memcg: add memory.vmscan_stat
The commit log of 0ae5e89c60c9 ("memcg: count the soft_limit reclaim
in...") says it adds scanning stats to memory.stat file. But it doesn't
because we considered we needed to make a concensus for such new APIs.
This patch is a trial to add memory.scan_stat. This shows
- the number of scanned pages(total, anon, file)
- the number of rotated pages(total, anon, file)
- the number of freed pages(total, anon, file)
- the number of elaplsed time (including sleep/pause time)
for both of direct/soft reclaim.
The biggest difference with oringinal Ying's one is that this file
can be reset by some write, as
# echo 0 ...../memory.scan_stat
Example of output is here. This is a result after make -j 6 kernel
under 300M limit.
[kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.scan_stat
[kamezawa@bluextal ~]$ cat /cgroup/memory/A/memory.vmscan_stat
scanned_pages_by_limit 9471864
scanned_anon_pages_by_limit 6640629
scanned_file_pages_by_limit 2831235
rotated_pages_by_limit 4243974
rotated_anon_pages_by_limit 3971968
rotated_file_pages_by_limit 272006
freed_pages_by_limit 2318492
freed_anon_pages_by_limit 962052
freed_file_pages_by_limit 1356440
elapsed_ns_by_limit 351386416101
scanned_pages_by_system 0
scanned_anon_pages_by_system 0
scanned_file_pages_by_system 0
rotated_pages_by_system 0
rotated_anon_pages_by_system 0
rotated_file_pages_by_system 0
freed_pages_by_system 0
freed_anon_pages_by_system 0
freed_file_pages_by_system 0
elapsed_ns_by_system 0
scanned_pages_by_limit_under_hierarchy 9471864
scanned_anon_pages_by_limit_under_hierarchy 6640629
scanned_file_pages_by_limit_under_hierarchy 2831235
rotated_pages_by_limit_under_hierarchy 4243974
rotated_anon_pages_by_limit_under_hierarchy 3971968
rotated_file_pages_by_limit_under_hierarchy 272006
freed_pages_by_limit_under_hierarchy 2318492
freed_anon_pages_by_limit_under_hierarchy 962052
freed_file_pages_by_limit_under_hierarchy 1356440
elapsed_ns_by_limit_under_hierarchy 351386416101
scanned_pages_by_system_under_hierarchy 0
scanned_anon_pages_by_system_under_hierarchy 0
scanned_file_pages_by_system_under_hierarchy 0
rotated_pages_by_system_under_hierarchy 0
rotated_anon_pages_by_system_under_hierarchy 0
rotated_file_pages_by_system_under_hierarchy 0
freed_pages_by_system_under_hierarchy 0
freed_anon_pages_by_system_under_hierarchy 0
freed_file_pages_by_system_under_hierarchy 0
elapsed_ns_by_system_under_hierarchy 0
total_xxxx is for hierarchy management.
This will be useful for further memcg developments and need to be
developped before we do some complicated rework on LRU/softlimit
management.
This patch adds a new struct memcg_scanrecord into scan_control struct.
sc->nr_scanned at el is not designed for exporting information. For
example, nr_scanned is reset frequentrly and incremented +2 at scanning
mapped pages.
To avoid complexity, I added a new param in scan_control which is for
exporting scanning score.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Andrew Bresticker <abrestic@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 06eb6d9..6f3c598 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -380,7 +380,7 @@
5.2 stat file
-memory.stat file includes following statistics
+5.2.1 memory.stat file includes following statistics
# per-memory cgroup local status
cache - # of bytes of page cache memory.
@@ -438,6 +438,89 @@
file_mapped is accounted only when the memory cgroup is owner of page
cache.)
+5.2.2 memory.vmscan_stat
+
+memory.vmscan_stat includes statistics information for memory scanning and
+freeing, reclaiming. The statistics shows memory scanning information since
+memory cgroup creation and can be reset to 0 by writing 0 as
+
+ #echo 0 > ../memory.vmscan_stat
+
+This file contains following statistics.
+
+[param]_[file_or_anon]_pages_by_[reason]_[under_heararchy]
+[param]_elapsed_ns_by_[reason]_[under_hierarchy]
+
+For example,
+
+ scanned_file_pages_by_limit indicates the number of scanned
+ file pages at vmscan.
+
+Now, 3 parameters are supported
+
+ scanned - the number of pages scanned by vmscan
+ rotated - the number of pages activated at vmscan
+ freed - the number of pages freed by vmscan
+
+If "rotated" is high against scanned/freed, the memcg seems busy.
