Hierarchically aggregate all memcgs' MGLRU generations and their
page counts into working set page age histograms.
The histograms break down the system's working set per-node,
per-anon/file.
The sysfs interfaces are as follows:
/sys/devices/system/node/nodeX/page_age
A per-node page age histogram, showing an aggregate of the
node's lruvecs. The information is extracted from MGLRU's
per-generation page counters. Reading this file causes a
hierarchical aging of all lruvecs, scanning pages and creates a
new generation in each lruvec.
For example:
1000 anon=0 file=0
2000 anon=0 file=0
100000 anon=5533696 file=5566464
18446744073709551615 anon=0 file=0
/sys/devices/system/node/nodeX/page_age_interval
A comma separated list of time in milliseconds that configures
what the page age histogram uses for aggregation.
Signed-off-by: Yuanchu Xie <[email protected]>
---
drivers/base/node.c | 3 +
include/linux/mmzone.h | 4 +
include/linux/workingset_report.h | 69 +++++
mm/Kconfig | 9 +
mm/Makefile | 1 +
mm/internal.h | 9 +
mm/memcontrol.c | 2 +
mm/mmzone.c | 2 +
mm/vmscan.c | 34 ++-
mm/workingset_report.c | 413 ++++++++++++++++++++++++++++++
10 files changed, 545 insertions(+), 1 deletion(-)
create mode 100644 include/linux/workingset_report.h
create mode 100644 mm/workingset_report.c
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 1c05640461dd..4f589b8253f4 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -20,6 +20,7 @@
#include <linux/pm_runtime.h>
#include <linux/swap.h>
#include <linux/slab.h>
+#include <linux/workingset_report.h>
static const struct bus_type node_subsys = {
.name = "node",
@@ -625,6 +626,7 @@ static int register_node(struct node *node, int num)
} else {
hugetlb_register_node(node);
compaction_register_node(node);
+ wsr_register_node(node);
}
return error;
@@ -641,6 +643,7 @@ void unregister_node(struct node *node)
{
hugetlb_unregister_node(node);
compaction_unregister_node(node);
+ wsr_unregister_node(node);
node_remove_accesses(node);
node_remove_caches(node);
device_unregister(&node->dev);
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index a497f189d988..8839931646ee 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -24,6 +24,7 @@
#include <linux/local_lock.h>
#include <linux/zswap.h>
#include <asm/page.h>
+#include <linux/workingset_report.h>
/* Free memory management - zoned buddy allocator. */
#ifndef CONFIG_ARCH_FORCE_MAX_ORDER
@@ -625,6 +626,9 @@ struct lruvec {
struct lru_gen_mm_state mm_state;
#endif
#endif /* CONFIG_LRU_GEN */
+#ifdef CONFIG_WORKINGSET_REPORT
+ struct wsr_state wsr;
+#endif /* CONFIG_WORKINGSET_REPORT */
#ifdef CONFIG_MEMCG
struct pglist_data *pgdat;
#endif
diff --git a/include/linux/workingset_report.h b/include/linux/workingset_report.h
new file mode 100644
index 000000000000..0de640cb1ef0
--- /dev/null
+++ b/include/linux/workingset_report.h
@@ -0,0 +1,69 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_WORKINGSET_REPORT_H
+#define _LINUX_WORKINGSET_REPORT_H
+
+#include <linux/types.h>
+#include <linux/mutex.h>
+
+struct mem_cgroup;
+struct pglist_data;
+struct node;
+struct lruvec;
+
+#ifdef CONFIG_WORKINGSET_REPORT
+
+#define WORKINGSET_REPORT_MIN_NR_BINS 2
+#define WORKINGSET_REPORT_MAX_NR_BINS 32
+
+#define WORKINGSET_INTERVAL_MAX ((unsigned long)-1)
+#define ANON_AND_FILE 2
+
+struct wsr_report_bin {
+ unsigned long idle_age;
+ unsigned long nr_pages[ANON_AND_FILE];
+};
+
+struct wsr_report_bins {
+ unsigned long nr_bins;
+ /* last bin contains WORKINGSET_INTERVAL_MAX */
+ struct wsr_report_bin bins[WORKINGSET_REPORT_MAX_NR_BINS];
+};
+
+struct wsr_page_age_histo {
+ unsigned long timestamp;
+ struct wsr_report_bins bins;
+};
+
+struct wsr_state {
+ /* breakdown of workingset by page age */
+ struct mutex page_age_lock;
+ struct wsr_page_age_histo *page_age;
+};
+
+void wsr_init(struct lruvec *lruvec);
+void wsr_destroy(struct lruvec *lruvec);
+
+/*
+ * Returns true if the wsr is configured to be refreshed.
+ * The next refresh time is stored in refresh_time.
+ */
+bool wsr_refresh_report(struct wsr_state *wsr, struct mem_cgroup *root,
+ struct pglist_data *pgdat);
+void wsr_register_node(struct node *node);
+void wsr_unregister_node(struct node *node);
+#else
+static inline void wsr_init(struct lruvec *lruvec)
+{
+}
+static inline void wsr_destroy(struct lruvec *lruvec)
+{
+}
+static inline void wsr_register_node(struct node *node)
+{
+}
+static inline void wsr_unregister_node(struct node *node)
+{
+}
+#endif /* CONFIG_WORKINGSET_REPORT */
+
+#endif /* _LINUX_WORKINGSET_REPORT_H */
diff --git a/mm/Kconfig b/mm/Kconfig
index ffc3a2ba3a8c..212f203b10b9 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -1261,6 +1261,15 @@ config LOCK_MM_AND_FIND_VMA
config IOMMU_MM_DATA
bool
+config WORKINGSET_REPORT
+ bool "Working set reporting"
+ depends on LRU_GEN && SYSFS
+ help
+ Report system and per-memcg working set to userspace.
+
+ This option exports stats and events giving the user more insight
+ into its memory working set.
