[PATCH net-next] hyperv: Add support for physically discontinuous receive buffer

[PATCH net-next] hyperv: Add support for physically discontinuous receive buffer

[Haiyang Zhang]

This will allow us to use bigger receive buffer, and prevent allocation failure
due to fragmented memory.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/channel.c            |   14 ++++++++------
 drivers/net/hyperv/hyperv_net.h |    2 +-
 drivers/net/hyperv/netvsc.c     |    7 ++-----
 3 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index cea623c..69ea36f 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -209,7 +209,6 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 {
 	int i;
 	int pagecount;
-	unsigned long long pfn;
 	struct vmbus_channel_gpadl_header *gpadl_header;
 	struct vmbus_channel_gpadl_body *gpadl_body;
 	struct vmbus_channel_msginfo *msgheader;
@@ -219,7 +218,6 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 	int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 
 	pagecount = size >> PAGE_SHIFT;
-	pfn = virt_to_phys(kbuffer) >> PAGE_SHIFT;
 
 	/* do we need a gpadl body msg */
 	pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
@@ -248,7 +246,8 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 		gpadl_header->range[0].byte_offset = 0;
 		gpadl_header->range[0].byte_count = size;
 		for (i = 0; i < pfncount; i++)
-			gpadl_header->range[0].pfn_array[i] = pfn+i;
+			gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
+				kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 		*msginfo = msgheader;
 		*messagecount = 1;
 
@@ -301,7 +300,9 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 			 * so the hypervisor gurantees that this is ok.
 			 */
 			for (i = 0; i < pfncurr; i++)
-				gpadl_body->pfn[i] = pfn + pfnsum + i;
+				gpadl_body->pfn[i] = slow_virt_to_phys(
+					kbuffer + PAGE_SIZE * (pfnsum + i)) >>
+					PAGE_SHIFT;
 
 			/* add to msg header */
 			list_add_tail(&msgbody->msglistentry,
@@ -327,7 +328,8 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 		gpadl_header->range[0].byte_offset = 0;
 		gpadl_header->range[0].byte_count = size;
 		for (i = 0; i < pagecount; i++)
-			gpadl_header->range[0].pfn_array[i] = pfn+i;
+			gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
+				kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 
 		*msginfo = msgheader;
 		*messagecount = 1;
@@ -344,7 +346,7 @@ nomem:
  * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
  *
  * @channel: a channel
- * @kbuffer: from kmalloc
+ * @kbuffer: from kmalloc or vmalloc
  * @size: page-size multiple
  * @gpadl_handle: some funky thing
  */
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index a26eecb..7b594ce 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -462,7 +462,7 @@ struct nvsp_message {
 
 #define NETVSC_MTU 65536
 
-#define NETVSC_RECEIVE_BUFFER_SIZE		(1024*1024*2)	/* 2MB */
+#define NETVSC_RECEIVE_BUFFER_SIZE		(1024*1024*16)	/* 16MB */
 
 #define NETVSC_RECEIVE_BUFFER_ID		0xcafe
 
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 93b485b..03a2c6e 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -136,8 +136,7 @@ static int netvsc_destroy_recv_buf(struct netvsc_device *net_device)
 
 	if (net_device->recv_buf) {
 		/* Free up the receive buffer */
-		free_pages((unsigned long)net_device->recv_buf,
-			get_order(net_device->recv_buf_size));
+		vfree(net_device->recv_buf);
 		net_device->recv_buf = NULL;
 	}
 
@@ -163,9 +162,7 @@ static int netvsc_init_recv_buf(struct hv_device *device)
 		return -ENODEV;
 	ndev = net_device->ndev;
 
-	net_device->recv_buf =
-		(void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
-				get_order(net_device->recv_buf_size));
+	net_device->recv_buf = vzalloc(net_device->recv_buf_size);
 	if (!net_device->recv_buf) {
 		netdev_err(ndev, "unable to allocate receive "
 			"buffer of size %d\n", net_device->recv_buf_size);
-- 
1.7.4.1

Re: [PATCH net-next] hyperv: Add support for physically discontinuous receive buffer

[David Miller]

From: Haiyang Zhang <haiyangz@microsoft.com>
Date: Thu,  9 Jan 2014 14:24:47 -0800

> This will allow us to use bigger receive buffer, and prevent allocation failure
> due to fragmented memory.
> 
> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>

Not until you start using paged SKBs in netvsc_recv_callback.

Whatever fragmention you think you're avoiding in the hyperv layer,
you're still going to get from the:

	skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);

call there.

This change makes no sense in isolation, therefore I'm not applying it
until you also include the appropriate changes to avoid the same
exact fragmentation issue in netvsc_drv.c as stated above.

