After reclaiming each node per memcg, it checks mem_cgroup_watermark_ok()
and breaks the priority loop if it returns true. The per-memcg zone will
be marked as "unreclaimable" if the scanning rate is much greater than the
reclaiming rate on the per-memcg LRU. The bit is cleared when there is a
page charged to the memcg being freed. Kswapd breaks the priority loop if
all the zones are marked as "unreclaimable".
changelog v6..v5:
1. make global zone_unreclaimable use the ZONE_MEMCG_RECLAIMABLE_RATE.
2. add comment on the zone_unreclaimable
changelog v5..v4:
1. reduce the frequency of updating mz->unreclaimable bit by using the existing
memcg batch in task struct.
2. add new function mem_cgroup_mz_clear_unreclaimable() for recoganizing zone.
changelog v4..v3:
1. split off from the per-memcg background reclaim patch in V3.
Signed-off-by: Ying Han <yinghan@xxxxxxxxxx>
---
include/linux/memcontrol.h | 40 +++++++++++++++
include/linux/sched.h | 1 +
include/linux/swap.h | 2 +
mm/memcontrol.c | 118 +++++++++++++++++++++++++++++++++++++++++++-
mm/vmscan.c | 25 +++++++++-
5 files changed, 184 insertions(+), 2 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index a4747b0..29bbca2 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -157,6 +157,14 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
gfp_t gfp_mask);
u64 mem_cgroup_get_limit(struct mem_cgroup *mem);
+bool mem_cgroup_zone_reclaimable(struct mem_cgroup *mem, struct zone *zone);
+bool mem_cgroup_mz_unreclaimable(struct mem_cgroup *mem, struct zone *zone);
+void mem_cgroup_mz_set_unreclaimable(struct mem_cgroup *mem, struct zone *zone);
+void mem_cgroup_clear_unreclaimable(struct mem_cgroup *mem, struct page *page);
+void mem_cgroup_mz_clear_unreclaimable(struct mem_cgroup *mem,
+ struct zone *zone);
+void mem_cgroup_mz_pages_scanned(struct mem_cgroup *mem, struct zone* zone,
+ unsigned long nr_scanned);
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail);
@@ -354,6 +362,38 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
{
}
+static inline bool mem_cgroup_zone_reclaimable(struct mem_cgroup *mem,
+ struct zone *zone)
+{
+ return false;
+}
+
+static inline bool mem_cgroup_mz_unreclaimable(struct mem_cgroup *mem,
+ struct zone *zone)
+{
+ return false;
+}
+
+static inline void mem_cgroup_mz_set_unreclaimable(struct mem_cgroup *mem,
+ struct zone *zone)
+{
+}
+
+static inline void mem_cgroup_clear_unreclaimable(struct mem_cgroup *mem,
+ struct page *page)
+{
+}
+
+static inline void mem_cgroup_mz_clear_unreclaimable(struct mem_cgroup *mem,
+ struct zone *zone);
+{
+}
+static inline void mem_cgroup_mz_pages_scanned(struct mem_cgroup *mem,
+ struct zone *zone,
+ unsigned long nr_scanned)
+{
+}
+
static inline
unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
gfp_t gfp_mask)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 98fc7ed..3370c5a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1526,6 +1526,7 @@ struct task_struct {
struct mem_cgroup *memcg; /* target memcg of uncharge */
unsigned long nr_pages; /* uncharged usage */
unsigned long memsw_nr_pages; /* uncharged mem+swap usage */
+ struct zone *zone; /* a zone page is last uncharged */
} memcg_batch;
#endif
};
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 17e0511..319b800 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -160,6 +160,8 @@ enum {
SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
};
+#define ZONE_RECLAIMABLE_RATE 6
+
#define SWAP_CLUSTER_MAX 32
#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7490147..0dfdf27 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -133,7 +133,10 @@ struct mem_cgroup_per_zone {
bool on_tree;
struct mem_cgroup *mem; /* Back pointer, we cannot */
/* use container_of */
+ unsigned long pages_scanned; /* since last reclaim */
+ bool all_unreclaimable; /* All pages pinned */
};
+
/* Macro for accessing counter */
#define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)])
@@ -1154,6 +1157,103 @@ mem_cgroup_get_reclaim_stat_from_page(struct page *page)
return &mz->reclaim_stat;
}
+void mem_cgroup_mz_pages_scanned(struct mem_cgroup *mem, struct zone *zone,
+ unsigned long nr_scanned)
+{
+ struct mem_cgroup_per_zone *mz = NULL;
+ int nid = zone_to_nid(zone);
+ int zid = zone_idx(zone);
+
+ if (!mem)
+ return;
+
+ mz = mem_cgroup_zoneinfo(mem, nid, zid);
+ if (mz)
+ mz->pages_scanned += nr_scanned;
+}
+
+bool mem_cgroup_zone_reclaimable(struct mem_cgroup *mem, struct zone *zone)
+{
+ struct mem_cgroup_per_zone *mz = NULL;
+ int nid = zone_to_nid(zone);
+ int zid = zone_idx(zone);
+
+ if (!mem)
+ return 0;
+
+ mz = mem_cgroup_zoneinfo(mem, nid, zid);
+ if (mz)
+ return mz->pages_scanned <
+ mem_cgroup_zone_reclaimable_pages(mem, zone) *
+ ZONE_RECLAIMABLE_RATE;
+ return 0;
+}
+
+bool mem_cgroup_mz_unreclaimable(struct mem_cgroup *mem, struct zone *zone)
+{
+ struct mem_cgroup_per_zone *mz = NULL;
+ int nid = zone_to_nid(zone);
+ int zid = zone_idx(zone);
+
+ if (!mem)
+ return false;
+
+ mz = mem_cgroup_zoneinfo(mem, nid, zid);
+ if (mz)
+ return mz->all_unreclaimable;
+
+ return false;
+}
+
+void mem_cgroup_mz_set_unreclaimable(struct mem_cgroup *mem, struct zone *zone)
+{
+ struct mem_cgroup_per_zone *mz = NULL;
+ int nid = zone_to_nid(zone);
+ int zid = zone_idx(zone);
+
+ if (!mem)
+ return;
+
+ mz = mem_cgroup_zoneinfo(mem, nid, zid);
+ if (mz)
+ mz->all_unreclaimable = true;
+}
+
+void mem_cgroup_mz_clear_unreclaimable(struct mem_cgroup *mem,
+ struct zone *zone)
+{
+ struct mem_cgroup_per_zone *mz = NULL;
+ int nid = zone_to_nid(zone);
+ int zid = zone_idx(zone);
+
+ if (!mem)
+ return;
+
+ mz = mem_cgroup_zoneinfo(mem, nid, zid);
+ if (mz) {
+ mz->pages_scanned = 0;
+ mz->all_unreclaimable = false;
+ }
+
+ return;
+}
+
+void mem_cgroup_clear_unreclaimable(struct mem_cgroup *mem, struct page *page)
+{
+ struct mem_cgroup_per_zone *mz = NULL;
+
+ if (!mem)
+ return;
+
+ mz = page_cgroup_zoneinfo(mem, page);
+ if (mz) {
+ mz->pages_scanned = 0;
+ mz->all_unreclaimable = false;
+ }
+
+ return;
+}
+
unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
struct list_head *dst,
unsigned long *scanned, int order,
@@ -2701,6 +2801,7 @@ void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem)
static void mem_cgroup_do_uncharge(struct mem_cgroup *mem,
unsigned int nr_pages,
+ struct page *page,
const enum charge_type ctype)
{
struct memcg_batch_info *batch = NULL;
@@ -2718,6 +2819,10 @@ static void mem_cgroup_do_uncharge(struct mem_cgroup *mem,
*/
if (!batch->memcg)
batch->memcg = mem;
+
+ if (!batch->zone)
+ batch->zone = page_zone(page);
+
/*
* do_batch > 0 when unmapping pages or inode invalidate/truncate.