+
source "mm/damon/Kconfig"
endmenu
diff --git a/mm/Makefile b/mm/Makefile
index e4b5b75aaec9..57093657030d 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -92,6 +92,7 @@ obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o
obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o
+obj-$(CONFIG_WORKINGSET_REPORT) += workingset_report.o
ifdef CONFIG_SWAP
obj-$(CONFIG_MEMCG) += swap_cgroup.o
endif
diff --git a/mm/internal.h b/mm/internal.h
index f309a010d50f..5e0caba64ee4 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -198,12 +198,21 @@ extern unsigned long highest_memmap_pfn;
/*
* in mm/vmscan.c:
*/
+struct scan_control;
bool isolate_lru_page(struct page *page);
bool folio_isolate_lru(struct folio *folio);
void putback_lru_page(struct page *page);
void folio_putback_lru(struct folio *folio);
extern void reclaim_throttle(pg_data_t *pgdat, enum vmscan_throttle_state reason);
+#ifdef CONFIG_WORKINGSET_REPORT
+/*
+ * in mm/wsr.c
+ */
+/* Requires wsr->page_age_lock held */
+void wsr_refresh_scan(struct lruvec *lruvec);
+#endif
+
/*
* in mm/rmap.c:
*/
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1ed40f9d3a27..2f07141de16c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -65,6 +65,7 @@
#include <linux/seq_buf.h>
#include <linux/sched/isolation.h>
#include <linux/kmemleak.h>
+#include <linux/workingset_report.h>
#include "internal.h"
#include <net/sock.h>
#include <net/ip.h>
@@ -5457,6 +5458,7 @@ static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
if (!pn)
return;
+ wsr_destroy(&pn->lruvec);
free_percpu(pn->lruvec_stats_percpu);
kfree(pn);
}
diff --git a/mm/mmzone.c b/mm/mmzone.c
index c01896eca736..efca44c1b84b 100644
--- a/mm/mmzone.c
+++ b/mm/mmzone.c
@@ -90,6 +90,8 @@ void lruvec_init(struct lruvec *lruvec)
*/
list_del(&lruvec->lists[LRU_UNEVICTABLE]);
+ wsr_init(lruvec);
+
lru_gen_init_lruvec(lruvec);
}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 1a7c7d537db6..b694d80ab2d1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -56,6 +56,7 @@
#include <linux/khugepaged.h>
#include <linux/rculist_nulls.h>
#include <linux/random.h>
+#include <linux/workingset_report.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -3815,7 +3816,7 @@ static bool inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
return success;
}
-static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
+bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
struct scan_control *sc, bool can_swap, bool force_scan)
{
bool success;
@@ -5606,6 +5607,8 @@ static int __init init_lru_gen(void)
if (sysfs_create_group(mm_kobj, &lru_gen_attr_group))
pr_err("lru_gen: failed to create sysfs group\n");
+ wsr_register_node(NULL);
+
debugfs_create_file("lru_gen", 0644, NULL, NULL, &lru_gen_rw_fops);
debugfs_create_file("lru_gen_full", 0444, NULL, NULL, &lru_gen_ro_fops);
@@ -5613,6 +5616,35 @@ static int __init init_lru_gen(void)
};
late_initcall(init_lru_gen);
+/******************************************************************************
+ * workingset reporting
+ ******************************************************************************/
+#ifdef CONFIG_WORKINGSET_REPORT
+void wsr_refresh_scan(struct lruvec *lruvec)
+{
+ DEFINE_MAX_SEQ(lruvec);
+ struct scan_control sc = {
+ .may_writepage = true,
+ .may_unmap = true,
+ .may_swap = true,
+ .proactive = true,
+ .reclaim_idx = MAX_NR_ZONES - 1,
+ .gfp_mask = GFP_KERNEL,
+ };
+ unsigned int flags;
+
+ set_task_reclaim_state(current, &sc.reclaim_state);
+ flags = memalloc_noreclaim_save();
+ /*
+ * setting can_swap=true and force_scan=true ensures
+ * proper workingset stats when the system cannot swap.
+ */
+ try_to_inc_max_seq(lruvec, max_seq, &sc, true, true);
+ memalloc_noreclaim_restore(flags);
+ set_task_reclaim_state(current, NULL);
+}
+#endif /* CONFIG_WORKINGSET_REPORT */
+
#else /* !CONFIG_LRU_GEN */
static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc)
diff --git a/mm/workingset_report.c b/mm/workingset_report.c
new file mode 100644
index 000000000000..98cdaffcb6b4
--- /dev/null
+++ b/mm/workingset_report.c
@@ -0,0 +1,413 @@
+// SPDX-License-Identifier: GPL-2.0
+//
+#include <linux/export.h>
+#include <linux/lockdep.h>
+#include <linux/jiffies.h>
+#include <linux/kernfs.h>
+#include <linux/memcontrol.h>
+#include <linux/rcupdate.h>
+#include <linux/mutex.h>
+#include <linux/err.h>
+#include <linux/atomic.h>
+#include <linux/node.h>
+#include <linux/mmzone.h>
+#include <linux/mm.h>
+#include <linux/mm_inline.h>
+#include <linux/workingset_report.h>
+
+#include "internal.h"
+
+void wsr_init(struct lruvec *lruvec)
+{
+ struct wsr_state *wsr = &lruvec->wsr;
+