+
+Now, 2 reason are supported
+
+ limit - the memory cgroup's limit
+ system - global memory pressure + softlimit
+ (global memory pressure not under softlimit is not handled now)
+
+When under_hierarchy is added in the tail, the number indicates the
+total memcg scan of its children and itself.
+
+elapsed_ns is a elapsed time in nanosecond. This may include sleep time
+and not indicates CPU usage. So, please take this as just showing
+latency.
+
+Here is an example.
+
+# cat /cgroup/memory/A/memory.vmscan_stat
+scanned_pages_by_limit 9471864
+scanned_anon_pages_by_limit 6640629
+scanned_file_pages_by_limit 2831235
+rotated_pages_by_limit 4243974
+rotated_anon_pages_by_limit 3971968
+rotated_file_pages_by_limit 272006
+freed_pages_by_limit 2318492
+freed_anon_pages_by_limit 962052
+freed_file_pages_by_limit 1356440
+elapsed_ns_by_limit 351386416101
+scanned_pages_by_system 0
+scanned_anon_pages_by_system 0
+scanned_file_pages_by_system 0
+rotated_pages_by_system 0
+rotated_anon_pages_by_system 0
+rotated_file_pages_by_system 0
+freed_pages_by_system 0
+freed_anon_pages_by_system 0
+freed_file_pages_by_system 0
+elapsed_ns_by_system 0
+scanned_pages_by_limit_under_hierarchy 9471864
+scanned_anon_pages_by_limit_under_hierarchy 6640629
+scanned_file_pages_by_limit_under_hierarchy 2831235
+rotated_pages_by_limit_under_hierarchy 4243974
+rotated_anon_pages_by_limit_under_hierarchy 3971968
+rotated_file_pages_by_limit_under_hierarchy 272006
+freed_pages_by_limit_under_hierarchy 2318492
+freed_anon_pages_by_limit_under_hierarchy 962052
+freed_file_pages_by_limit_under_hierarchy 1356440
+elapsed_ns_by_limit_under_hierarchy 351386416101
+scanned_pages_by_system_under_hierarchy 0
+scanned_anon_pages_by_system_under_hierarchy 0
+scanned_file_pages_by_system_under_hierarchy 0
+rotated_pages_by_system_under_hierarchy 0
+rotated_anon_pages_by_system_under_hierarchy 0
+rotated_file_pages_by_system_under_hierarchy 0
+freed_pages_by_system_under_hierarchy 0
+freed_anon_pages_by_system_under_hierarchy 0
+freed_file_pages_by_system_under_hierarchy 0
+elapsed_ns_by_system_under_hierarchy 0
+
5.3 swappiness
Similar to /proc/sys/vm/swappiness, but affecting a hierarchy of groups only.
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index affd5b1..b966007 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -39,6 +39,16 @@
struct mem_cgroup *mem_cont,
int active, int file);
+struct memcg_scanrecord {
+ struct mem_cgroup *mem; /* scanend memory cgroup */
+ struct mem_cgroup *root; /* scan target hierarchy root */
+ int context; /* scanning context (see memcontrol.c) */
+ unsigned long nr_scanned[2]; /* the number of scanned pages */
+ unsigned long nr_rotated[2]; /* the number of rotated pages */
+ unsigned long nr_freed[2]; /* the number of freed pages */
+ unsigned long elapsed; /* nsec of time elapsed while scanning */
+};
+
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
/*
* All "charge" functions with gfp_mask should use GFP_KERNEL or
@@ -119,6 +129,15 @@
extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
struct task_struct *p);
+extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
+ gfp_t gfp_mask, bool noswap,
+ struct memcg_scanrecord *rec);
+extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
+ gfp_t gfp_mask, bool noswap,
+ struct zone *zone,
+ struct memcg_scanrecord *rec,
+ unsigned long *nr_scanned);
+
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
extern int do_swap_account;
#endif
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 44558b6..91d5fcc 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -251,12 +251,6 @@
