The atomic DMA pools can dynamically expand based on non-blocking
allocations that need to use it.
Export the sizes of each of these pools, in bytes, through debugfs for
measurement.
Suggested-by: Christoph Hellwig <[email protected]>
Signed-off-by: David Rientjes <[email protected]>
---
kernel/dma/pool.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index cf052314d9e4..3e22022c933b 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -2,6 +2,7 @@
/*
* Copyright (C) 2020 Google LLC
*/
+#include <linux/debugfs.h>
#include <linux/dma-direct.h>
#include <linux/dma-noncoherent.h>
#include <linux/dma-contiguous.h>
@@ -15,6 +16,11 @@
static struct gen_pool *atomic_pool_dma __ro_after_init;
static struct gen_pool *atomic_pool_dma32 __ro_after_init;
static struct gen_pool *atomic_pool_kernel __ro_after_init;
+#ifdef CONFIG_DEBUG_FS
+static unsigned long pool_size_dma;
+static unsigned long pool_size_dma32;
+static unsigned long pool_size_kernel;
+#endif
#define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K
static size_t atomic_pool_size = DEFAULT_DMA_COHERENT_POOL_SIZE;
@@ -29,6 +35,38 @@ static int __init early_coherent_pool(char *p)
}
early_param("coherent_pool", early_coherent_pool);
+#ifdef CONFIG_DEBUG_FS
+static void __init dma_atomic_pool_debugfs_init(void)
+{
+ struct dentry *root;
+
+ root = debugfs_create_dir("dma_pools", NULL);
+ if (IS_ERR_OR_NULL(root))
+ return;
+
+ debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);
+ debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);
+ debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);
+}
+
+static void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
+{
+ if (gfp & __GFP_DMA)
+ pool_size_dma += size;
+ else if (gfp & __GFP_DMA32)
+ pool_size_dma32 += size;
+ else
+ pool_size_kernel += size;
+}
+#else
+static inline void dma_atomic_pool_debugfs_init(void)
+{
+}
+static inline void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
gfp_t gfp)
{
@@ -76,6 +114,7 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
if (ret)
goto encrypt_mapping;
+ dma_atomic_pool_size_add(gfp, pool_size);
return 0;
encrypt_mapping:
@@ -160,6 +199,8 @@ static int __init dma_atomic_pool_init(void)
if (!atomic_pool_dma32)
ret = -ENOMEM;
}
+
+ dma_atomic_pool_debugfs_init();
return ret;
}
postcore_initcall(dma_atomic_pool_init);
On 4/14/20 7:04 PM, David Rientjes wrote:
> The atomic DMA pools can dynamically expand based on non-blocking
> allocations that need to use it.
>
> Export the sizes of each of these pools, in bytes, through debugfs for
> measurement.
>
> Suggested-by: Christoph Hellwig <[email protected]>
> Signed-off-by: David Rientjes <[email protected]>
> ---
> kernel/dma/pool.c | 41 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 41 insertions(+)
>
> diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
> index cf052314d9e4..3e22022c933b 100644
> --- a/kernel/dma/pool.c
> +++ b/kernel/dma/pool.c
> @@ -2,6 +2,7 @@
> /*
> * Copyright (C) 2020 Google LLC
> */
> +#include <linux/debugfs.h>
> #include <linux/dma-direct.h>
> #include <linux/dma-noncoherent.h>
> #include <linux/dma-contiguous.h>
> @@ -15,6 +16,11 @@
> static struct gen_pool *atomic_pool_dma __ro_after_init;
> static struct gen_pool *atomic_pool_dma32 __ro_after_init;
> static struct gen_pool *atomic_pool_kernel __ro_after_init;
> +#ifdef CONFIG_DEBUG_FS
I don't think you need the #ifdef any more unless you just want to save
space. All of the debugfs routines have versions for whether
CONFIG_DEBUG_FS is defined or not.
