Commit e5b2bc30 authored by Yevgeny Kliteynik's avatar Yevgeny Kliteynik Committed by Saeed Mahameed
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net/mlx5: DR, Cache STE shadow memory 



During rule insertion on each ICM memory chunk we also allocate shadow memory
used for management. This includes the hw_ste, dr_ste and miss list per entry.
Since the scale of these allocations is large we noticed a performance hiccup
that happens once malloc and free are stressed.
In extreme usecases when ~1M chunks are freed at once, it might take up to 40
seconds to complete this, up to the point the kernel sees this as self-detected
stall on CPU:

 rcu: INFO: rcu_sched self-detected stall on CPU

To resolve this we will increase the reuse of shadow memory.
Doing this we see that a time in the aforementioned usecase dropped from ~40
seconds to ~8-10 seconds.

Fixes: 29cf8feb ("net/mlx5: DR, ICM pool memory allocator")
Signed-off-by: default avatarAlex Vesker <valex@nvidia.com>
Signed-off-by: default avatarYevgeny Kliteynik <kliteyn@nvidia.com>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
parent f908a35b

drivers/net/ethernet/mellanox/mlx5/core/steering/dr_icm_pool.c

+74 −35
Original line number Diff line number Diff line
@@ -136,37 +136,35 @@ static void dr_icm_pool_mr_destroy(struct mlx5dr_icm_mr *icm_mr) 
	kvfree(icm_mr);

}



static int dr_icm_chunk_ste_init(struct mlx5dr_icm_chunk *chunk)

static int dr_icm_buddy_get_ste_size(struct mlx5dr_icm_buddy_mem *buddy)

{

	chunk->ste_arr = kvzalloc(chunk->num_of_entries *

				  sizeof(chunk->ste_arr[0]), GFP_KERNEL);

	if (!chunk->ste_arr)

		return -ENOMEM;



	chunk->hw_ste_arr = kvzalloc(chunk->num_of_entries *

				     DR_STE_SIZE_REDUCED, GFP_KERNEL);

	if (!chunk->hw_ste_arr)

		goto out_free_ste_arr;



	chunk->miss_list = kvmalloc(chunk->num_of_entries *

				    sizeof(chunk->miss_list[0]), GFP_KERNEL);

	if (!chunk->miss_list)

		goto out_free_hw_ste_arr;

	/* We support only one type of STE size, both for ConnectX-5 and later

	 * devices. Once the support for match STE which has a larger tag is

	 * added (32B instead of 16B), the STE size for devices later than

	 * ConnectX-5 needs to account for that.

	 */

	return DR_STE_SIZE_REDUCED;

}



	return 0;

static void dr_icm_chunk_ste_init(struct mlx5dr_icm_chunk *chunk, int offset)

{

	struct mlx5dr_icm_buddy_mem *buddy = chunk->buddy_mem;

	int index = offset / DR_STE_SIZE;



out_free_hw_ste_arr:

	kvfree(chunk->hw_ste_arr);

out_free_ste_arr:

	kvfree(chunk->ste_arr);

	return -ENOMEM;

	chunk->ste_arr = &buddy->ste_arr[index];

	chunk->miss_list = &buddy->miss_list[index];

	chunk->hw_ste_arr = buddy->hw_ste_arr +

			    index * dr_icm_buddy_get_ste_size(buddy);

}



static void dr_icm_chunk_ste_cleanup(struct mlx5dr_icm_chunk *chunk)

{

	kvfree(chunk->miss_list);

	kvfree(chunk->hw_ste_arr);

	kvfree(chunk->ste_arr);

	struct mlx5dr_icm_buddy_mem *buddy = chunk->buddy_mem;



	memset(chunk->hw_ste_arr, 0,

	       chunk->num_of_entries * dr_icm_buddy_get_ste_size(buddy));

	memset(chunk->ste_arr, 0,

	       chunk->num_of_entries * sizeof(chunk->ste_arr[0]));

}



static enum mlx5dr_icm_type
@@ -189,6 +187,44 @@ static void dr_icm_chunk_destroy(struct mlx5dr_icm_chunk *chunk, 
	kvfree(chunk);

}



static int dr_icm_buddy_init_ste_cache(struct mlx5dr_icm_buddy_mem *buddy)

{

	int num_of_entries =

		mlx5dr_icm_pool_chunk_size_to_entries(buddy->pool->max_log_chunk_sz);



	buddy->ste_arr = kvcalloc(num_of_entries,

				  sizeof(struct mlx5dr_ste), GFP_KERNEL);

	if (!buddy->ste_arr)

		return -ENOMEM;



	/* Preallocate full STE size on non-ConnectX-5 devices since

	 * we need to support both full and reduced with the same cache.

