diff mbox series

[rdma-next,10/13] RDMA/efa: Add bitmap allocation service

Message ID 1543925069-8838-11-git-send-email-galpress@amazon.com (mailing list archive)
State Changes Requested
Headers show
Series Elastic Fabric Adapter (EFA) driver | expand

Commit Message

Gal Pressman Dec. 4, 2018, 12:04 p.m. UTC 
Bitmap allocation service is currently used for assigning
Protection Domain (PD) numbers.

Signed-off-by: Gal Pressman <galpress@amazon.com>
---
 drivers/infiniband/hw/efa/efa_bitmap.c | 76 ++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 drivers/infiniband/hw/efa/efa_bitmap.c

Comments

Jason Gunthorpe Dec. 4, 2018, 4:03 p.m. UTC | #1 
On Tue, Dec 04, 2018 at 02:04:26PM +0200, Gal Pressman wrote:
> Bitmap allocation service is currently used for assigning
> Protection Domain (PD) numbers.
> 
> Signed-off-by: Gal Pressman <galpress@amazon.com>
>  drivers/infiniband/hw/efa/efa_bitmap.c | 76 ++++++++++++++++++++++++++++++++++
>  1 file changed, 76 insertions(+)
>  create mode 100644 drivers/infiniband/hw/efa/efa_bitmap.c
> 
> diff --git a/drivers/infiniband/hw/efa/efa_bitmap.c b/drivers/infiniband/hw/efa/efa_bitmap.c
> new file mode 100644
> index 000000000000..251cc68d25f5
> +++ b/drivers/infiniband/hw/efa/efa_bitmap.c
> @@ -0,0 +1,76 @@
> +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> +/*
> + * Copyright 2006, 2007 Cisco Systems, Inc.  All rights reserved.
> + * Copyright 2007, 2008 Mellanox Technologies. All rights reserved.
> + * Copyright 2018 Amazon.com, Inc. or its affiliates.
> + */
> +
> +#include <linux/bitmap.h>
> +
> +#include "efa.h"
> +
> +u32 efa_bitmap_alloc(struct efa_bitmap *bitmap)
> +{
> +	u32 obj;
> +
> +	spin_lock(&bitmap->lock);
> +
> +	obj = find_next_zero_bit(bitmap->table, bitmap->max, bitmap->last);
> +	if (obj >= bitmap->max)
> +		obj = find_first_zero_bit(bitmap->table, bitmap->max);
> +
> +	if (obj < bitmap->max) {
> +		set_bit(obj, bitmap->table);
> +		bitmap->last = obj + 1;
> +		if (bitmap->last == bitmap->max)
> +			bitmap->last = 0;
> +	} else {
> +		obj = EFA_BITMAP_INVAL;
> +	}
> +
> +	if (obj != EFA_BITMAP_INVAL)
> +		--bitmap->avail;
> +
> +	spin_unlock(&bitmap->lock);
> +
> +	return obj;
> +}

Isn't this just an ida?

Jason
Gal Pressman Dec. 5, 2018, 8:56 a.m. UTC | #2 
On 04-Dec-18 18:03, Jason Gunthorpe wrote:
> On Tue, Dec 04, 2018 at 02:04:26PM +0200, Gal Pressman wrote:
>> Bitmap allocation service is currently used for assigning
>> Protection Domain (PD) numbers.
>>
>> Signed-off-by: Gal Pressman <galpress@amazon.com>
>>  drivers/infiniband/hw/efa/efa_bitmap.c | 76 ++++++++++++++++++++++++++++++++++
>>  1 file changed, 76 insertions(+)
>>  create mode 100644 drivers/infiniband/hw/efa/efa_bitmap.c
>>
>> diff --git a/drivers/infiniband/hw/efa/efa_bitmap.c b/drivers/infiniband/hw/efa/efa_bitmap.c
>> new file mode 100644
>> index 000000000000..251cc68d25f5
>> +++ b/drivers/infiniband/hw/efa/efa_bitmap.c
>> @@ -0,0 +1,76 @@
>> +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
>> +/*
>> + * Copyright 2006, 2007 Cisco Systems, Inc.  All rights reserved.
>> + * Copyright 2007, 2008 Mellanox Technologies. All rights reserved.
>> + * Copyright 2018 Amazon.com, Inc. or its affiliates.
>> + */
>> +
>> +#include <linux/bitmap.h>
>> +
>> +#include "efa.h"
>> +
>> +u32 efa_bitmap_alloc(struct efa_bitmap *bitmap)
>> +{
>> +	u32 obj;
>> +
>> +	spin_lock(&bitmap->lock);
>> +
>> +	obj = find_next_zero_bit(bitmap->table, bitmap->max, bitmap->last);
>> +	if (obj >= bitmap->max)
>> +		obj = find_first_zero_bit(bitmap->table, bitmap->max);
>> +
>> +	if (obj < bitmap->max) {
>> +		set_bit(obj, bitmap->table);
>> +		bitmap->last = obj + 1;
>> +		if (bitmap->last == bitmap->max)
>> +			bitmap->last = 0;
>> +	} else {
>> +		obj = EFA_BITMAP_INVAL;
>> +	}
>> +
>> +	if (obj != EFA_BITMAP_INVAL)
>> +		--bitmap->avail;
>> +
>> +	spin_unlock(&bitmap->lock);
>> +
>> +	return obj;
>> +}
> 
> Isn't this just an ida?
> 
> Jason
> 

