
> @@ -1300,8 +1300,7 @@ static inline bool is_via_compact_memory(int order)
> return order == -1;
> }
>
> -static enum compact_result __compact_finished(struct zone *zone,
> - struct compact_control *cc)
> +static enum compact_result __compact_finished(struct compact_control *cc)
> {
> unsigned int order;
> const int migratetype = cc->migratetype;
> @@ -1312,7 +1311,7 @@ static enum compact_result __compact_finished(struct
> zone *zone,
> /* Compaction run completes if the migrate and free scanner meet */
> if (compact_scanners_met(cc)) {
> /* Let the next compaction start anew. */
> - reset_cached_positions(zone);
> + reset_cached_positions(cc->zone);
>
> /*
> * Mark that the PG_migrate_skip information should be cleared
> @@ -1321,7 +1320,7 @@ static enum compact_result __compact_finished(struct
> zone *zone,
> * based on an allocation request.
> */
> if (cc->direct_compaction)
> - zone->compact_blockskip_flush = true;
> + cc->zone->compact_blockskip_flush = true;
>
> if (cc->whole_zone)
> return COMPACT_COMPLETE;
> @@ -1345,7 +1344,7 @@ static enum compact_result __compact_finished(struct
> zone *zone,
>
> /* Direct compactor: Is a suitable page free? */
> for (order = cc->order; order < MAX_ORDER; order++) {
> - struct free_area *area = &zone->free_area[order];
> + struct free_area *area = &cc->zone->free_area[order];
> bool can_steal;
>
> /* Job done if page is free of the right migratetype */
> @@ -1391,13 +1390,12 @@ static enum compact_result __compact_finished(struct
> zone *zone,
> return COMPACT_NO_SUITABLE_PAGE;
> }
>
> -static enum compact_result compact_finished(struct zone *zone,
> - struct compact_control *cc)
> +static enum compact_result compact_finished(struct compact_control *cc)
> {
> int ret;
>
> - ret = __compact_finished(zone, cc);
> - trace_mm_compaction_finished(zone, cc->order, ret);
> + ret = __compact_finished(cc);
> + trace_mm_compaction_finished(cc->zone, cc->order, ret);
> if (ret == COMPACT_NO_SUITABLE_PAGE)
> ret = COMPACT_CONTINUE;
>
> @@ -1524,16 +1522,16 @@ bool compaction_zonelist_suitable(struct
> alloc_context *ac, int order,
> return false;
> }
>
> -static enum compact_result compact_zone(struct zone *zone, struct
> compact_control *cc)
> +static enum compact_result compact_zone(struct compact_control *cc)
> {
> enum compact_result ret;
> - unsigned long start_pfn = zone->zone_start_pfn;
> - unsigned long end_pfn = zone_end_pfn(zone);
> + unsigned long start_pfn = cc->zone->zone_start_pfn;
> + unsigned long end_pfn = zone_end_pfn(cc->zone);
> unsigned long last_migrated_pfn;
> const bool sync = cc->mode != MIGRATE_ASYNC;
>
> cc->migratetype = gfpflags_to_migratetype(cc->gfp_mask);
> - ret = compaction_suitable(zone, cc->order, cc->alloc_flags,
> + ret = compaction_suitable(cc->zone, cc->order, cc->alloc_flags,
> cc->classzone_idx);
> /* Compaction is likely to fail */
> if (ret == COMPACT_SUCCESS || ret == COMPACT_SKIPPED)
> @@ -1546,8 +1544,8 @@ static enum compact_result compact_zone(struct zone
> *zone, struct compact_contro
> * Clear pageblock skip if there were failures recently and compaction
> * is about to be retried after being deferred.
