Refresh threshold is a rate limiting factor to working set
histogram reads. When a working set report is generated, a timestamp
is noted, and the same report will be read until it expires beyond
the refresh threshold, at which point a new report is generated.
Signed-off-by: T.J. Alumbaugh <talumbau@xxxxxxxxxx>
Signed-off-by: Yuanchu Xie <yuanchu@xxxxxxxxxx>
---
include/linux/mmzone.h | 1 +
include/linux/wsr.h | 3 +++
mm/internal.h | 11 +++++++++
mm/vmscan.c | 39 +++++++++++++++++++++++++++++--
mm/wsr.c | 52 +++++++++++++++++++++++++++++++++++++++---
5 files changed, 101 insertions(+), 5 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 96f0d8f3584e4..bca828a16a46b 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -362,6 +362,7 @@ enum lruvec_flags {
#ifndef __GENERATING_BOUNDS_H
+struct node;
struct lruvec;
struct page_vma_mapped_walk;
diff --git a/include/linux/wsr.h b/include/linux/wsr.h
index fa46b4d61177d..a86105468c710 100644
--- a/include/linux/wsr.h
+++ b/include/linux/wsr.h
@@ -26,6 +26,8 @@ struct ws_bin {
struct wsr {
/* protects bins */
struct mutex bins_lock;
+ unsigned long timestamp;
+ unsigned long refresh_threshold;
struct ws_bin bins[MAX_NR_BINS];
};
@@ -40,6 +42,7 @@ ssize_t wsr_intervals_ms_parse(char *src, struct ws_bin *bins);
/*
* wsr->bins needs to be locked
+ * refreshes wsr based on the refresh threshold
*/
void wsr_refresh(struct wsr *wsr, struct mem_cgroup *root,
struct pglist_data *pgdat);
diff --git a/mm/internal.h b/mm/internal.h
index 88dba0b11f663..ce4757e7f8277 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -186,6 +186,17 @@ int 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);
+int get_swappiness(struct lruvec *lruvec, struct scan_control *sc);
+bool try_to_inc_max_seq(struct lruvec *lruvec, unsigned long max_seq,
+ struct scan_control *sc, bool can_swap,
+ bool force_scan);
+
+/*
+ * in mm/wsr.c
+ */
+void refresh_wsr(struct wsr *wsr, struct mem_cgroup *root,
+ struct pglist_data *pgdat, struct scan_control *sc,
+ unsigned long refresh_threshold);
/*
* in mm/rmap.c:
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 150e3cd70c65e..66c5df2a7f65b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3201,7 +3201,7 @@ static struct lruvec *get_lruvec(struct mem_cgroup *memcg, int nid)
return &pgdat->__lruvec;
}
-static int get_swappiness(struct lruvec *lruvec, struct scan_control *sc)
+int get_swappiness(struct lruvec *lruvec, struct scan_control *sc)
{
struct mem_cgroup *memcg = lruvec_memcg(lruvec);
struct pglist_data *pgdat = lruvec_pgdat(lruvec);
@@ -4402,7 +4402,7 @@ static void inc_max_seq(struct lruvec *lruvec, bool can_swap, bool force_scan)
spin_unlock_irq(&lruvec->lru_lock);
}
-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;
@@ -5900,6 +5900,41 @@ static int __init init_lru_gen(void)
};
late_initcall(init_lru_gen);
+/******************************************************************************
+ * working set reporting
+ ******************************************************************************/
+
+#ifdef CONFIG_WSR
+void wsr_refresh(struct wsr *wsr, struct mem_cgroup *root,
+ struct pglist_data *pgdat)
+{
+ unsigned int flags;
+ struct scan_control sc = {
+ .may_writepage = true,
+ .may_unmap = true,
+ .may_swap = true,
+ .reclaim_idx = MAX_NR_ZONES - 1,
+ .gfp_mask = GFP_KERNEL,
+ };
+