/* linux/mm/vmscan.c */
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
gfp_t gfp_mask, nodemask_t *mask);
-extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
- gfp_t gfp_mask, bool noswap);
-extern unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
- gfp_t gfp_mask, bool noswap,
- struct zone *zone,
- unsigned long *nr_scanned);
extern int __isolate_lru_page(struct page *page, int mode, int file);
extern unsigned long shrink_all_memory(unsigned long nr_pages);
extern int vm_swappiness;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index dfeca59..04e505b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -205,6 +205,50 @@
static void mem_cgroup_threshold(struct mem_cgroup *mem);
static void mem_cgroup_oom_notify(struct mem_cgroup *mem);
+enum {
+ SCAN_BY_LIMIT,
+ SCAN_BY_SYSTEM,
+ NR_SCAN_CONTEXT,
+ SCAN_BY_SHRINK, /* not recorded now */
+};
+
+enum {
+ SCAN,
+ SCAN_ANON,
+ SCAN_FILE,
+ ROTATE,
+ ROTATE_ANON,
+ ROTATE_FILE,
+ FREED,
+ FREED_ANON,
+ FREED_FILE,
+ ELAPSED,
+ NR_SCANSTATS,
+};
+
+struct scanstat {
+ spinlock_t lock;
+ unsigned long stats[NR_SCAN_CONTEXT][NR_SCANSTATS];
+ unsigned long rootstats[NR_SCAN_CONTEXT][NR_SCANSTATS];
+};
+
+const char *scanstat_string[NR_SCANSTATS] = {
+ "scanned_pages",
+ "scanned_anon_pages",
+ "scanned_file_pages",
+ "rotated_pages",
+ "rotated_anon_pages",
+ "rotated_file_pages",
+ "freed_pages",
+ "freed_anon_pages",
+ "freed_file_pages",
+ "elapsed_ns",
+};
+#define SCANSTAT_WORD_LIMIT "_by_limit"
+#define SCANSTAT_WORD_SYSTEM "_by_system"
+#define SCANSTAT_WORD_HIERARCHY "_under_hierarchy"
+
+
/*
* The memory controller data structure. The memory controller controls both
* page cache and RSS per cgroup. We would eventually like to provide
@@ -270,7 +314,8 @@
/* For oom notifier event fd */
struct list_head oom_notify;
-
+ /* For recording LRU-scan statistics */
+ struct scanstat scanstat;
/*
* Should we move charges of a task when a task is moved into this
* mem_cgroup ? And what type of charges should we move ?
@@ -1623,6 +1668,44 @@
}
#endif
+static void __mem_cgroup_record_scanstat(unsigned long *stats,
+ struct memcg_scanrecord *rec)
+{
+
+ stats[SCAN] += rec->nr_scanned[0] + rec->nr_scanned[1];
+ stats[SCAN_ANON] += rec->nr_scanned[0];
+ stats[SCAN_FILE] += rec->nr_scanned[1];
+
+ stats[ROTATE] += rec->nr_rotated[0] + rec->nr_rotated[1];
+ stats[ROTATE_ANON] += rec->nr_rotated[0];
+ stats[ROTATE_FILE] += rec->nr_rotated[1];
+
+ stats[FREED] += rec->nr_freed[0] + rec->nr_freed[1];
+ stats[FREED_ANON] += rec->nr_freed[0];
+ stats[FREED_FILE] += rec->nr_freed[1];
+
+ stats[ELAPSED] += rec->elapsed;
+}
+
+static void mem_cgroup_record_scanstat(struct memcg_scanrecord *rec)
+{
+ struct mem_cgroup *mem;
+ int context = rec->context;
+
+ if (context >= NR_SCAN_CONTEXT)
+ return;
+
+ mem = rec->mem;
+ spin_lock(&mem->scanstat.lock);
+ __mem_cgroup_record_scanstat(mem->scanstat.stats[context], rec);
+ spin_unlock(&mem->scanstat.lock);
+
+ mem = rec->root;
+ spin_lock(&mem->scanstat.lock);
+ __mem_cgroup_record_scanstat(mem->scanstat.rootstats[context], rec);
+ spin_unlock(&mem->scanstat.lock);
+}
+
/*
* Scan the hierarchy if needed to reclaim memory. We remember the last child
* we reclaimed from, so that we don't end up penalizing one child extensively
@@ -1647,8 +1730,9 @@
bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP;
bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK;
bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT;
+ struct memcg_scanrecord rec;
unsigned long excess;
- unsigned long nr_scanned;