+ memset(wsr, 0, sizeof(*wsr));
+ mutex_init(&wsr->page_age_lock);
+}
+
+void wsr_destroy(struct lruvec *lruvec)
+{
+ struct wsr_state *wsr = &lruvec->wsr;
+
+ mutex_destroy(&wsr->page_age_lock);
+ kfree(wsr->page_age);
+ memset(wsr, 0, sizeof(*wsr));
+}
+
+static int workingset_report_intervals_parse(char *src,
+ struct wsr_report_bins *bins)
+{
+ int err = 0, i = 0;
+ char *cur, *next = strim(src);
+
+ if (*next == '\0')
+ return 0;
+
+ while ((cur = strsep(&next, ","))) {
+ unsigned int interval;
+
+ err = kstrtouint(cur, 0, &interval);
+ if (err)
+ goto out;
+
+ bins->bins[i].idle_age = msecs_to_jiffies(interval);
+ if (i > 0 && bins->bins[i].idle_age <= bins->bins[i - 1].idle_age) {
+ err = -EINVAL;
+ goto out;
+ }
+
+ if (++i == WORKINGSET_REPORT_MAX_NR_BINS) {
+ err = -ERANGE;
+ goto out;
+ }
+ }
+
+ if (i && i < WORKINGSET_REPORT_MIN_NR_BINS - 1) {
+ err = -ERANGE;
+ goto out;
+ }
+
+ bins->nr_bins = i;
+ bins->bins[i].idle_age = WORKINGSET_INTERVAL_MAX;
+out:
+ return err ?: i;
+}
+
+static unsigned long get_gen_start_time(const struct lru_gen_folio *lrugen,
+ unsigned long seq,
+ unsigned long max_seq,
+ unsigned long curr_timestamp)
+{
+ int younger_gen;
+
+ if (seq == max_seq)
+ return curr_timestamp;
+ younger_gen = lru_gen_from_seq(seq + 1);
+ return READ_ONCE(lrugen->timestamps[younger_gen]);
+}
+
+static void collect_page_age_type(const struct lru_gen_folio *lrugen,
+ struct wsr_report_bin *bin,
+ unsigned long max_seq, unsigned long min_seq,
+ unsigned long curr_timestamp, int type)
+{
+ unsigned long seq;
+
+ for (seq = max_seq; seq + 1 > min_seq; seq--) {
+ int gen, zone;
+ unsigned long gen_end, gen_start, size = 0;
+
+ gen = lru_gen_from_seq(seq);
+
+ for (zone = 0; zone < MAX_NR_ZONES; zone++)
+ size += max(
+ READ_ONCE(lrugen->nr_pages[gen][type][zone]),
+ 0L);
+
+ gen_start = get_gen_start_time(lrugen, seq, max_seq,
+ curr_timestamp);
+ gen_end = READ_ONCE(lrugen->timestamps[gen]);
+
+ while (bin->idle_age != WORKINGSET_INTERVAL_MAX &&
+ time_before(gen_end + bin->idle_age, curr_timestamp)) {
+ unsigned long gen_in_bin = (long)gen_start -
+ (long)curr_timestamp +
+ (long)bin->idle_age;
+ unsigned long gen_len = (long)gen_start - (long)gen_end;
+
+ if (!gen_len)
+ break;
+ if (gen_in_bin) {
+ unsigned long split_bin =
+ size / gen_len * gen_in_bin;
+
+ bin->nr_pages[type] += split_bin;
+ size -= split_bin;
+ }
+ gen_start = curr_timestamp - bin->idle_age;
+ bin++;
+ }
+ bin->nr_pages[type] += size;
+ }
+}
+
+/*
+ * proportionally aggregate Multi-gen LRU bins into a working set report
+ * MGLRU generations:
+ * current time
+ * | max_seq timestamp
+ * | | max_seq - 1 timestamp
+ * | | | unbounded
+ * | | | |
+ * --------------------------------
+ * | max_seq | ... | ... | min_seq
+ * --------------------------------
+ *
+ * Bins:
+ *
+ * current time
+ * | current - idle_age[0]
+ * | | current - idle_age[1]
+ * | | | unbounded
+ * | | | |
+ * ------------------------------
+ * | bin 0 | ... | ... | bin n-1
+ * ------------------------------
+ *
+ * Assume the heuristic that pages are in the MGLRU generation
+ * through uniform accesses, so we can aggregate them
+ * proportionally into bins.
+ */
+static void collect_page_age(struct wsr_page_age_histo *page_age,
+ const struct lruvec *lruvec)
+{
+ int type;
+ const struct lru_gen_folio *lrugen = &lruvec->lrugen;
+ unsigned long curr_timestamp = jiffies;
+ unsigned long max_seq = READ_ONCE((lruvec)->lrugen.max_seq);
+ unsigned long min_seq[ANON_AND_FILE] = {
+ READ_ONCE(lruvec->lrugen.min_seq[LRU_GEN_ANON]),
+ READ_ONCE(lruvec->lrugen.min_seq[LRU_GEN_FILE]),
+ };
+ struct wsr_report_bins *bins = &page_age->bins;
+
+ for (type = 0; type < ANON_AND_FILE; type++) {
+ struct wsr_report_bin *bin = &bins->bins[0];
+
+ collect_page_age_type(lrugen, bin, max_seq, min_seq[type],
+ curr_timestamp, type);
+ }
+}
+
+/* First step: hierarchically scan child memcgs. */
+static void refresh_scan(struct wsr_state *wsr, struct mem_cgroup *root,
+ struct pglist_data *pgdat)
+{
+ struct mem_cgroup *memcg;
+
+ memcg = mem_cgroup_iter(root, NULL, NULL);
+ do {
+ struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
+
+ wsr_refresh_scan(lruvec);
+ cond_resched();
+ } while ((memcg = mem_cgroup_iter(root, memcg, NULL)));
+}
+
+/* Second step: aggregate child memcgs into the page age histogram. */
+static void refresh_aggregate(struct wsr_page_age_histo *page_age,
+ struct mem_cgroup *root,
+ struct pglist_data *pgdat)
+{
+ struct mem_cgroup *memcg;
+ struct wsr_report_bin *bin;
+
+ /*
+ * page_age_intervals should free the page_age struct
+ * if no intervals are provided.
