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authorMel Gorman <mgorman@techsingularity.net>2016-07-28 15:45:31 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-28 16:07:41 -0700
commit599d0c954f91d0689c9bb421b5bc04ea02437a41 (patch)
treee863ce685841e494bcb63e458739e0939ac684f6 /mm/memcontrol.c
parenta52633d8e9c35832f1409dc5fa166019048a3f1f (diff)
mm, vmscan: move LRU lists to node
This moves the LRU lists from the zone to the node and related data such as counters, tracing, congestion tracking and writeback tracking. Unfortunately, due to reclaim and compaction retry logic, it is necessary to account for the number of LRU pages on both zone and node logic. Most reclaim logic is based on the node counters but the retry logic uses the zone counters which do not distinguish inactive and active sizes. It would be possible to leave the LRU counters on a per-zone basis but it's a heavier calculation across multiple cache lines that is much more frequent than the retry checks. Other than the LRU counters, this is mostly a mechanical patch but note that it introduces a number of anomalies. For example, the scans are per-zone but using per-node counters. We also mark a node as congested when a zone is congested. This causes weird problems that are fixed later but is easier to review. In the event that there is excessive overhead on 32-bit systems due to the nodes being on LRU then there are two potential solutions 1. Long-term isolation of highmem pages when reclaim is lowmem When pages are skipped, they are immediately added back onto the LRU list. If lowmem reclaim persisted for long periods of time, the same highmem pages get continually scanned. The idea would be that lowmem keeps those pages on a separate list until a reclaim for highmem pages arrives that splices the highmem pages back onto the LRU. It potentially could be implemented similar to the UNEVICTABLE list. That would reduce the skip rate with the potential corner case is that highmem pages have to be scanned and reclaimed to free lowmem slab pages. 2. Linear scan lowmem pages if the initial LRU shrink fails This will break LRU ordering but may be preferable and faster during memory pressure than skipping LRU pages. Link: http://lkml.kernel.org/r/1467970510-21195-4-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c17
1 files changed, 9 insertions, 8 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9b70f9ca8ddf..50c86ad121bc 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -943,14 +943,14 @@ static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
* and putback protocol: the LRU lock must be held, and the page must
* either be PageLRU() or the caller must have isolated/allocated it.
*/
-struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
+struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
{
struct mem_cgroup_per_zone *mz;
struct mem_cgroup *memcg;
struct lruvec *lruvec;
if (mem_cgroup_disabled()) {
- lruvec = &zone->lruvec;
+ lruvec = &pgdat->lruvec;
goto out;
}
@@ -970,8 +970,8 @@ out:
* we have to be prepared to initialize lruvec->zone here;
* and if offlined then reonlined, we need to reinitialize it.
*/
- if (unlikely(lruvec->zone != zone))
- lruvec->zone = zone;
+ if (unlikely(lruvec->pgdat != pgdat))
+ lruvec->pgdat = pgdat;
return lruvec;
}
@@ -979,6 +979,7 @@ out:
* mem_cgroup_update_lru_size - account for adding or removing an lru page
* @lruvec: mem_cgroup per zone lru vector
* @lru: index of lru list the page is sitting on
+ * @zid: Zone ID of the zone pages have been added to
* @nr_pages: positive when adding or negative when removing
*
* This function must be called under lru_lock, just before a page is added
@@ -986,14 +987,14 @@ out:
* so as to allow it to check that lru_size 0 is consistent with list_empty).
*/
void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
- int nr_pages)
+ enum zone_type zid, int nr_pages)
{
struct mem_cgroup_per_zone *mz;
unsigned long *lru_size;
long size;
bool empty;
- __update_lru_size(lruvec, lru, nr_pages);
+ __update_lru_size(lruvec, lru, zid, nr_pages);
if (mem_cgroup_disabled())
return;
@@ -2069,7 +2070,7 @@ static void lock_page_lru(struct page *page, int *isolated)
if (PageLRU(page)) {
struct lruvec *lruvec;
- lruvec = mem_cgroup_page_lruvec(page, zone);
+ lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
ClearPageLRU(page);
del_page_from_lru_list(page, lruvec, page_lru(page));
*isolated = 1;
@@ -2084,7 +2085,7 @@ static void unlock_page_lru(struct page *page, int isolated)
if (isolated) {
struct lruvec *lruvec;
- lruvec = mem_cgroup_page_lruvec(page, zone);
+ lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
VM_BUG_ON_PAGE(PageLRU(page), page);
SetPageLRU(page);
add_page_to_lru_list(page, lruvec, page_lru(page));