On 2/22/2019 10:36 AM, Jason Gunthorpe wrote:
> On Sun, Feb 17, 2019 at 06:09:09PM +0100, Håkon Bugge wrote:
>> During certain workloads, the default CM response timeout is too
>> short, leading to excessive retries. Hence, make it configurable
>> through sysctl. While at it, also make number of CM retries
>> configurable.
>>
>> The defaults are not changed.
>>
>> Signed-off-by: Håkon Bugge <haakon.bugge@xxxxxxxxxx>
>> drivers/infiniband/core/cma.c | 51 ++++++++++++++++++++++++++++++-----
>> 1 file changed, 44 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
>> index c43512752b8a..ce99e1cd1029 100644
>> +++ b/drivers/infiniband/core/cma.c
>> @@ -43,6 +43,7 @@
>> #include <linux/inetdevice.h>
>> #include <linux/slab.h>
>> #include <linux/module.h>
>> +#include <linux/sysctl.h>
>> #include <net/route.h>
>>
>> #include <net/net_namespace.h>
>> @@ -68,13 +69,46 @@ MODULE_AUTHOR("Sean Hefty");
>> MODULE_DESCRIPTION("Generic RDMA CM Agent");
>> MODULE_LICENSE("Dual BSD/GPL");
>>
>> -#define CMA_CM_RESPONSE_TIMEOUT 20
>> #define CMA_QUERY_CLASSPORT_INFO_TIMEOUT 3000
>> -#define CMA_MAX_CM_RETRIES 15
>> #define CMA_CM_MRA_SETTING (IB_CM_MRA_FLAG_DELAY | 24)
>> #define CMA_IBOE_PACKET_LIFETIME 18
>> #define CMA_PREFERRED_ROCE_GID_TYPE IB_GID_TYPE_ROCE_UDP_ENCAP
>>
>> +#define CMA_DFLT_CM_RESPONSE_TIMEOUT 20
>> +static int cma_cm_response_timeout = CMA_DFLT_CM_RESPONSE_TIMEOUT;
>> +static int cma_cm_response_timeout_min = 8;
>> +static int cma_cm_response_timeout_max = 31;
>> +#undef CMA_DFLT_CM_RESPONSE_TIMEOUT
>> +
>> +#define CMA_DFLT_MAX_CM_RETRIES 15
>> +static int cma_max_cm_retries = CMA_DFLT_MAX_CM_RETRIES;
>> +static int cma_max_cm_retries_min = 1;
>> +static int cma_max_cm_retries_max = 100;
>> +#undef CMA_DFLT_MAX_CM_RETRIES
>> +
>> +static struct ctl_table_header *cma_ctl_table_hdr;
>> +static struct ctl_table cma_ctl_table[] = {
>> + {
>> + .procname = "cma_cm_response_timeout",
>> + .data = &cma_cm_response_timeout,
>> + .maxlen = sizeof(cma_cm_response_timeout),
>> + .mode = 0644,
>> + .proc_handler = proc_dointvec_minmax,
>> + .extra1 = &cma_cm_response_timeout_min,
>> + .extra2 = &cma_cm_response_timeout_max,
>> + },
>> + {
>> + .procname = "cma_max_cm_retries",
>> + .data = &cma_max_cm_retries,
>> + .maxlen = sizeof(cma_max_cm_retries),
>> + .mode = 0644,
>> + .proc_handler = proc_dointvec_minmax,
>> + .extra1 = &cma_max_cm_retries_min,
>> + .extra2 = &cma_max_cm_retries_max,
>> + },
>> + { }
>> +};
> Is sysctl the right approach here? Should it be rdma tool instead?
>
> Jason
There are other rdma sysctls currently: net.rdma_ucm.max_backlog and
net.iw_cm.default_backlog. The core network stack seems to use sysctl
and not ip tool to set basically globals.
To use rdma tool, we'd have to have some concept of a "module" object, I
guess. IE there's dev, link, and resource rdma tool objects currently.
But these cma timeout settings are really not per dev, link, nor a
resource. Maybe we have just a "core" object: rdma core set
cma_max_cm_retries min 8 max 30.