+ */
+ VM_WARN_ON_ONCE(page_age->bins.bins[0].idle_age ==
+ WORKINGSET_INTERVAL_MAX);
+
+ for (bin = page_age->bins.bins;
+ bin->idle_age != WORKINGSET_INTERVAL_MAX; bin++) {
+ bin->nr_pages[0] = 0;
+ bin->nr_pages[1] = 0;
+ }
+ /* the last used bin has idle_age == WORKINGSET_INTERVAL_MAX. */
+ bin->nr_pages[0] = 0;
+ bin->nr_pages[1] = 0;
+
+ memcg = mem_cgroup_iter(root, NULL, NULL);
+ do {
+ struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
+
+ collect_page_age(page_age, lruvec);
+ cond_resched();
+ } while ((memcg = mem_cgroup_iter(root, memcg, NULL)));
+ WRITE_ONCE(page_age->timestamp, jiffies);
+}
+
+bool wsr_refresh_report(struct wsr_state *wsr, struct mem_cgroup *root,
+ struct pglist_data *pgdat)
+{
+ struct wsr_page_age_histo *page_age;
+
+ if (!READ_ONCE(wsr->page_age))
+ return false;
+
+ refresh_scan(wsr, root, pgdat);
+ mutex_lock(&wsr->page_age_lock);
+ page_age = READ_ONCE(wsr->page_age);
+ if (page_age)
+ refresh_aggregate(page_age, root, pgdat);
+ mutex_unlock(&wsr->page_age_lock);
+ return !!page_age;
+}
+EXPORT_SYMBOL_GPL(wsr_refresh_report);
+
+static struct pglist_data *kobj_to_pgdat(struct kobject *kobj)
+{
+ int nid = IS_ENABLED(CONFIG_NUMA) ? kobj_to_dev(kobj)->id :
+ first_memory_node;
+
+ return NODE_DATA(nid);
+}
+
+static struct wsr_state *kobj_to_wsr(struct kobject *kobj)
+{
+ return &mem_cgroup_lruvec(NULL, kobj_to_pgdat(kobj))->wsr;
+}
+
+static ssize_t page_age_intervals_show(struct kobject *kobj,
+ struct kobj_attribute *attr, char *buf)
+{
+ int len = 0;
+ struct wsr_state *wsr = kobj_to_wsr(kobj);
+
+ mutex_lock(&wsr->page_age_lock);
+
+ if (!!wsr->page_age) {
+ int i;
+ int nr_bins = wsr->page_age->bins.nr_bins;
+
+ for (i = 0; i < nr_bins; ++i) {
+ struct wsr_report_bin *bin =
+ &wsr->page_age->bins.bins[i];
+
+ len += sysfs_emit_at(buf, len, "%u",
+ jiffies_to_msecs(bin->idle_age));
+ if (i + 1 < nr_bins)
+ len += sysfs_emit_at(buf, len, ",");
+ }
+ }
+ len += sysfs_emit_at(buf, len, "\n");
+
+ mutex_unlock(&wsr->page_age_lock);
+ return len;
+}
+
+static ssize_t page_age_intervals_store(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ const char *src, size_t len)
+{
+ struct wsr_page_age_histo *page_age = NULL, *old;
+ char *buf = NULL;
+ int err = 0;
+ struct wsr_state *wsr = kobj_to_wsr(kobj);
+
+ buf = kstrdup(src, GFP_KERNEL);
+ if (!buf) {
+ err = -ENOMEM;
+ goto failed;
+ }
+
+ page_age =
+ kzalloc(sizeof(struct wsr_page_age_histo), GFP_KERNEL_ACCOUNT);
+
+ if (!page_age) {
+ err = -ENOMEM;
+ goto failed;
+ }
+
+ err = workingset_report_intervals_parse(buf, &page_age->bins);
+ if (err < 0)
+ goto failed;
+
+ if (err == 0) {
+ kfree(page_age);
+ page_age = NULL;
+ }
+
+ mutex_lock(&wsr->page_age_lock);
+ old = xchg(&wsr->page_age, page_age);
+ mutex_unlock(&wsr->page_age_lock);
+ kfree(old);
+ kfree(buf);
+ return len;
+failed:
+ kfree(page_age);
+ kfree(buf);
+
+ return err;
+}
+
+static struct kobj_attribute page_age_intervals_attr =
+ __ATTR_RW(page_age_intervals);
+
+static ssize_t page_age_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ struct wsr_report_bin *bin;
+ int ret = 0;
+ struct wsr_state *wsr = kobj_to_wsr(kobj);
+
+ if (!READ_ONCE(wsr->page_age))
+ return -EINVAL;
+
+ wsr_refresh_report(wsr, NULL, kobj_to_pgdat(kobj));
+
+ mutex_lock(&wsr->page_age_lock);
+ if (!wsr->page_age) {
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ for (bin = wsr->page_age->bins.bins;
+ bin->idle_age != WORKINGSET_INTERVAL_MAX; bin++)
+ ret += sysfs_emit_at(buf, ret, "%u anon=%lu file=%lu\n",
+ jiffies_to_msecs(bin->idle_age),
+ bin->nr_pages[0] * PAGE_SIZE,
+ bin->nr_pages[1] * PAGE_SIZE);
+
+ ret += sysfs_emit_at(buf, ret, "%lu anon=%lu file=%lu\n",
+ WORKINGSET_INTERVAL_MAX,
+ bin->nr_pages[0] * PAGE_SIZE,
+ bin->nr_pages[1] * PAGE_SIZE);
+
+unlock:
+ mutex_unlock(&wsr->page_age_lock);
+ return ret;
+}
+
+static struct kobj_attribute page_age_attr = __ATTR_RO(page_age);
+
+static struct attribute *workingset_report_attrs[] = {
+ &page_age_intervals_attr.attr, &page_age_attr.attr, NULL
+};
+
+static const struct attribute_group workingset_report_attr_group = {
+ .name = "workingset_report",
+ .attrs = workingset_report_attrs,
+};
+
+void wsr_register_node(struct node *node)
+{
+ struct kobject *kobj = node ? &node->dev.kobj : mm_kobj;
+ struct wsr_state *wsr;
+
+ if (IS_ENABLED(CONFIG_NUMA) && !node)
+ return;
+
+ wsr = kobj_to_wsr(kobj);
+
+ if (sysfs_create_group(kobj, &workingset_report_attr_group)) {
+ pr_warn("WSR failed to created group");
+ return;
+ }
+}
+EXPORT_SYMBOL_GPL(wsr_register_node);
+
+void wsr_unregister_node(struct node *node)
+{
+ struct kobject *kobj = &node->dev.kobj;
+ struct wsr_state *wsr;
+
+ if (IS_ENABLED(CONFIG_NUMA) && !node)
+ return;
+
+ wsr = kobj_to_wsr(kobj);
+ sysfs_remove_group(kobj, &workingset_report_attr_group);
+ wsr_destroy(mem_cgroup_lruvec(NULL, kobj_to_pgdat(kobj)));
+}
+EXPORT_SYMBOL_GPL(wsr_unregister_node);
--
2.44.0.396.g6e790dbe36-goog
Yuanchu Xie <[email protected]> writes:
> Hierarchically aggregate all memcgs' MGLRU generations and their
> page counts into working set page age histograms.
> The histograms break down the system's working set per-node,
> per-anon/file.
>
> The sysfs interfaces are as follows:
> /sys/devices/system/node/nodeX/page_age
> A per-node page age histogram, showing an aggregate of the
> node's lruvecs. The information is extracted from MGLRU's
> per-generation page counters. Reading this file causes a
> hierarchical aging of all lruvecs, scanning pages and creates a
> new generation in each lruvec.
> For example:
> 1000 anon=0 file=0
> 2000 anon=0 file=0
> 100000 anon=5533696 file=5566464
> 18446744073709551615 anon=0 file=0
>
> /sys/devices/system/node/nodeX/page_age_interval
> A comma separated list of time in milliseconds that configures
> what the page age histogram uses for aggregation.