> */
> - if (compaction_restarting(zone, cc->order))
> - __reset_isolation_suitable(zone);
> + if (compaction_restarting(cc->zone, cc->order))
> + __reset_isolation_suitable(cc->zone);
>
> /*
> * Setup to move all movable pages to the end of the zone. Used cached
> @@ -1559,16 +1557,16 @@ static enum compact_result compact_zone(struct zone
> *zone, struct compact_contro
> cc->migrate_pfn = start_pfn;
> cc->free_pfn = pageblock_start_pfn(end_pfn - 1);
> } else {
> - cc->migrate_pfn = zone->compact_cached_migrate_pfn[sync];
> - cc->free_pfn = zone->compact_cached_free_pfn;
> + cc->migrate_pfn = cc->zone->compact_cached_migrate_pfn[sync];
> + cc->free_pfn = cc->zone->compact_cached_free_pfn;
> if (cc->free_pfn < start_pfn || cc->free_pfn >= end_pfn) {
> cc->free_pfn = pageblock_start_pfn(end_pfn - 1);
> - zone->compact_cached_free_pfn = cc->free_pfn;
> + cc->zone->compact_cached_free_pfn = cc->free_pfn;
> }
> if (cc->migrate_pfn < start_pfn || cc->migrate_pfn >= end_pfn) {
> cc->migrate_pfn = start_pfn;
> - zone->compact_cached_migrate_pfn[0] = cc->migrate_pfn;
> - zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn;
> + cc->zone->compact_cached_migrate_pfn[0] =
> cc->migrate_pfn;
> + cc->zone->compact_cached_migrate_pfn[1] =
> cc->migrate_pfn;
> }
>
> if (cc->migrate_pfn == start_pfn)
> @@ -1582,11 +1580,11 @@ static enum compact_result compact_zone(struct zone
> *zone, struct compact_contro
>
> migrate_prep_local();
>
> - while ((ret = compact_finished(zone, cc)) == COMPACT_CONTINUE) {
> + while ((ret = compact_finished(cc)) == COMPACT_CONTINUE) {
> int err;
> unsigned long start_pfn = cc->migrate_pfn;
>
> - switch (isolate_migratepages(zone, cc)) {
> + switch (isolate_migratepages(cc->zone, cc)) {
> case ISOLATE_ABORT:
> ret = COMPACT_CONTENDED;
> putback_movable_pages(&cc->migratepages);
> @@ -1653,7 +1651,7 @@ static enum compact_result compact_zone(struct zone
> *zone, struct compact_contro
> if (last_migrated_pfn < current_block_start) {
> cpu = get_cpu();
> lru_add_drain_cpu(cpu);
> - drain_local_pages(zone);
> + drain_local_pages(cc->zone);
> put_cpu();
> /* No more flushing until we migrate again */
> last_migrated_pfn = 0;
> @@ -1678,8 +1676,8 @@ static enum compact_result compact_zone(struct zone
> *zone, struct compact_contro
> * Only go back, not forward. The cached pfn might have been
> * already reset to zone end in compact_finished()
> */
> - if (free_pfn > zone->compact_cached_free_pfn)
> - zone->compact_cached_free_pfn = free_pfn;
> + if (free_pfn > cc->zone->compact_cached_free_pfn)
> + cc->zone->compact_cached_free_pfn = free_pfn;
> }
>
> count_compact_events(COMPACTMIGRATE_SCANNED, cc->total_migrate_scanned);
> @@ -1716,7 +1714,7 @@ static enum compact_result compact_zone_order(struct
> zone *zone, int order,
> INIT_LIST_HEAD(&cc.freepages);
> INIT_LIST_HEAD(&cc.migratepages);
>
> - ret = compact_zone(zone, &cc);
> + ret = compact_zone(&cc);
>
> VM_BUG_ON(!list_empty(&cc.freepages));
> VM_BUG_ON(!list_empty(&cc.migratepages));
> @@ -1834,7 +1832,7 @@ static void compact_node(int nid)
> INIT_LIST_HEAD(&cc.freepages);
> INIT_LIST_HEAD(&cc.migratepages);
>
> - compact_zone(zone, &cc);
> + compact_zone(&cc);
>
> VM_BUG_ON(!list_empty(&cc.freepages));
> VM_BUG_ON(!list_empty(&cc.migratepages));
> @@ -1976,7 +1974,7 @@ static void kcompactd_do_work(pg_data_t *pgdat)
>
> if (kthread_should_stop())
> return;
> - status = compact_zone(zone, &cc);
> + status = compact_zone(&cc);
>
> if (status == COMPACT_SUCCESS) {
> compaction_defer_reset(zone, cc.order, false);
>