* In those cases, all pages freed continously can be expected to be in
@@ -2739,12 +2844,17 @@ static void mem_cgroup_do_uncharge(struct mem_cgroup *mem,
*/
if (batch->memcg != mem)
goto direct_uncharge;
+
+ if (batch->zone != page_zone(page))
+ mem_cgroup_mz_clear_unreclaimable(mem, page_zone(page));
+
/* remember freed charge and uncharge it later */
batch->nr_pages++;
if (uncharge_memsw)
batch->memsw_nr_pages++;
return;
direct_uncharge:
+ mem_cgroup_mz_clear_unreclaimable(mem, page_zone(page));
res_counter_uncharge(&mem->res, nr_pages * PAGE_SIZE);
if (uncharge_memsw)
res_counter_uncharge(&mem->memsw, nr_pages * PAGE_SIZE);
@@ -2826,7 +2936,7 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
mem_cgroup_get(mem);
}
if (!mem_cgroup_is_root(mem))
- mem_cgroup_do_uncharge(mem, nr_pages, ctype);
+ mem_cgroup_do_uncharge(mem, nr_pages, page, ctype);
return mem;
@@ -2894,6 +3004,10 @@ void mem_cgroup_uncharge_end(void)
if (batch->memsw_nr_pages)
res_counter_uncharge(&batch->memcg->memsw,
batch->memsw_nr_pages * PAGE_SIZE);
+ if (batch->zone)
+ mem_cgroup_mz_clear_unreclaimable(batch->memcg, batch->zone);
+ batch->zone = NULL;
+
memcg_oom_recover(batch->memcg);
/* forget this pointer (for sanity check) */
batch->memcg = NULL;
@@ -4589,6 +4703,8 @@ static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node)
mz->usage_in_excess = 0;
mz->on_tree = false;
mz->mem = mem;
+ mz->pages_scanned = 0;
+ mz->all_unreclaimable = false;
}
return 0;
}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 2a5c734..ed4622b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1414,6 +1414,9 @@ shrink_inactive_list(unsigned long nr_to_scan, struct zone *zone,
ISOLATE_BOTH : ISOLATE_INACTIVE,
zone, sc->mem_cgroup,
0, file);
+
+ mem_cgroup_mz_pages_scanned(sc->mem_cgroup, zone, nr_scanned);
+
/*
* mem_cgroup_isolate_pages() keeps track of
* scanned pages on its own.
@@ -1533,6 +1536,7 @@ static void shrink_active_list(unsigned long nr_pages, struct zone *zone,
* mem_cgroup_isolate_pages() keeps track of
* scanned pages on its own.
*/
+ mem_cgroup_mz_pages_scanned(sc->mem_cgroup, zone, pgscanned);
}
reclaim_stat->recent_scanned[file] += nr_taken;
@@ -1989,7 +1993,8 @@ static void shrink_zones(int priority, struct zonelist *zonelist,
static bool zone_reclaimable(struct zone *zone)
{
- return zone->pages_scanned < zone_reclaimable_pages(zone) * 6;
+ return zone->pages_scanned < zone_reclaimable_pages(zone) *
+ ZONE_RECLAIMABLE_RATE;
}
/*
@@ -2656,10 +2661,20 @@ static void balance_pgdat_node(pg_data_t *pgdat, int order,
if (!scan)
continue;
+ if (mem_cgroup_mz_unreclaimable(mem_cont, zone) &&
+ priority != DEF_PRIORITY)
+ continue;
+
sc->nr_scanned = 0;
shrink_zone(priority, zone, sc);
total_scanned += sc->nr_scanned;
+ if (mem_cgroup_mz_unreclaimable(mem_cont, zone))
+ continue;
+
+ if (!mem_cgroup_zone_reclaimable(mem_cont, zone))
+ mem_cgroup_mz_set_unreclaimable(mem_cont, zone);
+
/*
* If we've done a decent amount of scanning and
* the reclaim ratio is low, start doing writepage
@@ -2736,11 +2751,19 @@ loop_again:
balance_pgdat_node(pgdat, order, &sc);
total_scanned += sc.nr_scanned;
+ /*
+ * Set the node which has at least one reclaimable
+ * zone
+ */
for (i = pgdat->nr_zones - 1; i >= 0; i--) {
struct zone *zone = pgdat->node_zones + i;
if (!populated_zone(zone))
continue;
+
+ if (!mem_cgroup_mz_unreclaimable(mem_cont,
+ zone))
+ break;
}
if (i < 0)
node_clear(nid, do_nodes);
--
1.7.3.1
--
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