>
> Signed-off-by: Yuanchu Xie <[email protected]>
> ---
> drivers/base/node.c | 3 +
> include/linux/mmzone.h | 4 +
> include/linux/workingset_report.h | 69 +++++
> mm/Kconfig | 9 +
> mm/Makefile | 1 +
> mm/internal.h | 9 +
> mm/memcontrol.c | 2 +
> mm/mmzone.c | 2 +
> mm/vmscan.c | 34 ++-
> mm/workingset_report.c | 413 ++++++++++++++++++++++++++++++
> 10 files changed, 545 insertions(+), 1 deletion(-)
> create mode 100644 include/linux/workingset_report.h
> create mode 100644 mm/workingset_report.c
>
> diff --git a/drivers/base/node.c b/drivers/base/node.c
> index 1c05640461dd..4f589b8253f4 100644
> --- a/drivers/base/node.c
> +++ b/drivers/base/node.c
> @@ -20,6 +20,7 @@
> #include <linux/pm_runtime.h>
> #include <linux/swap.h>
> #include <linux/slab.h>
> +#include <linux/workingset_report.h>
>
> static const struct bus_type node_subsys = {
> .name = "node",
> @@ -625,6 +626,7 @@ static int register_node(struct node *node, int num)
> } else {
> hugetlb_register_node(node);
> compaction_register_node(node);
> + wsr_register_node(node);
> }
>
> return error;
> @@ -641,6 +643,7 @@ void unregister_node(struct node *node)
> {
> hugetlb_unregister_node(node);
> compaction_unregister_node(node);
> + wsr_unregister_node(node);
> node_remove_accesses(node);
> node_remove_caches(node);
> device_unregister(&node->dev);
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index a497f189d988..8839931646ee 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -24,6 +24,7 @@
> #include <linux/local_lock.h>
> #include <linux/zswap.h>
> #include <asm/page.h>
> +#include <linux/workingset_report.h>
>
> /* Free memory management - zoned buddy allocator. */
> #ifndef CONFIG_ARCH_FORCE_MAX_ORDER
> @@ -625,6 +626,9 @@ struct lruvec {
> struct lru_gen_mm_state mm_state;
> #endif
> #endif /* CONFIG_LRU_GEN */
> +#ifdef CONFIG_WORKINGSET_REPORT
> + struct wsr_state wsr;
> +#endif /* CONFIG_WORKINGSET_REPORT */
> #ifdef CONFIG_MEMCG
> struct pglist_data *pgdat;
> #endif
> diff --git a/include/linux/workingset_report.h b/include/linux/workingset_report.h
> new file mode 100644
> index 000000000000..0de640cb1ef0
> --- /dev/null
> +++ b/include/linux/workingset_report.h
> @@ -0,0 +1,69 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _LINUX_WORKINGSET_REPORT_H
> +#define _LINUX_WORKINGSET_REPORT_H
> +
> +#include <linux/types.h>
> +#include <linux/mutex.h>
> +
> +struct mem_cgroup;
> +struct pglist_data;
> +struct node;
> +struct lruvec;
> +
> +#ifdef CONFIG_WORKINGSET_REPORT
> +
> +#define WORKINGSET_REPORT_MIN_NR_BINS 2
> +#define WORKINGSET_REPORT_MAX_NR_BINS 32
> +
> +#define WORKINGSET_INTERVAL_MAX ((unsigned long)-1)
> +#define ANON_AND_FILE 2
> +
> +struct wsr_report_bin {
> + unsigned long idle_age;
> + unsigned long nr_pages[ANON_AND_FILE];
> +};
> +
> +struct wsr_report_bins {
> + unsigned long nr_bins;
> + /* last bin contains WORKINGSET_INTERVAL_MAX */
> + struct wsr_report_bin bins[WORKINGSET_REPORT_MAX_NR_BINS];
> +};
> +
> +struct wsr_page_age_histo {
> + unsigned long timestamp;
> + struct wsr_report_bins bins;
> +};
> +
> +struct wsr_state {
> + /* breakdown of workingset by page age */
> + struct mutex page_age_lock;
> + struct wsr_page_age_histo *page_age;
> +};
> +
> +void wsr_init(struct lruvec *lruvec);
> +void wsr_destroy(struct lruvec *lruvec);
> +
> +/*
> + * Returns true if the wsr is configured to be refreshed.
> + * The next refresh time is stored in refresh_time.
> + */
> +bool wsr_refresh_report(struct wsr_state *wsr, struct mem_cgroup *root,
> + struct pglist_data *pgdat);
> +void wsr_register_node(struct node *node);
> +void wsr_unregister_node(struct node *node);
> +#else
> +static inline void wsr_init(struct lruvec *lruvec)
> +{
> +}
> +static inline void wsr_destroy(struct lruvec *lruvec)
> +{
> +}
> +static inline void wsr_register_node(struct node *node)
> +{
> +}
> +static inline void wsr_unregister_node(struct node *node)
> +{
> +}
> +#endif /* CONFIG_WORKINGSET_REPORT */
> +
> +#endif /* _LINUX_WORKINGSET_REPORT_H */
> diff --git a/mm/Kconfig b/mm/Kconfig
> index ffc3a2ba3a8c..212f203b10b9 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -1261,6 +1261,15 @@ config LOCK_MM_AND_FIND_VMA
> config IOMMU_MM_DATA
> bool
>
> +config WORKINGSET_REPORT
> + bool "Working set reporting"
> + depends on LRU_GEN && SYSFS
> + help
> + Report system and per-memcg working set to userspace.
> +
> + This option exports stats and events giving the user more insight
> + into its memory working set.