Will examine.
Jason Gunthorpe Dec. 7, 2018, 4:49 p.m. UTC | #3 
On Fri, Dec 07, 2018 at 10:36:12AM -0600, Tom Tucker wrote:
>    On 12/05/2018 02:56 AM, Gal Pressman wrote:
> 
> On 04-Dec-18 18:03, Jason Gunthorpe wrote:
> 
> On Tue, Dec 04, 2018 at 02:04:26PM +0200, Gal Pressman wrote:
> 
> Bitmap allocation service is currently used for assigning
> Protection Domain (PD) numbers.
> 
> Signed-off-by: Gal Pressman [1]<galpress@amazon.com>
>  drivers/infiniband/hw/efa/efa_bitmap.c | 76 ++++++++++++++++++++++++++++++++++
>  1 file changed, 76 insertions(+)
>  create mode 100644 drivers/infiniband/hw/efa/efa_bitmap.c
> 
> diff --git a/drivers/infiniband/hw/efa/efa_bitmap.c b/drivers/infiniband/hw/efa/
> efa_bitmap.c
> new file mode 100644
> index 000000000000..251cc68d25f5
> +++ b/drivers/infiniband/hw/efa/efa_bitmap.c
> @@ -0,0 +1,76 @@
> +// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
> +/*
> + * Copyright 2006, 2007 Cisco Systems, Inc.  All rights reserved.
> + * Copyright 2007, 2008 Mellanox Technologies. All rights reserved.
> + * Copyright 2018 Amazon.com, Inc. or its affiliates.
> + */
> +
> +#include <linux/bitmap.h>
> +
> +#include "efa.h"
> +
> +u32 efa_bitmap_alloc(struct efa_bitmap *bitmap)
> +{
> +       u32 obj;
> +
> +       spin_lock(&bitmap->lock);
> +
> +       obj = find_next_zero_bit(bitmap->table, bitmap->max, bitmap->last);
> +       if (obj >= bitmap->max)
> +               obj = find_first_zero_bit(bitmap->table, bitmap->max);
> +
> +       if (obj < bitmap->max) {
> +               set_bit(obj, bitmap->table);
> +               bitmap->last = obj + 1;
> +               if (bitmap->last == bitmap->max)
> +                       bitmap->last = 0;
> +       } else {
> +               obj = EFA_BITMAP_INVAL;
> +       }
> +
> +       if (obj != EFA_BITMAP_INVAL)
> +               --bitmap->avail;
> +
> +       spin_unlock(&bitmap->lock);
> +
> +       return obj;
> +}
> 
> Isn't this just an ida?
> 
> Jason
> 
> 
> Will examine.
> 
>    The idr_alloc() service uses radix trees and is not spin locked. They
>    would need to wrap the idr calls anyway and not care about the
>    performance implications.

Assiging protection domain numbers is not a performance path - and
these days ida has an internal lock that callers can use.

For the simple case of < 64*64 the performance will be very similar. A
few branches more for the IDA, but the code is also more likely to be
in cache.

Jason
diff mbox series

Patch

diff --git a/drivers/infiniband/hw/efa/efa_bitmap.c b/drivers/infiniband/hw/efa/efa_bitmap.c
new file mode 100644
index 000000000000..251cc68d25f5
--- /dev/null
+++ b/drivers/infiniband/hw/efa/efa_bitmap.c
@@ -0,0 +1,76 @@ 
+// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
+/*
+ * Copyright 2006, 2007 Cisco Systems, Inc.  All rights reserved.
+ * Copyright 2007, 2008 Mellanox Technologies. All rights reserved.
+ * Copyright 2018 Amazon.com, Inc. or its affiliates.
+ */
+
+#include <linux/bitmap.h>
+
+#include "efa.h"
+
+u32 efa_bitmap_alloc(struct efa_bitmap *bitmap)
+{
+	u32 obj;
+
+	spin_lock(&bitmap->lock);
+
+	obj = find_next_zero_bit(bitmap->table, bitmap->max, bitmap->last);
+	if (obj >= bitmap->max)
+		obj = find_first_zero_bit(bitmap->table, bitmap->max);
+
+	if (obj < bitmap->max) {
+		set_bit(obj, bitmap->table);
+		bitmap->last = obj + 1;
+		if (bitmap->last == bitmap->max)
+			bitmap->last = 0;
+	} else {
+		obj = EFA_BITMAP_INVAL;
+	}
+
+	if (obj != EFA_BITMAP_INVAL)
+		--bitmap->avail;
+
+	spin_unlock(&bitmap->lock);
+
+	return obj;
+}
+
+void efa_bitmap_free(struct efa_bitmap *bitmap, u32 obj)
+{
+	obj &= bitmap->mask;
+
+	spin_lock(&bitmap->lock);
+	bitmap_clear(bitmap->table, obj, 1);
+	bitmap->avail++;
+	spin_unlock(&bitmap->lock);
+}
+
+u32 efa_bitmap_avail(struct efa_bitmap *bitmap)
+{
+	return bitmap->avail;
+}
+
+int efa_bitmap_init(struct efa_bitmap *bitmap, u32 num)
+{
+	/* num must be a power of 2 */
+	if (!is_power_of_2(num))
+		return -EINVAL;
+
+	bitmap->last  = 0;
+	bitmap->max   = num;
+	bitmap->mask  = num - 1;
+	bitmap->avail = num;
+	spin_lock_init(&bitmap->lock);
+	bitmap->table = kcalloc(BITS_TO_LONGS(bitmap->max),
+				sizeof(long), GFP_KERNEL);
+	if (!bitmap->table)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void efa_bitmap_cleanup(struct efa_bitmap *bitmap)
+{
+	kfree(bitmap->table);
+}