RE: [PATCH net-next] hyperv: Add support for physically discontinuous receive buffer

[Haiyang Zhang]

> -----Original Message-----
> From: David Miller [mailto:davem@davemloft.net]
> Sent: Tuesday, January 14, 2014 5:32 PM
> To: Haiyang Zhang
> Cc: netdev@vger.kernel.org; KY Srinivasan; olaf@aepfle.de;
> jasowang@redhat.com; linux-kernel@vger.kernel.org; driverdev-
> devel@linuxdriverproject.org
> Subject: Re: [PATCH net-next] hyperv: Add support for physically discontinuous
> receive buffer
> 
> From: Haiyang Zhang <haiyangz@microsoft.com>
> Date: Thu,  9 Jan 2014 14:24:47 -0800
> 
> > This will allow us to use bigger receive buffer, and prevent
> > allocation failure due to fragmented memory.
> >
> > Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> > Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
> 
> Not until you start using paged SKBs in netvsc_recv_callback.
> 
> Whatever fragmention you think you're avoiding in the hyperv layer, you're still
> going to get from the:
> 
> 	skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
> 
> call there.
> 
> This change makes no sense in isolation, therefore I'm not applying it until you
> also include the appropriate changes to avoid the same exact fragmentation
> issue in netvsc_drv.c as stated above.

The receive buffer currently requires multiple MB of physically continuous memory,
and may fail to be allocated when memory is fragmented. The patch is created for
this issue.

The SKB buffer is usually less than 1500 bytes or up to several KB with jumbo frame, 
so it's much less sensitive to fragmented memory. I will work on another patch to use 
SKB buffer with discontinuous pages. 

Could you accept this patch separately?

Thanks,
- Haiyang

RE: [PATCH net-next] hyperv: Add support for physically discontinuous receive buffer

[KY Srinivasan]

> -----Original Message-----
> From: Haiyang Zhang
> Sent: Monday, January 20, 2014 2:06 PM
> To: David Miller
> Cc: netdev@vger.kernel.org; KY Srinivasan; olaf@aepfle.de;
> jasowang@redhat.com; linux-kernel@vger.kernel.org; driverdev-
> devel@linuxdriverproject.org
> Subject: RE: [PATCH net-next] hyperv: Add support for physically discontinuous
> receive buffer
> 
> 
> 
> > -----Original Message-----
> > From: David Miller [mailto:davem@davemloft.net]
> > Sent: Tuesday, January 14, 2014 5:32 PM
> > To: Haiyang Zhang
> > Cc: netdev@vger.kernel.org; KY Srinivasan; olaf@aepfle.de;
> > jasowang@redhat.com; linux-kernel@vger.kernel.org; driverdev-
> > devel@linuxdriverproject.org
> > Subject: Re: [PATCH net-next] hyperv: Add support for physically discontinuous
> > receive buffer
> >
> > From: Haiyang Zhang <haiyangz@microsoft.com>
> > Date: Thu,  9 Jan 2014 14:24:47 -0800
> >
> > > This will allow us to use bigger receive buffer, and prevent
> > > allocation failure due to fragmented memory.
> > >
> > > Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> > > Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
> >
> > Not until you start using paged SKBs in netvsc_recv_callback.
> >
> > Whatever fragmention you think you're avoiding in the hyperv layer, you're still
> > going to get from the:
> >
> > skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
> >
> > call there.
> >
> > This change makes no sense in isolation, therefore I'm not applying it until you
> > also include the appropriate changes to avoid the same exact fragmentation
> > issue in netvsc_drv.c as stated above.
> 
> The receive buffer currently requires multiple MB of physically continuous
> memory,
> and may fail to be allocated when memory is fragmented. The patch is created
> for
> this issue.
> 
> The SKB buffer is usually less than 1500 bytes or up to several KB with jumbo
> frame,
> so it's much less sensitive to fragmented memory. I will work on another patch to
> use
> SKB buffer with discontinuous pages.
> 
> Could you accept this patch separately?

Today, if we try to unload and load the network driver, the load may fail because we may 
not be able to allocate the receive buffers if memory is fragmented. This patch specifically addresses
this problem.