> +
> source "mm/damon/Kconfig"
>
> endmenu
> diff --git a/mm/Makefile b/mm/Makefile
> index e4b5b75aaec9..57093657030d 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -92,6 +92,7 @@ obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o
> obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o
> obj-$(CONFIG_PAGE_COUNTER) += page_counter.o
> obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o
> +obj-$(CONFIG_WORKINGSET_REPORT) += workingset_report.o
> ifdef CONFIG_SWAP
> obj-$(CONFIG_MEMCG) += swap_cgroup.o
> endif
> diff --git a/mm/internal.h b/mm/internal.h
> index f309a010d50f..5e0caba64ee4 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -198,12 +198,21 @@ extern unsigned long highest_memmap_pfn;
> /*
> * in mm/vmscan.c:
> */
> +struct scan_control;
> bool isolate_lru_page(struct page *page);
> bool folio_isolate_lru(struct folio *folio);
> void putback_lru_page(struct page *page);
> void folio_putback_lru(struct folio *folio);
> extern void reclaim_throttle(pg_data_t *pgdat, enum vmscan_throttle_state reason);
>
> +#ifdef CONFIG_WORKINGSET_REPORT
> +/*
> + * in mm/wsr.c
> + */
> +/* Requires wsr->page_age_lock held */
> +void wsr_refresh_scan(struct lruvec *lruvec);
> +#endif
> +
> /*
> * in mm/rmap.c:
> */
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 1ed40f9d3a27..2f07141de16c 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -65,6 +65,7 @@
> #include <linux/seq_buf.h>
> #include <linux/sched/isolation.h>
> #include <linux/kmemleak.h>
> +#include <linux/workingset_report.h>
> #include "internal.h"
> #include <net/sock.h>
> #include <net/ip.h>
> @@ -5457,6 +5458,7 @@ static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
> if (!pn)
> return;
>
> + wsr_destroy(&pn->lruvec);
> free_percpu(pn->lruvec_stats_percpu);
> kfree(pn);
> }
> diff --git a/mm/mmzone.c b/mm/mmzone.c
> index c01896eca736..efca44c1b84b 100644
> --- a/mm/mmzone.c
> +++ b/mm/mmzone.c
> @@ -90,6 +90,8 @@ void lruvec_init(struct lruvec *lruvec)
> */
> list_del(&lruvec->lists[LRU_UNEVICTABLE]);
>
> + wsr_init(lruvec);
> +
> lru_gen_init_lruvec(lruvec);
> }
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 1a7c7d537db6..b694d80ab2d1 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -56,6 +56,7 @@
> #include <linux/khugepaged.h>
> #include <linux/rculist_nulls.h>
> #include <linux/random.h>
> +#include <linux/workingset_report.h>
>
> #include <asm/tlbflush.h>
> #include <asm/div64.h>
> @@ -3815,7 +3816,7 @@ static bool inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
> return success;
> }
>
> -static bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
> +bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
> struct scan_control *sc, bool can_swap, bool force_scan)
It appears that this change isn't necessary.
> {
> bool success;
> @@ -5606,6 +5607,8 @@ static int __init init_lru_gen(void)
> if (sysfs_create_group(mm_kobj, &lru_gen_attr_group))
> pr_err("lru_gen: failed to create sysfs group\n");
>
> + wsr_register_node(NULL);
> +
> debugfs_create_file("lru_gen", 0644, NULL, NULL, &lru_gen_rw_fops);
> debugfs_create_file("lru_gen_full", 0444, NULL, NULL, &lru_gen_ro_fops);
>
> @@ -5613,6 +5616,35 @@ static int __init init_lru_gen(void)
> };
> late_initcall(init_lru_gen);
>
> +/******************************************************************************
> + * workingset reporting
> + ******************************************************************************/
> +#ifdef CONFIG_WORKINGSET_REPORT
> +void wsr_refresh_scan(struct lruvec *lruvec)
> +{
> + DEFINE_MAX_SEQ(lruvec);
> + struct scan_control sc = {
> + .may_writepage = true,
> + .may_unmap = true,
> + .may_swap = true,
> + .proactive = true,
> + .reclaim_idx = MAX_NR_ZONES - 1,
> + .gfp_mask = GFP_KERNEL,
> + };
> + unsigned int flags;
> +
> + set_task_reclaim_state(current, &sc.reclaim_state);
> + flags = memalloc_noreclaim_save();
> + /*
> + * setting can_swap=true and force_scan=true ensures
> + * proper workingset stats when the system cannot swap.
> + */
> + try_to_inc_max_seq(lruvec, max_seq, &sc, true, true);
> + memalloc_noreclaim_restore(flags);
> + set_task_reclaim_state(current, NULL);
> +}
> +#endif /* CONFIG_WORKINGSET_REPORT */
> +
> #else /* !CONFIG_LRU_GEN */
>
> static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc)
> diff --git a/mm/workingset_report.c b/mm/workingset_report.c
> new file mode 100644
> index 000000000000..98cdaffcb6b4
> --- /dev/null
> +++ b/mm/workingset_report.c
> @@ -0,0 +1,413 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +#include <linux/export.h>
> +#include <linux/lockdep.h>
> +#include <linux/jiffies.h>
> +#include <linux/kernfs.h>
> +#include <linux/memcontrol.h>
> +#include <linux/rcupdate.h>
> +#include <linux/mutex.h>
> +#include <linux/err.h>
> +#include <linux/atomic.h>
> +#include <linux/node.h>
> +#include <linux/mmzone.h>
> +#include <linux/mm.h>
> +#include <linux/mm_inline.h>
> +#include <linux/workingset_report.h>
> +
> +#include "internal.h"
> +
> +void wsr_init(struct lruvec *lruvec)
> +{
