[PATCH iproute2-next 0/2] Add copy-on-fork to get sys command

[PATCH iproute2-next 0/2] Add copy-on-fork to get sys command

[Gal Pressman]

This is the userspace part for the new copy-on-fork attribute added to
the get sys netlink command.

The new attribute indicates that the kernel copies DMA pages on fork,
hence fork support through madvise and MADV_DONTFORK is not needed.

Kernel series was merged:
https://lore.kernel.org/linux-rdma/20210418121025.66849-1-galpress@amazon.com/

Thanks

Gal Pressman (2):
  rdma: update uapi headers
  rdma: Add copy-on-fork to get sys command

 rdma/include/uapi/rdma/rdma_netlink.h | 16 ++++++++++++++++
 rdma/sys.c                            |  9 +++++++++
 2 files changed, 25 insertions(+)

-- 
2.31.1

[PATCH iproute2-next 1/2] rdma: update uapi headers

[Gal Pressman]

Update rdma_netlink.h file upto kernel commit
6cc9e215eb27 ("RDMA/nldev: Add copy-on-fork attribute to get sys command")

Signed-off-by: Gal Pressman <galpress@amazon.com>
---
 rdma/include/uapi/rdma/rdma_netlink.h | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/rdma/include/uapi/rdma/rdma_netlink.h b/rdma/include/uapi/rdma/rdma_netlink.h
index 4aef76ae317b..37f583ee58fc 100644
--- a/rdma/include/uapi/rdma/rdma_netlink.h
+++ b/rdma/include/uapi/rdma/rdma_netlink.h
@@ -293,6 +293,10 @@ enum rdma_nldev_command {
 
 	RDMA_NLDEV_CMD_RES_MR_GET_RAW,
 
+	RDMA_NLDEV_CMD_RES_CTX_GET, /* can dump */
+
+	RDMA_NLDEV_CMD_RES_SRQ_GET, /* can dump */
+
 	RDMA_NLDEV_NUM_OPS
 };
 
@@ -533,6 +537,18 @@ enum rdma_nldev_attr {
 
 	RDMA_NLDEV_ATTR_RES_RAW,	/* binary */
 
+	RDMA_NLDEV_ATTR_RES_CTX,		/* nested table */
+	RDMA_NLDEV_ATTR_RES_CTX_ENTRY,		/* nested table */
+
+	RDMA_NLDEV_ATTR_RES_SRQ,		/* nested table */
+	RDMA_NLDEV_ATTR_RES_SRQ_ENTRY,		/* nested table */
+	RDMA_NLDEV_ATTR_RES_SRQN,		/* u32 */
+
+	RDMA_NLDEV_ATTR_MIN_RANGE,		/* u32 */
+	RDMA_NLDEV_ATTR_MAX_RANGE,		/* u32 */
+
+	RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK,	/* u8 */
+
 	/*
 	 * Always the end
 	 */
-- 
2.31.1

[PATCH iproute2-next 2/2] rdma: Add copy-on-fork to get sys command

[Gal Pressman]

The new attribute indicates that the kernel copies DMA pages on fork,
hence fork support through madvise and MADV_DONTFORK is not needed.

If the attribute is not reported (expected on older kernels),
copy-on-fork is disabled.

Example:
$ rdma sys
netns shared
copy-on-fork on

Signed-off-by: Gal Pressman <galpress@amazon.com>
---
 rdma/sys.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/rdma/sys.c b/rdma/sys.c
index 8fb565d70598..dd9c6da33e2a 100644
--- a/rdma/sys.c
+++ b/rdma/sys.c
@@ -38,6 +38,15 @@ static int sys_show_parse_cb(const struct nlmsghdr *nlh, void *data)
 		print_color_string(PRINT_ANY, COLOR_NONE, "netns", "netns %s\n",
 				   mode_str);
 	}
+
+	if (tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK])
+		print_color_on_off(PRINT_ANY, COLOR_NONE, "copy-on-fork",
+				   "copy-on-fork %s\n",
+				   mnl_attr_get_u8(tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK]));
+	else
+		print_color_on_off(PRINT_ANY, COLOR_NONE, "copy-on-fork",
+				   "copy-on-fork %s\n", false);
+
 	return MNL_CB_OK;
 }
 