+ unsigned long scanned;
excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
@@ -1656,6 +1740,15 @@
if (!check_soft && !shrink && root_mem->memsw_is_minimum)
noswap = true;
+ if (shrink)
+ rec.context = SCAN_BY_SHRINK;
+ else if (check_soft)
+ rec.context = SCAN_BY_SYSTEM;
+ else
+ rec.context = SCAN_BY_LIMIT;
+
+ rec.root = root_mem;
+
while (1) {
victim = mem_cgroup_select_victim(root_mem);
if (victim == root_mem) {
@@ -1696,14 +1789,23 @@
css_put(&victim->css);
continue;
}
+ rec.mem = victim;
+ rec.nr_scanned[0] = 0;
+ rec.nr_scanned[1] = 0;
+ rec.nr_rotated[0] = 0;
+ rec.nr_rotated[1] = 0;
+ rec.nr_freed[0] = 0;
+ rec.nr_freed[1] = 0;
+ rec.elapsed = 0;
/* we use swappiness of local cgroup */
if (check_soft) {
ret = mem_cgroup_shrink_node_zone(victim, gfp_mask,
- noswap, zone, &nr_scanned);
- *total_scanned += nr_scanned;
+ noswap, zone, &rec, &scanned);
+ *total_scanned += scanned;
} else
ret = try_to_free_mem_cgroup_pages(victim, gfp_mask,
- noswap);
+ noswap, &rec);
+ mem_cgroup_record_scanstat(&rec);
css_put(&victim->css);
/*
* At shrinking usage, we can't check we should stop here or
@@ -3792,14 +3894,18 @@
/* try to free all pages in this cgroup */
shrink = 1;
while (nr_retries && mem->res.usage > 0) {
+ struct memcg_scanrecord rec;
int progress;
if (signal_pending(current)) {
ret = -EINTR;
goto out;
}
+ rec.context = SCAN_BY_SHRINK;
+ rec.mem = mem;
+ rec.root = mem;
progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL,
- false);
+ false, &rec);
if (!progress) {
nr_retries--;
/* maybe some writeback is necessary */
@@ -4643,6 +4749,54 @@
}
#endif /* CONFIG_NUMA */
+static int mem_cgroup_vmscan_stat_read(struct cgroup *cgrp,
+ struct cftype *cft,
+ struct cgroup_map_cb *cb)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
+ char string[64];
+ int i;
+
+ for (i = 0; i < NR_SCANSTATS; i++) {
+ strcpy(string, scanstat_string[i]);
+ strcat(string, SCANSTAT_WORD_LIMIT);
+ cb->fill(cb, string, mem->scanstat.stats[SCAN_BY_LIMIT][i]);
+ }
+
+ for (i = 0; i < NR_SCANSTATS; i++) {
+ strcpy(string, scanstat_string[i]);
+ strcat(string, SCANSTAT_WORD_SYSTEM);
+ cb->fill(cb, string, mem->scanstat.stats[SCAN_BY_SYSTEM][i]);
+ }
+
+ for (i = 0; i < NR_SCANSTATS; i++) {
+ strcpy(string, scanstat_string[i]);
+ strcat(string, SCANSTAT_WORD_LIMIT);
+ strcat(string, SCANSTAT_WORD_HIERARCHY);
+ cb->fill(cb, string, mem->scanstat.rootstats[SCAN_BY_LIMIT][i]);
+ }
+ for (i = 0; i < NR_SCANSTATS; i++) {
+ strcpy(string, scanstat_string[i]);
+ strcat(string, SCANSTAT_WORD_SYSTEM);
+ strcat(string, SCANSTAT_WORD_HIERARCHY);
+ cb->fill(cb, string, mem->scanstat.rootstats[SCAN_BY_SYSTEM][i]);
+ }
+ return 0;
+}
+
+static int mem_cgroup_reset_vmscan_stat(struct cgroup *cgrp,
+ unsigned int event)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
+
+ spin_lock(&mem->scanstat.lock);
+ memset(&mem->scanstat.stats, 0, sizeof(mem->scanstat.stats));
+ memset(&mem->scanstat.rootstats, 0, sizeof(mem->scanstat.rootstats));
+ spin_unlock(&mem->scanstat.lock);
+ return 0;
+}
+
+
static struct cftype mem_cgroup_files[] = {
{
.name = "usage_in_bytes",
@@ -4713,6 +4867,11 @@
.mode = S_IRUGO,
},
#endif
+ {
+ .name = "vmscan_stat",
+ .read_map = mem_cgroup_vmscan_stat_read,
+ .trigger = mem_cgroup_reset_vmscan_stat,
+ },
};
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
@@ -4976,6 +5135,7 @@
atomic_set(&mem->refcnt, 1);
mem->move_charge_at_immigrate = 0;
mutex_init(&mem->thresholds_lock);
+ spin_lock_init(&mem->scanstat.lock);
return &mem->css;
free_out:
