[tip: core/debugobjects] debugobjects: Move min/max count into pool struct

From: tip-bot2 for Thomas Gleixner
Date: Tue Oct 15 2024 - 11:38:35 EST


The following commit has been merged into the core/debugobjects branch of tip:

Commit-ID: 96a9a0421c77301f9b551f3460ac04471a3c0612
Gitweb: https://git.kernel.org/tip/96a9a0421c77301f9b551f3460ac04471a3c0612
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Mon, 07 Oct 2024 18:50:08 +02:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Tue, 15 Oct 2024 17:30:32 +02:00

debugobjects: Move min/max count into pool struct

Having the accounting in the datastructure is better in terms of cache
lines and allows more optimizations later on.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Reviewed-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
Link: https://lore.kernel.org/all/20241007164913.831908427@xxxxxxxxxxxxx

---
lib/debugobjects.c | 55 +++++++++++++++++++++++++--------------------
1 file changed, 31 insertions(+), 24 deletions(-)

diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 3d1d973..fbe8f26 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -46,9 +46,14 @@ struct debug_bucket {
struct obj_pool {
struct hlist_head objects;
unsigned int cnt;
+ unsigned int min_cnt;
+ unsigned int max_cnt;
} ____cacheline_aligned;

-static DEFINE_PER_CPU(struct obj_pool, pool_pcpu);
+
+static DEFINE_PER_CPU_ALIGNED(struct obj_pool, pool_pcpu) = {
+ .max_cnt = ODEBUG_POOL_PERCPU_SIZE,
+};

static struct debug_bucket obj_hash[ODEBUG_HASH_SIZE];

@@ -56,8 +61,14 @@ static struct debug_obj obj_static_pool[ODEBUG_POOL_SIZE] __initdata;

static DEFINE_RAW_SPINLOCK(pool_lock);

-static struct obj_pool pool_global;
-static struct obj_pool pool_to_free;
+static struct obj_pool pool_global = {
+ .min_cnt = ODEBUG_POOL_MIN_LEVEL,
+ .max_cnt = ODEBUG_POOL_SIZE,
+};
+
+static struct obj_pool pool_to_free = {
+ .max_cnt = UINT_MAX,
+};

static HLIST_HEAD(pool_boot);

@@ -79,13 +90,9 @@ static int __data_racy debug_objects_fixups __read_mostly;
static int __data_racy debug_objects_warnings __read_mostly;
static bool __data_racy debug_objects_enabled __read_mostly
= CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
-static int debug_objects_pool_size __ro_after_init
- = ODEBUG_POOL_SIZE;
-static int debug_objects_pool_min_level __ro_after_init
- = ODEBUG_POOL_MIN_LEVEL;

-static const struct debug_obj_descr *descr_test __read_mostly;
-static struct kmem_cache *obj_cache __ro_after_init;
+static const struct debug_obj_descr *descr_test __read_mostly;
+static struct kmem_cache *obj_cache __ro_after_init;

/*
* Track numbers of kmem_cache_alloc()/free() calls done.
@@ -124,14 +131,14 @@ static __always_inline unsigned int pool_count(struct obj_pool *pool)
return READ_ONCE(pool->cnt);
}

-static inline bool pool_global_should_refill(void)
+static __always_inline bool pool_should_refill(struct obj_pool *pool)
{
- return READ_ONCE(pool_global.cnt) < debug_objects_pool_min_level;
+ return pool_count(pool) < pool->min_cnt;
}

-static inline bool pool_global_must_refill(void)
+static __always_inline bool pool_must_refill(struct obj_pool *pool)
{
- return READ_ONCE(pool_global.cnt) < (debug_objects_pool_min_level / 2);
+ return pool_count(pool) < pool->min_cnt / 2;
}

static void free_object_list(struct hlist_head *head)
@@ -178,7 +185,7 @@ static void fill_pool_from_freelist(void)
* Recheck with the lock held as the worker thread might have
* won the race and freed the global free list already.
*/
- while (pool_to_free.cnt && (pool_global.cnt < debug_objects_pool_min_level)) {
+ while (pool_to_free.cnt && (pool_global.cnt < pool_global.min_cnt)) {
obj = hlist_entry(pool_to_free.objects.first, typeof(*obj), node);
hlist_del(&obj->node);
WRITE_ONCE(pool_to_free.cnt, pool_to_free.cnt - 1);
@@ -197,11 +204,11 @@ static void fill_pool(void)
* - One other CPU is already allocating
* - the global pool has not reached the critical level yet
*/
- if (!pool_global_must_refill() && atomic_read(&cpus_allocating))
+ if (!pool_must_refill(&pool_global) && atomic_read(&cpus_allocating))
return;

atomic_inc(&cpus_allocating);
- while (pool_global_should_refill()) {
+ while (pool_should_refill(&pool_global)) {
struct debug_obj *new, *last = NULL;
HLIST_HEAD(head);
int cnt;
@@ -337,7 +344,7 @@ static void free_obj_work(struct work_struct *work)
if (!raw_spin_trylock_irqsave(&pool_lock, flags))
return;

- if (pool_global.cnt >= debug_objects_pool_size)
+ if (pool_global.cnt >= pool_global.max_cnt)
goto free_objs;

/*
@@ -347,7 +354,7 @@ static void free_obj_work(struct work_struct *work)
* may be gearing up to use more and more objects, don't free any
* of them until the next round.
*/
- while (pool_to_free.cnt && pool_global.cnt < debug_objects_pool_size) {
+ while (pool_to_free.cnt && pool_global.cnt < pool_global.max_cnt) {
obj = hlist_entry(pool_to_free.objects.first, typeof(*obj), node);
hlist_del(&obj->node);
hlist_add_head(&obj->node, &pool_global.objects);
@@ -408,7 +415,7 @@ static void __free_object(struct debug_obj *obj)
}

raw_spin_lock(&pool_lock);
- work = (pool_global.cnt > debug_objects_pool_size) && obj_cache &&
+ work = (pool_global.cnt > pool_global.max_cnt) && obj_cache &&
(pool_to_free.cnt < ODEBUG_FREE_WORK_MAX);
obj_pool_used--;

@@ -424,7 +431,7 @@ static void __free_object(struct debug_obj *obj)
}
}

- if ((pool_global.cnt > debug_objects_pool_size) &&
+ if ((pool_global.cnt > pool_global.max_cnt) &&
(pool_to_free.cnt < ODEBUG_FREE_WORK_MAX)) {
int i;

@@ -629,13 +636,13 @@ static void debug_objects_fill_pool(void)
if (unlikely(!obj_cache))
return;

- if (likely(!pool_global_should_refill()))
+ if (likely(!pool_should_refill(&pool_global)))
return;

/* Try reusing objects from obj_to_free_list */
fill_pool_from_freelist();

- if (likely(!pool_global_should_refill()))
+ if (likely(!pool_should_refill(&pool_global)))
return;

/*
@@ -1427,8 +1434,8 @@ void __init debug_objects_mem_init(void)
* system.
*/
extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
- debug_objects_pool_size += extras;
- debug_objects_pool_min_level += extras;
+ pool_global.max_cnt += extras;
+ pool_global.min_cnt += extras;

/* Everything worked. Expose the cache */
obj_cache = cache;