-- 
2.31.1

Re: [PATCH iproute2-next 2/2] rdma: Add copy-on-fork to get sys command

[Leon Romanovsky]

On Wed, Apr 28, 2021 at 02:42:31PM +0300, Gal Pressman wrote:
> The new attribute indicates that the kernel copies DMA pages on fork,
> hence fork support through madvise and MADV_DONTFORK is not needed.
> 
> If the attribute is not reported (expected on older kernels),
> copy-on-fork is disabled.
> 
> Example:
> $ rdma sys
> netns shared
> copy-on-fork on

I don't think that we need to print them on separate lines.
$ rdma sys
netns shared copy-on-fork on
> 
> Signed-off-by: Gal Pressman <galpress@amazon.com>
> ---
>  rdma/sys.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/rdma/sys.c b/rdma/sys.c
> index 8fb565d70598..dd9c6da33e2a 100644
> --- a/rdma/sys.c
> +++ b/rdma/sys.c
> @@ -38,6 +38,15 @@ static int sys_show_parse_cb(const struct nlmsghdr *nlh, void *data)
>  		print_color_string(PRINT_ANY, COLOR_NONE, "netns", "netns %s\n",
>  				   mode_str);
>  	}
> +
> +	if (tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK])
> +		print_color_on_off(PRINT_ANY, COLOR_NONE, "copy-on-fork",
> +				   "copy-on-fork %s\n",
> +				   mnl_attr_get_u8(tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK]));
> +	else
> +		print_color_on_off(PRINT_ANY, COLOR_NONE, "copy-on-fork",
> +				   "copy-on-fork %s\n", false);

Let's simplify it
        bool cow = false;

 +	if (tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK])
 +		cow = mnl_attr_get_u8(tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK]);
 +
 +	print_color_on_off(PRINT_ANY, COLOR_NONE, "copy-on-fork", "copy-on-fork %s", cow);



> +
>  	return MNL_CB_OK;
>  }
>  
> -- 
> 2.31.1
> 

Re: [PATCH iproute2-next 2/2] rdma: Add copy-on-fork to get sys command

[Gal Pressman]

On 28/04/2021 15:00, Leon Romanovsky wrote:
> On Wed, Apr 28, 2021 at 02:42:31PM +0300, Gal Pressman wrote:
>> The new attribute indicates that the kernel copies DMA pages on fork,
>> hence fork support through madvise and MADV_DONTFORK is not needed.
>>
>> If the attribute is not reported (expected on older kernels),
>> copy-on-fork is disabled.
>>
>> Example:
>> $ rdma sys
>> netns shared
>> copy-on-fork on
> 
> I don't think that we need to print them on separate lines.
> $ rdma sys
> netns shared copy-on-fork on

Ack.

>> Signed-off-by: Gal Pressman <galpress@amazon.com>
>> ---
>>  rdma/sys.c | 9 +++++++++
>>  1 file changed, 9 insertions(+)
>>
>> diff --git a/rdma/sys.c b/rdma/sys.c
>> index 8fb565d70598..dd9c6da33e2a 100644
>> --- a/rdma/sys.c
>> +++ b/rdma/sys.c
>> @@ -38,6 +38,15 @@ static int sys_show_parse_cb(const struct nlmsghdr *nlh, void *data)
>>  		print_color_string(PRINT_ANY, COLOR_NONE, "netns", "netns %s\n",
>>  				   mode_str);
>>  	}
>> +
>> +	if (tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK])
>> +		print_color_on_off(PRINT_ANY, COLOR_NONE, "copy-on-fork",
>> +				   "copy-on-fork %s\n",
>> +				   mnl_attr_get_u8(tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK]));
>> +	else
>> +		print_color_on_off(PRINT_ANY, COLOR_NONE, "copy-on-fork",
>> +				   "copy-on-fork %s\n", false);
> 
> Let's simplify it
>         bool cow = false;
> 
>  +	if (tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK])
>  +		cow = mnl_attr_get_u8(tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK]);
>  +
>  +	print_color_on_off(PRINT_ANY, COLOR_NONE, "copy-on-fork", "copy-on-fork %s", cow);

Ack (changed cow -> cof).

Thanks