__mem_cgroup_free(mem);
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f87702a..7ef6912 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -105,6 +105,7 @@
/* Which cgroup do we reclaim from */
struct mem_cgroup *mem_cgroup;
+ struct memcg_scanrecord *memcg_record;
/*
* Nodemask of nodes allowed by the caller. If NULL, all nodes
@@ -1348,6 +1349,8 @@
int file = is_file_lru(lru);
int numpages = hpage_nr_pages(page);
reclaim_stat->recent_rotated[file] += numpages;
+ if (!scanning_global_lru(sc))
+ sc->memcg_record->nr_rotated[file] += numpages;
}
if (!pagevec_add(&pvec, page)) {
spin_unlock_irq(&zone->lru_lock);
@@ -1391,6 +1394,10 @@
reclaim_stat->recent_scanned[0] += *nr_anon;
reclaim_stat->recent_scanned[1] += *nr_file;
+ if (!scanning_global_lru(sc)) {
+ sc->memcg_record->nr_scanned[0] += *nr_anon;
+ sc->memcg_record->nr_scanned[1] += *nr_file;
+ }
}
/*
@@ -1504,6 +1511,9 @@
nr_reclaimed += shrink_page_list(&page_list, zone, sc);
}
+ if (!scanning_global_lru(sc))
+ sc->memcg_record->nr_freed[file] += nr_reclaimed;
+
local_irq_disable();
if (current_is_kswapd())
__count_vm_events(KSWAPD_STEAL, nr_reclaimed);
@@ -1603,6 +1613,8 @@
}
reclaim_stat->recent_scanned[file] += nr_taken;
+ if (!scanning_global_lru(sc))
+ sc->memcg_record->nr_scanned[file] += nr_taken;
__count_zone_vm_events(PGREFILL, zone, pgscanned);
if (file)
@@ -1654,6 +1666,8 @@
* get_scan_ratio.
*/
reclaim_stat->recent_rotated[file] += nr_rotated;
+ if (!scanning_global_lru(sc))
+ sc->memcg_record->nr_rotated[file] += nr_rotated;
move_active_pages_to_lru(zone, &l_active,
LRU_ACTIVE + file * LRU_FILE);
@@ -2254,9 +2268,10 @@
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
unsigned long mem_cgroup_shrink_node_zone(struct mem_cgroup *mem,
- gfp_t gfp_mask, bool noswap,
- struct zone *zone,
- unsigned long *nr_scanned)
+ gfp_t gfp_mask, bool noswap,
+ struct zone *zone,
+ struct memcg_scanrecord *rec,
+ unsigned long *scanned)
{
struct scan_control sc = {
.nr_scanned = 0,
@@ -2266,7 +2281,9 @@
.may_swap = !noswap,
.order = 0,
.mem_cgroup = mem,
+ .memcg_record = rec,
};
+ unsigned long start, end;
sc.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK);
@@ -2275,6 +2292,7 @@
sc.may_writepage,
sc.gfp_mask);
+ start = sched_clock();
/*
* NOTE: Although we can get the priority field, using it
* here is not a good idea, since it limits the pages we can scan.
@@ -2283,19 +2301,25 @@
* the priority and make it zero.
*/
shrink_zone(0, zone, &sc);
+ end = sched_clock();
+
+ if (rec)
+ rec->elapsed += end - start;
+ *scanned = sc.nr_scanned;
trace_mm_vmscan_memcg_softlimit_reclaim_end(sc.nr_reclaimed);
- *nr_scanned = sc.nr_scanned;
return sc.nr_reclaimed;
}
unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem_cont,
gfp_t gfp_mask,
- bool noswap)
+ bool noswap,
+ struct memcg_scanrecord *rec)
{
struct zonelist *zonelist;
unsigned long nr_reclaimed;
+ unsigned long start, end;
int nid;
struct scan_control sc = {
.may_writepage = !laptop_mode,
@@ -2304,6 +2328,7 @@
.nr_to_reclaim = SWAP_CLUSTER_MAX,
.order = 0,
.mem_cgroup = mem_cont,
+ .memcg_record = rec,
.nodemask = NULL, /* we don't care the placement */
.gfp_mask = (gfp_mask & GFP_RECLAIM_MASK) |
(GFP_HIGHUSER_MOVABLE & ~GFP_RECLAIM_MASK),
@@ -2312,6 +2337,7 @@
.gfp_mask = sc.gfp_mask,
};
+ start = sched_clock();
/*
* Unlike direct reclaim via alloc_pages(), memcg's reclaim doesn't
* take care of from where we get pages. So the node where we start the
@@ -2326,6 +2352,9 @@
sc.gfp_mask);
nr_reclaimed = do_try_to_free_pages(zonelist, &sc, &shrink);
+ end = sched_clock();
+ if (rec)
+ rec->elapsed += end - start;
trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed);
