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 | 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
