> On 23 Feb 2019, at 09:49, Leon Romanovsky <leon@xxxxxxxxxx> wrote:
>
> On Fri, Feb 22, 2019 at 12:51:55PM -0500, Doug Ledford wrote:
>>
>>
>>> On Feb 22, 2019, at 12:14 PM, Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx> wrote:
>>>
>>>
>>> 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.
>>
>> I don’t know, I think you make a fairly good argument for leaving it as a sysctl. We have infrastructure in place for admins to set persistent sysctl settings. The per device/link settings need something different because link names and such can change. Since these are globals, I’d leave them where they are.
>>
>
> I have patches from Parav which extend rdmatool to set global to whole
> stack parameters, something like "rdma system ...", so the option to
> set through rdmatool global parameters for modules e.g. "rdma system cma set ..."
> exists. But I'm not sure if it is right thing to do.
If decided to for the sysctl flavour, I must just say: ahem, ahem, I forgot to put in a unregister_net_sysctl_table() in cma_cleanup(). Will send a v2.
Thxs, Håkon
>
>> --
>> Doug Ledford <dledford@xxxxxxxxxx>
>> GPG KeyID: B826A3330E572FDD
>> Key fingerprint = AE6B 1BDA 122B 23B4 265B 1274 B826 A333 0E57 2FDD