	 */

	buddy->hw_ste_arr = kvcalloc(num_of_entries,

				     dr_icm_buddy_get_ste_size(buddy), GFP_KERNEL);

	if (!buddy->hw_ste_arr)

		goto free_ste_arr;



	buddy->miss_list = kvmalloc(num_of_entries * sizeof(struct list_head), GFP_KERNEL);

	if (!buddy->miss_list)

		goto free_hw_ste_arr;



	return 0;



free_hw_ste_arr:

	kvfree(buddy->hw_ste_arr);

free_ste_arr:

	kvfree(buddy->ste_arr);

	return -ENOMEM;

}



static void dr_icm_buddy_cleanup_ste_cache(struct mlx5dr_icm_buddy_mem *buddy)

{

	kvfree(buddy->ste_arr);

	kvfree(buddy->hw_ste_arr);

	kvfree(buddy->miss_list);

}



static int dr_icm_buddy_create(struct mlx5dr_icm_pool *pool)

{

	struct mlx5dr_icm_buddy_mem *buddy;
@@ -208,11 +244,19 @@ static int dr_icm_buddy_create(struct mlx5dr_icm_pool *pool) 
	buddy->icm_mr = icm_mr;

	buddy->pool = pool;



	if (pool->icm_type == DR_ICM_TYPE_STE) {

		/* Reduce allocations by preallocating and reusing the STE structures */

		if (dr_icm_buddy_init_ste_cache(buddy))

			goto err_cleanup_buddy;

	}



	/* add it to the -start- of the list in order to search in it first */

	list_add(&buddy->list_node, &pool->buddy_mem_list);



	return 0;



err_cleanup_buddy:

	mlx5dr_buddy_cleanup(buddy);

err_free_buddy:

	kvfree(buddy);

free_mr:
@@ -234,6 +278,9 @@ static void dr_icm_buddy_destroy(struct mlx5dr_icm_buddy_mem *buddy) 


	mlx5dr_buddy_cleanup(buddy);



	if (buddy->pool->icm_type == DR_ICM_TYPE_STE)

		dr_icm_buddy_cleanup_ste_cache(buddy);



	kvfree(buddy);

}
@@ -261,26 +308,18 @@ dr_icm_chunk_create(struct mlx5dr_icm_pool *pool, 
	chunk->byte_size =

		mlx5dr_icm_pool_chunk_size_to_byte(chunk_size, pool->icm_type);

	chunk->seg = seg;

	chunk->buddy_mem = buddy_mem_pool;



	if (pool->icm_type == DR_ICM_TYPE_STE && dr_icm_chunk_ste_init(chunk)) {

		mlx5dr_err(pool->dmn,

			   "Failed to init ste arrays (order: %d)\n",

			   chunk_size);

		goto out_free_chunk;

	}

	if (pool->icm_type == DR_ICM_TYPE_STE)

		dr_icm_chunk_ste_init(chunk, offset);



	buddy_mem_pool->used_memory += chunk->byte_size;

	chunk->buddy_mem = buddy_mem_pool;

	INIT_LIST_HEAD(&chunk->chunk_list);



	/* chunk now is part of the used_list */

	list_add_tail(&chunk->chunk_list, &buddy_mem_pool->used_list);



	return chunk;



out_free_chunk:

	kvfree(chunk);

	return NULL;

}



static bool dr_icm_pool_is_sync_required(struct mlx5dr_icm_pool *pool)

drivers/net/ethernet/mellanox/mlx5/core/steering/mlx5dr.h

+5 −0
Original line number Diff line number Diff line
@@ -160,6 +160,11 @@ struct mlx5dr_icm_buddy_mem { 
	 * sync_ste command sets them free.

	 */

	struct list_head	hot_list;



	/* Memory optimisation */

	struct mlx5dr_ste	*ste_arr;

	struct list_head	*miss_list;

	u8			*hw_ste_arr;

};



int mlx5dr_buddy_init(struct mlx5dr_icm_buddy_mem *buddy,