> + struct wsr_state *wsr = &lruvec->wsr;
> +
> + memset(wsr, 0, sizeof(*wsr));
> + mutex_init(&wsr->page_age_lock);
> +}
> +
> +void wsr_destroy(struct lruvec *lruvec)
> +{
> + struct wsr_state *wsr = &lruvec->wsr;
> +
> + mutex_destroy(&wsr->page_age_lock);
> + kfree(wsr->page_age);
> + memset(wsr, 0, sizeof(*wsr));
> +}
> +
> +static int workingset_report_intervals_parse(char *src,
> + struct wsr_report_bins *bins)
> +{
> + int err = 0, i = 0;
> + char *cur, *next = strim(src);
> +
> + if (*next == '\0')
> + return 0;
> +
> + while ((cur = strsep(&next, ","))) {
> + unsigned int interval;
> +
> + err = kstrtouint(cur, 0, &interval);
> + if (err)
> + goto out;
> +
> + bins->bins[i].idle_age = msecs_to_jiffies(interval);
> + if (i > 0 && bins->bins[i].idle_age <= bins->bins[i - 1].idle_age) {
> + err = -EINVAL;
> + goto out;
> + }
> +
> + if (++i == WORKINGSET_REPORT_MAX_NR_BINS) {
> + err = -ERANGE;
> + goto out;
> + }
> + }
> +
> + if (i && i < WORKINGSET_REPORT_MIN_NR_BINS - 1) {
> + err = -ERANGE;
> + goto out;
> + }
> +
> + bins->nr_bins = i;
> + bins->bins[i].idle_age = WORKINGSET_INTERVAL_MAX;
> +out:
> + return err ?: i;
> +}
> +
> +static unsigned long get_gen_start_time(const struct lru_gen_folio *lrugen,
> + unsigned long seq,
> + unsigned long max_seq,
> + unsigned long curr_timestamp)
> +{
> + int younger_gen;
> +
> + if (seq == max_seq)
> + return curr_timestamp;
> + younger_gen = lru_gen_from_seq(seq + 1);
> + return READ_ONCE(lrugen->timestamps[younger_gen]);
> +}
> +
> +static void collect_page_age_type(const struct lru_gen_folio *lrugen,
> + struct wsr_report_bin *bin,
> + unsigned long max_seq, unsigned long min_seq,
> + unsigned long curr_timestamp, int type)
> +{
> + unsigned long seq;
> +
> + for (seq = max_seq; seq + 1 > min_seq; seq--) {
> + int gen, zone;
> + unsigned long gen_end, gen_start, size = 0;
> +
> + gen = lru_gen_from_seq(seq);
> +
> + for (zone = 0; zone < MAX_NR_ZONES; zone++)
> + size += max(
> + READ_ONCE(lrugen->nr_pages[gen][type][zone]),
> + 0L);
> +
> + gen_start = get_gen_start_time(lrugen, seq, max_seq,
> + curr_timestamp);
> + gen_end = READ_ONCE(lrugen->timestamps[gen]);
> +
> + while (bin->idle_age != WORKINGSET_INTERVAL_MAX &&
> + time_before(gen_end + bin->idle_age, curr_timestamp)) {
> + unsigned long gen_in_bin = (long)gen_start -
> + (long)curr_timestamp +
> + (long)bin->idle_age;
> + unsigned long gen_len = (long)gen_start - (long)gen_end;
> +
> + if (!gen_len)
> + break;
> + if (gen_in_bin) {
> + unsigned long split_bin =
> + size / gen_len * gen_in_bin;
> +
> + bin->nr_pages[type] += split_bin;
> + size -= split_bin;
> + }
> + gen_start = curr_timestamp - bin->idle_age;
> + bin++;
> + }
> + bin->nr_pages[type] += size;
> + }
> +}
> +
> +/*
> + * proportionally aggregate Multi-gen LRU bins into a working set report
> + * MGLRU generations:
> + * current time
> + * | max_seq timestamp
> + * | | max_seq - 1 timestamp
> + * | | | unbounded
> + * | | | |
> + * --------------------------------
> + * | max_seq | ... | ... | min_seq
> + * --------------------------------
> + *
> + * Bins:
> + *
> + * current time
> + * | current - idle_age[0]
> + * | | current - idle_age[1]
> + * | | | unbounded
> + * | | | |
> + * ------------------------------
> + * | bin 0 | ... | ... | bin n-1
> + * ------------------------------
> + *
> + * Assume the heuristic that pages are in the MGLRU generation
> + * through uniform accesses, so we can aggregate them
> + * proportionally into bins.
> + */
> +static void collect_page_age(struct wsr_page_age_histo *page_age,
> + const struct lruvec *lruvec)
> +{
> + int type;
> + const struct lru_gen_folio *lrugen = &lruvec->lrugen;
> + unsigned long curr_timestamp = jiffies;
> + unsigned long max_seq = READ_ONCE((lruvec)->lrugen.max_seq);
> + unsigned long min_seq[ANON_AND_FILE] = {
> + READ_ONCE(lruvec->lrugen.min_seq[LRU_GEN_ANON]),
> + READ_ONCE(lruvec->lrugen.min_seq[LRU_GEN_FILE]),
> + };
> + struct wsr_report_bins *bins = &page_age->bins;
> +
> + for (type = 0; type < ANON_AND_FILE; type++) {
> + struct wsr_report_bin *bin = &bins->bins[0];
> +
> + collect_page_age_type(lrugen, bin, max_seq, min_seq[type],
> + curr_timestamp, type);
> + }
> +}
> +
> +/* First step: hierarchically scan child memcgs. */
> +static void refresh_scan(struct wsr_state *wsr, struct mem_cgroup *root,
> + struct pglist_data *pgdat)
> +{
> + struct mem_cgroup *memcg;
> +
> + memcg = mem_cgroup_iter(root, NULL, NULL);
> + do {
> + struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
> +
> + wsr_refresh_scan(lruvec);
> + cond_resched();
> + } while ((memcg = mem_cgroup_iter(root, memcg, NULL)));
> +}
> +
> +/* Second step: aggregate child memcgs into the page age histogram. */
> +static void refresh_aggregate(struct wsr_page_age_histo *page_age,
> + struct mem_cgroup *root,
> + struct pglist_data *pgdat)
> +{
> + struct mem_cgroup *memcg;
> + struct wsr_report_bin *bin;
> +
> + /*
> + * page_age_intervals should free the page_age struct
> + * if no intervals are provided.