Regards,

K. Y
> 
> Thanks,
> - Haiyang
> 

RE: [PATCH net-next] hyperv: Add support for physically discontinuous receive buffer

[Haiyang Zhang]

> -----Original Message-----
> From: KY Srinivasan
> Sent: Monday, January 20, 2014 5:11 PM
> To: Haiyang Zhang; David Miller
> Cc: netdev@vger.kernel.org; olaf@aepfle.de; jasowang@redhat.com; linux-
> kernel@vger.kernel.org; driverdev-devel@linuxdriverproject.org
> Subject: RE: [PATCH net-next] hyperv: Add support for physically discontinuous
> receive buffer
> 
> 
> 
> > -----Original Message-----
> > From: Haiyang Zhang
> > Sent: Monday, January 20, 2014 2:06 PM
> > To: David Miller
> > Cc: netdev@vger.kernel.org; KY Srinivasan; olaf@aepfle.de;
> > jasowang@redhat.com; linux-kernel@vger.kernel.org; driverdev-
> > devel@linuxdriverproject.org
> > Subject: RE: [PATCH net-next] hyperv: Add support for physically
> > discontinuous receive buffer
> >
> >
> >
> > > -----Original Message-----
> > > From: David Miller [mailto:davem@davemloft.net]
> > > Sent: Tuesday, January 14, 2014 5:32 PM
> > > To: Haiyang Zhang
> > > Cc: netdev@vger.kernel.org; KY Srinivasan; olaf@aepfle.de;
> > > jasowang@redhat.com; linux-kernel@vger.kernel.org; driverdev-
> > > devel@linuxdriverproject.org
> > > Subject: Re: [PATCH net-next] hyperv: Add support for physically
> > > discontinuous receive buffer
> > >
> > > From: Haiyang Zhang <haiyangz@microsoft.com>
> > > Date: Thu,  9 Jan 2014 14:24:47 -0800
> > >
> > > > This will allow us to use bigger receive buffer, and prevent
> > > > allocation failure due to fragmented memory.
> > > >
> > > > Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> > > > Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
> > >
> > > Not until you start using paged SKBs in netvsc_recv_callback.
> > >
> > > Whatever fragmention you think you're avoiding in the hyperv layer,
> > > you're still going to get from the:
> > >
> > > skb = netdev_alloc_skb_ip_align(net, packet->total_data_buflen);
> > >
> > > call there.
> > >
> > > This change makes no sense in isolation, therefore I'm not applying
> > > it until you also include the appropriate changes to avoid the same
> > > exact fragmentation issue in netvsc_drv.c as stated above.
> >
> > The receive buffer currently requires multiple MB of physically
> > continuous memory, and may fail to be allocated when memory is
> > fragmented. The patch is created for this issue.
> >
> > The SKB buffer is usually less than 1500 bytes or up to several KB
> > with jumbo frame, so it's much less sensitive to fragmented memory. I
> > will work on another patch to use SKB buffer with discontinuous pages.
> >
> > Could you accept this patch separately?
> 
> Today, if we try to unload and load the network driver, the load may fail
> because we may not be able to allocate the receive buffers if memory is
> fragmented. This patch specifically addresses this problem.
> 
> Regards,
> 
> K. Y

Dave,

So, could this patch be taken first?

Thanks,
- Haiyang

Re: [PATCH net-next] hyperv: Add support for physically discontinuous receive buffer

[David Miller]

From: Haiyang Zhang <haiyangz@microsoft.com>
Date: Mon, 27 Jan 2014 21:47:43 +0000

> So, could this patch be taken first?

You always need to resend patches that I've originally rejected and
you've made arguments for.

RE: [PATCH net-next] hyperv: Add support for physically discontinuous receive buffer

[Haiyang Zhang]

> -----Original Message-----
> From: David Miller [mailto:davem@davemloft.net]
> Sent: Monday, January 27, 2014 4:51 PM
> To: Haiyang Zhang
> Cc: KY Srinivasan; netdev@vger.kernel.org; olaf@aepfle.de;
> jasowang@redhat.com; linux-kernel@vger.kernel.org; driverdev-
> devel@linuxdriverproject.org
> Subject: Re: [PATCH net-next] hyperv: Add support for physically discontinuous
> receive buffer
> 
> From: Haiyang Zhang <haiyangz@microsoft.com>
> Date: Mon, 27 Jan 2014 21:47:43 +0000
> 
> > So, could this patch be taken first?
> 
> You always need to resend patches that I've originally rejected and you've
> made arguments for.

Sure, I will re-send it now.

