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From: Gal Pressman <galpress@amazon.com>
To: David Ahern <dsahern@gmail.com>
Cc: <linux-rdma@vger.kernel.org>, <netdev@vger.kernel.org>,
	Yossi Leybovich <sleybo@amazon.com>,
	Alexander Matushevsky <matua@amazon.com>,
	Leon Romanovsky <leonro@nvidia.com>,
	Jason Gunthorpe <jgg@nvidia.com>,
	Gal Pressman <galpress@amazon.com>
Subject: [PATCH iproute2-next 2/2] rdma: Add copy-on-fork to get sys command
Date: Wed, 28 Apr 2021 14:42:31 +0300	[thread overview]
Message-ID: <20210428114231.96944-3-galpress@amazon.com> (raw)
In-Reply-To: <20210428114231.96944-1-galpress@amazon.com>

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


  parent reply	other threads:[~2021-04-28 11:43 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-28 11:42 [PATCH iproute2-next 0/2] Add copy-on-fork to get sys command Gal Pressman
2021-04-28 11:42 ` [PATCH iproute2-next 1/2] rdma: update uapi headers Gal Pressman
2021-04-28 11:42 ` Gal Pressman [this message]
2021-04-28 12:00   ` [PATCH iproute2-next 2/2] rdma: Add copy-on-fork to get sys command Leon Romanovsky
2021-04-29  6:40     ` Gal Pressman

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