> + */
> + VM_WARN_ON_ONCE(page_age->bins.bins[0].idle_age ==
> + WORKINGSET_INTERVAL_MAX);
> +
> + for (bin = page_age->bins.bins;
> + bin->idle_age != WORKINGSET_INTERVAL_MAX; bin++) {
> + bin->nr_pages[0] = 0;
> + bin->nr_pages[1] = 0;
> + }
> + /* the last used bin has idle_age == WORKINGSET_INTERVAL_MAX. */
> + bin->nr_pages[0] = 0;
> + bin->nr_pages[1] = 0;
> +
> + memcg = mem_cgroup_iter(root, NULL, NULL);
> + do {
> + struct lruvec *lruvec = mem_cgroup_lruvec(memcg, pgdat);
> +
> + collect_page_age(page_age, lruvec);
> + cond_resched();
> + } while ((memcg = mem_cgroup_iter(root, memcg, NULL)));
> + WRITE_ONCE(page_age->timestamp, jiffies);
> +}
> +
> +bool wsr_refresh_report(struct wsr_state *wsr, struct mem_cgroup *root,
> + struct pglist_data *pgdat)
> +{
> + struct wsr_page_age_histo *page_age;
> +
> + if (!READ_ONCE(wsr->page_age))
> + return false;
> +
> + refresh_scan(wsr, root, pgdat);
> + mutex_lock(&wsr->page_age_lock);
> + page_age = READ_ONCE(wsr->page_age);
> + if (page_age)
> + refresh_aggregate(page_age, root, pgdat);
> + mutex_unlock(&wsr->page_age_lock);
> + return !!page_age;
> +}
> +EXPORT_SYMBOL_GPL(wsr_refresh_report);
> +
> +static struct pglist_data *kobj_to_pgdat(struct kobject *kobj)
> +{
> + int nid = IS_ENABLED(CONFIG_NUMA) ? kobj_to_dev(kobj)->id :
> + first_memory_node;
> +
> + return NODE_DATA(nid);
> +}
> +
> +static struct wsr_state *kobj_to_wsr(struct kobject *kobj)
> +{
> + return &mem_cgroup_lruvec(NULL, kobj_to_pgdat(kobj))->wsr;
> +}
> +
> +static ssize_t page_age_intervals_show(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + int len = 0;
> + struct wsr_state *wsr = kobj_to_wsr(kobj);
> +
> + mutex_lock(&wsr->page_age_lock);
> +
> + if (!!wsr->page_age) {
> + int i;
> + int nr_bins = wsr->page_age->bins.nr_bins;
> +
> + for (i = 0; i < nr_bins; ++i) {
> + struct wsr_report_bin *bin =
> + &wsr->page_age->bins.bins[i];
> +
> + len += sysfs_emit_at(buf, len, "%u",
> + jiffies_to_msecs(bin->idle_age));
> + if (i + 1 < nr_bins)
> + len += sysfs_emit_at(buf, len, ",");
> + }
> + }
> + len += sysfs_emit_at(buf, len, "\n");
> +
> + mutex_unlock(&wsr->page_age_lock);
> + return len;
> +}
> +
> +static ssize_t page_age_intervals_store(struct kobject *kobj,
> + struct kobj_attribute *attr,
> + const char *src, size_t len)
> +{
> + struct wsr_page_age_histo *page_age = NULL, *old;
> + char *buf = NULL;
> + int err = 0;
> + struct wsr_state *wsr = kobj_to_wsr(kobj);
> +
> + buf = kstrdup(src, GFP_KERNEL);
> + if (!buf) {
> + err = -ENOMEM;
> + goto failed;
> + }
> +
> + page_age =
> + kzalloc(sizeof(struct wsr_page_age_histo), GFP_KERNEL_ACCOUNT);
> +
> + if (!page_age) {
> + err = -ENOMEM;
> + goto failed;
> + }
> +
> + err = workingset_report_intervals_parse(buf, &page_age->bins);
> + if (err < 0)
> + goto failed;
> +
> + if (err == 0) {
> + kfree(page_age);
> + page_age = NULL;
> + }
> +
> + mutex_lock(&wsr->page_age_lock);
> + old = xchg(&wsr->page_age, page_age);
> + mutex_unlock(&wsr->page_age_lock);
> + kfree(old);
> + kfree(buf);
> + return len;
> +failed:
> + kfree(page_age);
> + kfree(buf);
> +
> + return err;
> +}
> +
> +static struct kobj_attribute page_age_intervals_attr =
> + __ATTR_RW(page_age_intervals);
> +
> +static ssize_t page_age_show(struct kobject *kobj, struct kobj_attribute *attr,
> + char *buf)
> +{
> + struct wsr_report_bin *bin;
> + int ret = 0;
> + struct wsr_state *wsr = kobj_to_wsr(kobj);
> +
> + if (!READ_ONCE(wsr->page_age))
> + return -EINVAL;
> +
> + wsr_refresh_report(wsr, NULL, kobj_to_pgdat(kobj));
> +
> + mutex_lock(&wsr->page_age_lock);
> + if (!wsr->page_age) {
> + ret = -EINVAL;
> + goto unlock;
> + }
> +
> + for (bin = wsr->page_age->bins.bins;
> + bin->idle_age != WORKINGSET_INTERVAL_MAX; bin++)
> + ret += sysfs_emit_at(buf, ret, "%u anon=%lu file=%lu\n",
> + jiffies_to_msecs(bin->idle_age),
> + bin->nr_pages[0] * PAGE_SIZE,
> + bin->nr_pages[1] * PAGE_SIZE);
> +
> + ret += sysfs_emit_at(buf, ret, "%lu anon=%lu file=%lu\n",
> + WORKINGSET_INTERVAL_MAX,
> + bin->nr_pages[0] * PAGE_SIZE,
> + bin->nr_pages[1] * PAGE_SIZE);
> +
> +unlock:
> + mutex_unlock(&wsr->page_age_lock);
> + return ret;
> +}
> +
> +static struct kobj_attribute page_age_attr = __ATTR_RO(page_age);
> +
> +static struct attribute *workingset_report_attrs[] = {
> + &page_age_intervals_attr.attr, &page_age_attr.attr, NULL
> +};
> +
> +static const struct attribute_group workingset_report_attr_group = {
> + .name = "workingset_report",
> + .attrs = workingset_report_attrs,
> +};
> +
> +void wsr_register_node(struct node *node)
> +{
> + struct kobject *kobj = node ? &node->dev.kobj : mm_kobj;
> + struct wsr_state *wsr;
> +
> + if (IS_ENABLED(CONFIG_NUMA) && !node)
> + return;
> +
> + wsr = kobj_to_wsr(kobj);
> +
> + if (sysfs_create_group(kobj, &workingset_report_attr_group)) {
> + pr_warn("WSR failed to created group");
> + return;
> + }
> +}
> +EXPORT_SYMBOL_GPL(wsr_register_node);
> +
> +void wsr_unregister_node(struct node *node)
> +{
> + struct kobject *kobj = &node->dev.kobj;
> + struct wsr_state *wsr;
> +
> + if (IS_ENABLED(CONFIG_NUMA) && !node)
> + return;
> +
> + wsr = kobj_to_wsr(kobj);
> + sysfs_remove_group(kobj, &workingset_report_attr_group);
> + wsr_destroy(mem_cgroup_lruvec(NULL, kobj_to_pgdat(kobj)));
> +}
> +EXPORT_SYMBOL_GPL(wsr_unregister_node);
--
Best Regards,
Huang, Ying