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@xxxxxxxxxx>
---
rdma/sys.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/rdma/sys.c b/rdma/sys.c
index 8fb565d70598..fd785b253e20 100644
--- a/rdma/sys.c
+++ b/rdma/sys.c
@@ -20,6 +20,7 @@ static const char *netns_modes_str[] = {
static int sys_show_parse_cb(const struct nlmsghdr *nlh, void *data)
{
struct nlattr *tb[RDMA_NLDEV_ATTR_MAX] = {};
+ bool cof = false;
mnl_attr_parse(nlh, 0, rd_attr_cb, tb);
@@ -35,9 +36,17 @@ static int sys_show_parse_cb(const struct nlmsghdr *nlh, void *data)
else
mode_str = "unknown";
- print_color_string(PRINT_ANY, COLOR_NONE, "netns", "netns %s\n",
+ print_color_string(PRINT_ANY, COLOR_NONE, "netns", "netns %s ",
mode_str);
}
+
+ if (tb[RDMA_NLDEV_SYS_ATTR_COPY_ON_FORK])
+ cof = 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\n",
+ cof);
+
return MNL_CB_OK;
}
--
2.31.1