Thanks,
- Haiyang

[PATCH net-next] hyperv: Add support for physically discontinuous receive buffer

[Haiyang Zhang]

This will allow us to use bigger receive buffer, and prevent allocation failure
due to fragmented memory.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>
---
 drivers/hv/channel.c            |   14 ++++++++------
 drivers/net/hyperv/hyperv_net.h |    2 +-
 drivers/net/hyperv/netvsc.c     |    7 ++-----
 3 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c
index cea623c..69ea36f 100644
--- a/drivers/hv/channel.c
+++ b/drivers/hv/channel.c
@@ -209,7 +209,6 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 {
 	int i;
 	int pagecount;
-	unsigned long long pfn;
 	struct vmbus_channel_gpadl_header *gpadl_header;
 	struct vmbus_channel_gpadl_body *gpadl_body;
 	struct vmbus_channel_msginfo *msgheader;
@@ -219,7 +218,6 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 	int pfnsum, pfncount, pfnleft, pfncurr, pfnsize;
 
 	pagecount = size >> PAGE_SHIFT;
-	pfn = virt_to_phys(kbuffer) >> PAGE_SHIFT;
 
 	/* do we need a gpadl body msg */
 	pfnsize = MAX_SIZE_CHANNEL_MESSAGE -
@@ -248,7 +246,8 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 		gpadl_header->range[0].byte_offset = 0;
 		gpadl_header->range[0].byte_count = size;
 		for (i = 0; i < pfncount; i++)
-			gpadl_header->range[0].pfn_array[i] = pfn+i;
+			gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
+				kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 		*msginfo = msgheader;
 		*messagecount = 1;
 
@@ -301,7 +300,9 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 			 * so the hypervisor gurantees that this is ok.
 			 */
 			for (i = 0; i < pfncurr; i++)
-				gpadl_body->pfn[i] = pfn + pfnsum + i;
+				gpadl_body->pfn[i] = slow_virt_to_phys(
+					kbuffer + PAGE_SIZE * (pfnsum + i)) >>
+					PAGE_SHIFT;
 
 			/* add to msg header */
 			list_add_tail(&msgbody->msglistentry,
@@ -327,7 +328,8 @@ static int create_gpadl_header(void *kbuffer, u32 size,
 		gpadl_header->range[0].byte_offset = 0;
 		gpadl_header->range[0].byte_count = size;
 		for (i = 0; i < pagecount; i++)
-			gpadl_header->range[0].pfn_array[i] = pfn+i;
+			gpadl_header->range[0].pfn_array[i] = slow_virt_to_phys(
+				kbuffer + PAGE_SIZE * i) >> PAGE_SHIFT;
 
 		*msginfo = msgheader;
 		*messagecount = 1;
@@ -344,7 +346,7 @@ nomem:
  * vmbus_establish_gpadl - Estabish a GPADL for the specified buffer
  *
  * @channel: a channel
- * @kbuffer: from kmalloc
+ * @kbuffer: from kmalloc or vmalloc
  * @size: page-size multiple
  * @gpadl_handle: some funky thing
  */
diff --git a/drivers/net/hyperv/hyperv_net.h b/drivers/net/hyperv/hyperv_net.h
index a26eecb..7b594ce 100644
--- a/drivers/net/hyperv/hyperv_net.h
+++ b/drivers/net/hyperv/hyperv_net.h
@@ -462,7 +462,7 @@ struct nvsp_message {
 
 #define NETVSC_MTU 65536
 
-#define NETVSC_RECEIVE_BUFFER_SIZE		(1024*1024*2)	/* 2MB */
+#define NETVSC_RECEIVE_BUFFER_SIZE		(1024*1024*16)	/* 16MB */
 
 #define NETVSC_RECEIVE_BUFFER_ID		0xcafe
 
diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
index 93b485b..03a2c6e 100644
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -136,8 +136,7 @@ static int netvsc_destroy_recv_buf(struct netvsc_device *net_device)
 
 	if (net_device->recv_buf) {
 		/* Free up the receive buffer */
-		free_pages((unsigned long)net_device->recv_buf,
-			get_order(net_device->recv_buf_size));
+		vfree(net_device->recv_buf);
 		net_device->recv_buf = NULL;
 	}
 
@@ -163,9 +162,7 @@ static int netvsc_init_recv_buf(struct hv_device *device)
 		return -ENODEV;
 	ndev = net_device->ndev;
 
-	net_device->recv_buf =
-		(void *)__get_free_pages(GFP_KERNEL|__GFP_ZERO,
-				get_order(net_device->recv_buf_size));
+	net_device->recv_buf = vzalloc(net_device->recv_buf_size);
 	if (!net_device->recv_buf) {
 		netdev_err(ndev, "unable to allocate receive "
 			"buffer of size %d\n", net_device->recv_buf_size);
-- 
1.7.4.1

Re: [PATCH net-next] hyperv: Add support for physically discontinuous receive buffer

[David Miller]

From: Haiyang Zhang <haiyangz@microsoft.com>
Date: Mon, 27 Jan 2014 15:03:42 -0800

> This will allow us to use bigger receive buffer, and prevent allocation failure
> due to fragmented memory.
> 
> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>

Applied, thanks.