+ lockdep_assert_held(&wsr->bins_lock);
+
+ if (wsr->bins->idle_age != -1) {
+ unsigned long timestamp = READ_ONCE(wsr->timestamp);
+ unsigned long threshold = READ_ONCE(wsr->refresh_threshold);
+
+ if (time_is_before_jiffies(timestamp + threshold)) {
+ set_task_reclaim_state(current, &sc.reclaim_state);
+ flags = memalloc_noreclaim_save();
+ refresh_wsr(wsr, root, pgdat, &sc, threshold);
+ memalloc_noreclaim_restore(flags);
+ set_task_reclaim_state(current, NULL);
+ }
+ }
+}
+
+#endif /* CONFIG_WSR */
+
#else /* !CONFIG_LRU_GEN */
static void lru_gen_age_node(struct pglist_data *pgdat, struct scan_control *sc)
diff --git a/mm/wsr.c b/mm/wsr.c
index 1e4c0ce69caf7..ee295d164461e 100644
--- a/mm/wsr.c
+++ b/mm/wsr.c
@@ -125,8 +125,9 @@ static void collect_wsr(struct wsr *wsr, const struct lruvec *lruvec)
}
}
-static void refresh_wsr(struct wsr *wsr, struct mem_cgroup *root,
- struct pglist_data *pgdat)
+void refresh_wsr(struct wsr *wsr, struct mem_cgroup *root,
+ struct pglist_data *pgdat, struct scan_control *sc,
+ unsigned long refresh_threshold)
{
struct ws_bin *bin;
struct mem_cgroup *memcg;
@@ -146,6 +147,24 @@ static void refresh_wsr(struct wsr *wsr, struct mem_cgroup *root,
do {
struct lruvec *lruvec =
mem_cgroup_lruvec(memcg, pgdat);
+ bool can_swap = get_swappiness(lruvec, sc);
+ 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]),
+ };
+
+ mem_cgroup_calculate_protection(root, memcg);
+ if (!mem_cgroup_below_min(root, memcg) && refresh_threshold &&
+ min_seq[!can_swap] + MAX_NR_GENS - 1 > max_seq) {
+ int gen = lru_gen_from_seq(max_seq);
+ unsigned long birth =
+ READ_ONCE(lruvec->lrugen.timestamps[gen]);
+
+ if (time_is_before_jiffies(birth + refresh_threshold))
+ try_to_inc_max_seq(lruvec, max_seq, sc,
+ can_swap, false);
+ }
collect_wsr(wsr, lruvec);
@@ -165,6 +184,32 @@ static struct wsr *kobj_to_wsr(struct kobject *kobj)
return lruvec_wsr(mem_cgroup_lruvec(NULL, kobj_to_pgdat(kobj)));
}
+
+static ssize_t refresh_ms_show(struct kobject *kobj, struct kobj_attribute *attr,
+ char *buf)
+{
+ struct wsr *wsr = kobj_to_wsr(kobj);
+ unsigned long threshold = READ_ONCE(wsr->refresh_threshold);
+
+ return sysfs_emit(buf, "%u\n", jiffies_to_msecs(threshold));
+}
+
+static ssize_t refresh_ms_store(struct kobject *kobj, struct kobj_attribute *attr,
+ const char *buf, size_t len)
+{
+ unsigned int msecs;
+ struct wsr *wsr = kobj_to_wsr(kobj);
+
+ if (kstrtouint(buf, 0, &msecs))
+ return -EINVAL;
+
+ WRITE_ONCE(wsr->refresh_threshold, msecs_to_jiffies(msecs));
+
+ return len;
+}
+
+static struct kobj_attribute refresh_ms_attr = __ATTR_RW(refresh_ms);
+
static ssize_t intervals_ms_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
@@ -227,7 +272,7 @@ static ssize_t histogram_show(struct kobject *kobj, struct kobj_attribute *attr,
mutex_lock(&wsr->bins_lock);
- refresh_wsr(wsr, NULL, kobj_to_pgdat(kobj));
+ wsr_refresh(wsr, NULL, kobj_to_pgdat(kobj));
for (bin = wsr->bins; bin->idle_age != -1; bin++)
len += sysfs_emit_at(buf, len, "%u anon=%lu file=%lu\n",
@@ -245,6 +290,7 @@ static ssize_t histogram_show(struct kobject *kobj, struct kobj_attribute *attr,
static struct kobj_attribute histogram_attr = __ATTR_RO(histogram);
static struct attribute *wsr_attrs[] = {
+ &refresh_ms_attr.attr,
&intervals_ms_attr.attr,
&histogram_attr.attr,
NULL
--
2.41.0.162.gfafddb0af9-goog