> +static unsigned long pool_size_dma;
> +static unsigned long pool_size_dma32;
> +static unsigned long pool_size_kernel;
> +#endif
>
> #define DEFAULT_DMA_COHERENT_POOL_SIZE SZ_256K
> static size_t atomic_pool_size = DEFAULT_DMA_COHERENT_POOL_SIZE;
> @@ -29,6 +35,38 @@ static int __init early_coherent_pool(char *p)
> }
> early_param("coherent_pool", early_coherent_pool);
>
> +#ifdef CONFIG_DEBUG_FS
> +static void __init dma_atomic_pool_debugfs_init(void)
> +{
> + struct dentry *root;
> +
> + root = debugfs_create_dir("dma_pools", NULL);
> + if (IS_ERR_OR_NULL(root))
> + return;
I believe GregKH went through and removed a lot of these error checks (see
9e3926df8779 ("xgbe: no need to check return value of debugfs_create
functions") for an example).
Thanks,
Tom
> +
> + debugfs_create_ulong("pool_size_dma", 0400, root, &pool_size_dma);
> + debugfs_create_ulong("pool_size_dma32", 0400, root, &pool_size_dma32);
> + debugfs_create_ulong("pool_size_kernel", 0400, root, &pool_size_kernel);
> +}
> +
> +static void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
> +{
> + if (gfp & __GFP_DMA)
> + pool_size_dma += size;
> + else if (gfp & __GFP_DMA32)
> + pool_size_dma32 += size;
> + else
> + pool_size_kernel += size;
> +}
> +#else
> +static inline void dma_atomic_pool_debugfs_init(void)
> +{
> +}
> +static inline void dma_atomic_pool_size_add(gfp_t gfp, size_t size)
> +{
> +}
> +#endif /* CONFIG_DEBUG_FS */
> +
> static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
> gfp_t gfp)
> {
> @@ -76,6 +114,7 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
> if (ret)
> goto encrypt_mapping;
>
> + dma_atomic_pool_size_add(gfp, pool_size);
> return 0;
>
> encrypt_mapping:
> @@ -160,6 +199,8 @@ static int __init dma_atomic_pool_init(void)
> if (!atomic_pool_dma32)
> ret = -ENOMEM;
> }
> +
> + dma_atomic_pool_debugfs_init();
> return ret;
> }
> postcore_initcall(dma_atomic_pool_init);
>
On Wed, Apr 15, 2020 at 08:45:08AM -0500, Tom Lendacky wrote:
>
>
> On 4/14/20 7:04 PM, David Rientjes wrote:
>> The atomic DMA pools can dynamically expand based on non-blocking
>> allocations that need to use it.
>>
>> Export the sizes of each of these pools, in bytes, through debugfs for
>> measurement.
>>
>> Suggested-by: Christoph Hellwig <[email protected]>
>> Signed-off-by: David Rientjes <[email protected]>
>> ---
>> kernel/dma/pool.c | 41 +++++++++++++++++++++++++++++++++++++++++
>> 1 file changed, 41 insertions(+)
>>
>> diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
>> index cf052314d9e4..3e22022c933b 100644
>> --- a/kernel/dma/pool.c
>> +++ b/kernel/dma/pool.c
>> @@ -2,6 +2,7 @@
>> /*
>> * Copyright (C) 2020 Google LLC
>> */
>> +#include <linux/debugfs.h>
>> #include <linux/dma-direct.h>
>> #include <linux/dma-noncoherent.h>
>> #include <linux/dma-contiguous.h>
>> @@ -15,6 +16,11 @@
>> static struct gen_pool *atomic_pool_dma __ro_after_init;
>> static struct gen_pool *atomic_pool_dma32 __ro_after_init;
>> static struct gen_pool *atomic_pool_kernel __ro_after_init;
>> +#ifdef CONFIG_DEBUG_FS
>
> I don't think you need the #ifdef any more unless you just want to save
> space. All of the debugfs routines have versions for whether
> CONFIG_DEBUG_FS is defined or not.
Agreed. I can fix this up.