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Message-ID: <20241007164914.318776207@linutronix.de>
Date: Mon, 7 Oct 2024 18:50:18 +0200 (CEST)
From: Thomas Gleixner <tglx@...utronix.de>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Zhen Lei <thunder.leizhen@...wei.com>,
Waiman Long <longman@...hat.com>
Subject: [patch 22/25] debugobjects: Move pool statistics into global_pool
struct
Keep it along with the pool as that's a hot cache line anyway and it makes
the code more comprehensible.
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
lib/debugobjects.c | 85 +++++++++++++++++++++++++++++++----------------------
1 file changed, 51 insertions(+), 34 deletions(-)
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -47,11 +47,18 @@ struct debug_bucket {
raw_spinlock_t lock;
};
+struct pool_stats {
+ unsigned int cur_used;
+ unsigned int max_used;
+ unsigned int min_fill;
+};
+
struct obj_pool {
struct hlist_head objects;
unsigned int cnt;
unsigned int min_cnt;
unsigned int max_cnt;
+ struct pool_stats stats;
} ____cacheline_aligned;
@@ -66,8 +73,11 @@ static struct debug_obj obj_static_pool
static DEFINE_RAW_SPINLOCK(pool_lock);
static struct obj_pool pool_global = {
- .min_cnt = ODEBUG_POOL_MIN_LEVEL,
- .max_cnt = ODEBUG_POOL_SIZE,
+ .min_cnt = ODEBUG_POOL_MIN_LEVEL,
+ .max_cnt = ODEBUG_POOL_SIZE,
+ .stats = {
+ .min_fill = ODEBUG_POOL_SIZE,
+ },
};
static struct obj_pool pool_to_free = {
@@ -76,16 +86,6 @@ static struct obj_pool pool_to_free = {
static HLIST_HEAD(pool_boot);
-/*
- * Because of the presence of percpu free pools, obj_pool_free will
- * under-count those in the percpu free pools. Similarly, obj_pool_used
- * will over-count those in the percpu free pools. Adjustments will be
- * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
- * can be off.
- */
-static int __data_racy obj_pool_min_free = ODEBUG_POOL_SIZE;
-static int obj_pool_used;
-static int __data_racy obj_pool_max_used;
static bool obj_freeing;
static int __data_racy debug_objects_maxchain __read_mostly;
@@ -231,6 +231,19 @@ static struct debug_obj *__alloc_object(
return obj;
}
+static void pcpu_refill_stats(void)
+{
+ struct pool_stats *stats = &pool_global.stats;
+
+ WRITE_ONCE(stats->cur_used, stats->cur_used + ODEBUG_BATCH_SIZE);
+
+ if (stats->cur_used > stats->max_used)
+ stats->max_used = stats->cur_used;
+
+ if (pool_global.cnt < stats->min_fill)
+ stats->min_fill = pool_global.cnt;
+}
+
static struct debug_obj *pcpu_alloc(void)
{
struct obj_pool *pcp = this_cpu_ptr(&pool_pcpu);
@@ -250,13 +263,7 @@ static struct debug_obj *pcpu_alloc(void
if (!pool_move_batch(pcp, &pool_global))
return NULL;
}
- obj_pool_used += ODEBUG_BATCH_SIZE;
-
- if (obj_pool_used > obj_pool_max_used)
- obj_pool_max_used = obj_pool_used;
-
- if (pool_global.cnt < obj_pool_min_free)
- obj_pool_min_free = pool_global.cnt;
+ pcpu_refill_stats();
}
}
@@ -285,7 +292,7 @@ static void pcpu_free(struct debug_obj *
/* Try to fit the batch into the pool_global first */
if (!pool_move_batch(&pool_global, pcp))
pool_move_batch(&pool_to_free, pcp);
- obj_pool_used -= ODEBUG_BATCH_SIZE;
+ WRITE_ONCE(pool_global.stats.cur_used, pool_global.stats.cur_used - ODEBUG_BATCH_SIZE);
}
static void free_object_list(struct hlist_head *head)
@@ -1074,23 +1081,33 @@ void debug_check_no_obj_freed(const void
static int debug_stats_show(struct seq_file *m, void *v)
{
- int cpu, obj_percpu_free = 0;
+ unsigned int cpu, pool_used, pcp_free = 0;
+ /*
+ * pool_global.stats.cur_used is the number of batches currently
+ * handed out to per CPU pools. Convert it to number of objects
+ * and subtract the number of free objects in the per CPU pools.
+ * As this is lockless the number is an estimate.
+ */
for_each_possible_cpu(cpu)
- obj_percpu_free += per_cpu(pool_pcpu.cnt, cpu);
+ pcp_free += per_cpu(pool_pcpu.cnt, cpu);
- seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
- seq_printf(m, "max_checked :%d\n", debug_objects_maxchecked);
- seq_printf(m, "warnings :%d\n", debug_objects_warnings);
- seq_printf(m, "fixups :%d\n", debug_objects_fixups);
- seq_printf(m, "pool_free :%d\n", pool_count(&pool_global) + obj_percpu_free);
- seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
- seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
- seq_printf(m, "pool_used :%d\n", obj_pool_used - obj_percpu_free);
- seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
- seq_printf(m, "on_free_list :%d\n", pool_count(&pool_to_free));
- seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
- seq_printf(m, "objs_freed :%d\n", debug_objects_freed);
+ pool_used = data_race(pool_global.stats.cur_used);
+ pcp_free = min(pool_used, pcp_free);
+ pool_used -= pcp_free;
+
+ seq_printf(m, "max_chain : %d\n", debug_objects_maxchain);
+ seq_printf(m, "max_checked : %d\n", debug_objects_maxchecked);
+ seq_printf(m, "warnings : %d\n", debug_objects_warnings);
+ seq_printf(m, "fixups : %d\n", debug_objects_fixups);
+ seq_printf(m, "pool_free : %u\n", pool_count(&pool_global) + pcp_free);
+ seq_printf(m, "pool_pcp_free : %u\n", pcp_free);
+ seq_printf(m, "pool_min_free : %u\n", data_race(pool_global.stats.min_fill));
+ seq_printf(m, "pool_used : %u\n", pool_used);
+ seq_printf(m, "pool_max_used : %u\n", data_race(pool_global.stats.max_used));
+ seq_printf(m, "on_free_list : %u\n", pool_count(&pool_to_free));
+ seq_printf(m, "objs_allocated: %d\n", debug_objects_allocated);
+ seq_printf(m, "objs_freed : %d\n", debug_objects_freed);
return 0;
}
DEFINE_SHOW_ATTRIBUTE(debug_stats);
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